Field Identifiable Subspecies of birds – an annotated list

Below is a draft list of Field Identifiable subspecies of North American birds. Some discussion of the concept behind the list is here. Any suggestions are welcome in the comments section below. Work on the list is ongoing, and if you want to read even more “behind-the-scenes” stuff there is a discussion at Birdforum here.

* Red asterisk indicates species that qualify for my subjective and arbitrary judgement as the forms most likely to be split. I have added this mainly as a way to highlight the most distinctive subspecies. Feel free to suggest changes.

Family Anatidae – Swans, Geese and Ducks

Black-bellied Whistling-DuckDendrocygna autumnalis

Fulvous Whistling-DuckDendrocygna bicolor

Taiga Bean-GooseAnser fabalis

Tundra Bean-GooseAnser serrirostris

Pink-footed GooseAnser brachyrhynchus

Greater White-fronted GooseAnser albifrons

Greenland form is fairly distinctive and usually reliably identified in the field, other forms less distinctive, intergrading, and not reliably identified out of range. ––Read more…

Greater White-fronted Goose (Greenland) – Anser albifrons flavirostris

Greater White-fronted Goose (American) – Anser albifrons gambeli group

Lesser White-fronted GooseAnser erythropus

Greylag GooseAnser anser

Emperor GooseChen canagica

Snow GooseChen caerulescens

Two subspecies are distinguished by overall size, but there is considerable overlap and identifying an individual out of range usually cannot be done with a high degree of confidence.

Snow Goose (Lesser) – Chen caerulescens caerulescens

Snow Goose (Greater) – Chen caerulescens atlantica

Ross’s GooseChen rossii

BrantBranta bernicla

Three named subspecies recorded in North America, including five distinct populations. Several can be identified in the field with a high level of confidence. Intergrades are rare but greatly complicate identification.

Brant (Dark-bellied or Eurasian) – Branta bernicla bernicla

Brant (Pale-bellied or Atlantic) – Branta bernicla hrota

Brant (Black or Pacific) – Branta bernicla nigricans

Brant (Western High Arctic or Gray-bellied) – Branta bernicla ? subspecies unassigned

Barnacle GooseBranta leucopsis

Cackling GooseBranta hutchinsii

Four subspecies fall into two groups, “Pacific” minima and Aleutian subspecies can be distinguished from each other and together form a group breeding in western Alaska. Subspecies hutchinsii and taverneri nest in northern Alaska and arctic Canada; cannot be distinguished from each other but together are distinguishable from Pacific forms. ––Read more…

Cackling Goose (Pacific) – Branta hutchinsii minima *

Cackling Goose (Aleutian) – Branta hutchinsii leucopareia

Cackling Goose (Richardson’s) – Branta hutchinsii hutchinsii group *

Canada GooseBranta canadensis

Seven subspecies, but there is so much variation and overlap that, while it is possible to pick out individuals and flocks that show the characteristics of one subspecies, these may not be safely identifiable out of range. The groups listed here can be identified with some confidence under the right circumstances. ––Read more…

Canada Goose (Dusky) – Branta canadensis occidentalis group

Canada Goose (Typical) – Branta canadensis canadensis group

Canada Goose (Lesser) – Branta canadensis parvipes

Mute SwanCygnus olor

Trumpeter SwanCygnus buccinator

Tundra SwanCygnus columbianus

Two subspecies distinguished by extent of yellow on bill. Virtually all individuals can be identified, with little overlap, and several authorities currently split these into two species, but no known differences in voice, behavior, or structure.

Tundra Swan (Whistling) – Cygnus columbianus columbianus

Tundra Swan (Bewick’s) – Cygnus columbianus bewickii

Whooper SwanCygnus cygnus

Muscovy DuckCairina moschata

Wood DuckAix sponsa

GadwallAnas strepera

Falcated DuckAnas falcata

Eurasian WigeonAnas penelope

American WigeonAnas americana

American Black DuckAnas rubripes

MallardAnas platyrhynchos

Mexican Mallard is nearly 100% identifable and is split by several authorities, extent of intergradation with Northern Mallard is debated.

Mallard (Northern) – Anas platyrhynchos platyrhynchos group *

Mallard (Mexican) – Anas platyrhynchos diazi *

Mottled DuckAnas fulvigula

Florida and Gulf Coast populations differ significantly in DNA, slightly and on average in plumage. It is doubtful that they could be confidently identified in the field, but more study is warranted.

Eastern Spot-billed DuckAnas zonorhyncha

Blue-winged TealAnas discors

Cinnamon TealAnas cyanoptera

Northern ShovelerAnas clypeata

White-cheeked PintailAnas bahamensis

Northern PintailAnas acuta

GarganeyAnas querquedula

Baikal TealAnas formosa

Green-winged TealAnas crecca

Two subspecies easily distinguished in adult male plumage and differ significantly in DNA, split by many authorities, but no consistent differences in other plumages, voice, structure, or behavior,

Green-winged Teal (Common or Eurasian) – Anas crecca crecca group

Green-winged Teal (American) – Anas crecca carolinensis

CanvasbackAythya valisineria

RedheadAythya americana

Common PochardAythya ferina

Ring-necked DuckAythya collaris

Tufted DuckAythya fuligula

Greater ScaupAythya marila

Lesser ScaupAythya affinis

Steller’s EiderPolysticta stelleri

Spectacled EiderSomateria fischeri

King EiderSomateria spectabilis

Common EiderSomateria mollissima

Four subspecies in North America and two additional in Europe. The West Arctic form is the most distinctive, differing in plumage, size, and bill structure, and seems a good candidate for splitting. The three eastern North American forms are more similar to each other, with overlap in many features and intergrades where ranges meet, but many or most are still identifiable.

Common Eider (Pacific) – Somateria mollissima v-nigra *

Common Eider (Maritime Canada) – Somateria mollissima dresseri

Common Eider (East Arctic) – Somateria mollissima borealis

Common Eider (Hudson Bay) – Somateria mollissima sedentaria

Harlequin DuckHistrionicus histrionicus

Labrador DuckCamptorhynchus labradorius

Surf ScoterMelanitta perspicillata

White-winged ScoterMelanitta fusca

Adult males of Siberian subspecies (recorded a few times in western Alaska) are safely distinguishable from American subspecies.

White-winged Scoter (Stejneger’s or Siberian) – Melanitta fusca stejnegeri

White-winged Scoter (American) – Melanitta fusca deglandi

Black ScoterMelanitta americana

Long-tailed DuckClangula hyemalis

BuffleheadBucephala albeola

Common GoldeneyeBucephala clangula

Eurasian subspecies recorded at least once in Alaska differs slightly in size and proportions, and might just be identifiable. More study is needed.

Barrow’s GoldeneyeBucephala islandica

SmewMergellus albellus

Hooded MerganserLophodytes cucullatus

Common MerganserMergus merganser

Eurasian subspecies known as Goosander (rare but regular in western Alaska) is safely distinguishable from American subspecies by wing pattern and probably by bill and head shape.

Common Merganser (Goosander or Eurasian) – Mergus merganser merganser group *

Common Merganser (American) – Mergus merganser americanus *

Red-breasted MerganserMergus serrator

Masked DuckNomonyx dominicus

Ruddy DuckOxyura jamaicensis

Family Cracidae – Chachalacas and Guans

Plain ChachalacaOrtalis vetula

Family Odontophoridae – New World Quail

Mountain QuailOreortyx pictus

Scaled QuailCallipepla squamata

Birds in southern Texas are browner overall, and males have a chestnut belly patch lacking in others, which probaby allows reliable identification, but more study is needed to assess variation.

California QuailCallipepla californica

Gambel’s QuailCallipepla gambelii

Northern BobwhiteColinus virginianus

Variation in Northern Bobwhite across eastern North America is subtle and clinal, and natural variations are now swamped by many released birds. Masked Bobwhite of southwest is very distinctive, males 100% identifiable by plumage (but only by plumage), females are virtually identical to Eastern birds.

Northern Bobwhite (Eastern) – Colinus virginianus virginianus group *

Northern Bobwhite (Masked) – Colinus virginianus ridgwayi *

Montezuma QuailCyrtonyx montezumae

Family Phasianidae – Grouse and Pheasants

ChukarAlectoris chukar

Himalayan SnowcockTetraogallus himalayensis

Gray PartridgePerdix perdix

Ring-necked PheasantPhasianus colchicus

Across its wide native range this species occurs in five identifiable forms. Most distinctive is the Green Pheasant of Japan, split by many authorities and introduced locally in the US. Populations in North America are derived from at least three of the other four forms, but extensive mixing of captive bred stock makes subspecies ID here essentially impossible.

Ruffed GrouseBonasa umbellus

Greater Sage-GrouseCentrocercus urophasianus

Gunnison Sage-GrouseCentrocercus minimus

Spruce GrouseFalcipennis canadensis

Two subspecies groups differ in male plumage and display and are good candidates for species status. Females are probably indistinguishable.

Spruce Grouse (Taiga) – Falcipennis canadensis canadensis group *

Spruce Grouse (Franklin’s or Pacific) – Falcipennis canadensis franklinii group *

Willow PtarmiganLagopus lagopus

Recent DNA studies indicate several distinct populations in North America. More study needed to determine whether any are identifiable in the field.

Rock PtarmiganLagopus muta

Several distinctive populations in the Aleutian Islands and elsewhere differ in plumage and possibly display, more study is needed.

White-tailed PtarmiganLagopus leucura

Dusky GrouseDendragapus obscurus

Sooty GrouseDendragapus fuliginosus

Sharp-tailed GrouseTympanuchus phasianellus

Greater Prairie-ChickenTympanuchus cupido

Texas (Atwater’s) subspecies differs slightly but reliably in size and plumage. The Heath Hen T. c. cupido was relatively distinctive but now extinct.

Greater Prairie-Chicken (Northern) – Tympanuchus cupido pinnatus

Greater Prairie-Chicken (Texas or Attwater’s) – Tympanuchus cupido attwateri

Lesser Prairie-ChickenTympanuchus pallidicinctus

Wild TurkeyMeleagris gallopavo

Southwestern birds differ in plumage, but similar birds can be found in the east and it is unclear whether these are variations of the local population or introgression through releases of captive-bred birds. Reintroduction efforts have clouded the natural patterns of variation, rendering the subspecies names less meaningful.

Wild Turkey (Eastern ) – Meleagris gallopavo silvestris

Wild Turkey (Merriam’s or Southwestern) – Meleagris gallopavo merriami

Family Gaviidae – Loons

Red-throated LoonGavia stellata

Arctic LoonGavia arctica

Pacific LoonGavia pacifica

Common LoonGavia immer

Yellow-billed LoonGavia adamsii

Family Podicipedidae – Grebes

Least GrebeTachybaptus dominicus

Pied-billed GrebePodilymbus podiceps

Horned GrebePodiceps auritus

Red-necked GrebePodiceps grisegena

Eared GrebePodiceps nigricollis

Western GrebeAechmophorus occidentalis

Clark’s GrebeAechmophorus clarkii

Family Phoenicopteridae – Flamingos

American FlamingoPhoenicopterus ruber

Family Diomedeidae – Albatrosses

Yellow-nosed AlbatrossThalassarche chlororhynchos

All identifiable North American records are of the expected Atlantic subspecies T. c. chlororhynchos. The Indian Ocean form T. c. carteri is split by many authorities.

Shy AlbatrossThalassarche cauta

The few North American occurrences include confirmed records of cauta and well-documented records of birds showing the features of salvini. These are considered separate species by most authorities.

Shy Albatross (White-capped) – Thalassarche cauta cauta *

Shy Albatross (Salvin’s) – Thalassarche cauta salvini *

Black-browed AlbatrossThalassarche melanophris

North American records to date involve the expected T. m. melanophris. The New Zealand breeding subspecies T. m. impavida is split by some authorities.

Light-mantled AlbatrossPhoebetria palpebrata

Wandering AlbatrossDiomedea exulans

This species is now split by many authorities into four separate species. Of two North American records, one in Oregon was identified as the New Zealand breeding D. e. antipodensis and one from California could have been that subspecies or the nominate. Any future record will have to be carefully studied to determine its subspecies/species.

Laysan AlbatrossPhoebastria immutabilis

Black-footed AlbatrossPhoebastria nigripes

Short-tailed AlbatrossPhoebastria albatrus

Family Procellariidae – Shearwaters and Petrels

Northern FulmarFulmarus glacialis

Two subspecies groups are reliably distinguished by plumage and also differ in DNA and slightly in bill size and proportions.

Northern Fulmar (Atlantic) – Fulmarus glacialis glacialis group *

Northern Fulmar (Pacific) – Fulmarus glacialis rodgersii *

Great-winged PetrelPterodroma macroptera

North American records refer to P. m. gouldi

Herald PetrelPterodroma arminjoniana

Many authorities split the Atlantic form, which accounts for all North American records, as Trindade Petrel P. arminjoniana.

Murphy’s PetrelPterodroma ultima

Fea’s PetrelPterodroma feae

Now split from Zino’s Petrel (P. madeira), and some authorities further split Desertas Petrel (P. deserta), both of which are potential visitors to North America.

Mottled PetrelPterodroma inexpectata

Bermuda PetrelPterodroma cahow

Black-capped PetrelPterodroma hasitata

Observers off North Carolina have identified two or three distinct types there based on plumage and bill size, which might represent separate populations, but further study is needed to clarify the situation.

Hawaiian or Galapagos Petrel – Pterodroma sandwichensis or phaeopygia

Formerly Dark-rumped Petrel but now split into two species. It has been argued that records to date in North America involve Hawaiian Petrel, but this is not confirmed and both could occur.

Cook’s PetrelPterodroma cookii

Stejneger’s PetrelPterodroma longirostris

Bulwer’s PetrelBulweria bulwerii

White-chinned PetrelProcellaria aequinoctialis

Parkinson’s PetrelProcellaria parkinsoni

Streaked ShearwaterCalonectris leucomelas

Cory’s ShearwaterCalonectris diomedea

Two subspecies groups differ on average in size, plumage, and voice, but there is some overlap and the possibility of distinguishing them reliably in the field remains to be confirmed.

Cory’s Shearwater (Mediterranean or Scopoli’s) – Calonectris diomedea diomedea

Cory’s Shearwater (Atlantic) – Calonectris diomedea borealis

Cape Verde ShearwaterCalonectris edwardsii

Pink-footed ShearwaterPuffinus creatopus

Flesh-footed ShearwaterPuffinus carneipes

Great ShearwaterPuffinus gravis

Wedge-tailed ShearwaterPuffinus pacificus

Buller’s ShearwaterPuffinus bulleri

Sooty ShearwaterPuffinus griseus

Short-tailed ShearwaterPuffinus tenuirostris

Manx ShearwaterPuffinus puffinus

Townsend’s ShearwaterPuffinus auricularis

Black-vented ShearwaterPuffinus opisthomelas

Little ShearwaterPuffinus assimilis

Confirmed North American records in MA and NS refer to the Azores breeding form Barolo Shearwater P. a baroli which most authorities split from Little Shearwater. One report off California, if accepted, almost certainly refers to a different subspecies (species) and other forms could occur.

Audubon’s ShearwaterPuffinus lherminieri

Family Hydrobatidae – Storm-Petrels

Wilson’s Storm-PetrelOceanites oceanicus

White-faced Storm-PetrelPelagodroma marina

European Storm-PetrelHydrobates pelagicus

Two separate breeding populations (Atlantic and Mediterranean) differ in size and voice and have been split by some authorities, but they may not be distinguishable in the field. The few North American records presumably represent the Atlantic-breeding population, but confirmation is needed.

Black-bellied Storm-PetrelFregetta tropica

Fork-tailed Storm-PetrelOceanodroma furcata

Northern and Southern breeding populations differ in overall plumage color and average size and might just be identifiable in the field.

Ringed Storm-PetrelOceanodroma hornbyi

Leach’s Storm-PetrelOceanodroma leucorhoa

Four subspecies present a confusing mosaic of variation, with differences in size, structure, plumage color, habits, voice, and time of breeding. Relatively large and white-rumped birds are widespread in the Atlantic and North Pacific, while smaller white- and dark-rumped populations occur off Southern California. Probably best considered three populations, but how best to divide this variation into identifiable forms, and how reliably they can be identified in the field, remains to be determined. ––Read more…

Swinhoe’s Storm-PetrelOceanodroma monorhis

Ashy Storm-PetrelOceanodroma homochroa

Band-rumped Storm-PetrelOceanodroma castro

North Atlantic populations of this species may be split into three or four species, which will be extremely difficult to distinguish at sea. More study is needed.

Wedge-rumped Storm-PetrelOceanodroma tethys

Black Storm-PetrelOceanodroma melania

Tristram’s Storm-PetrelOceanodroma tristrami

Least Storm-PetrelOceanodroma microsoma

Family Phaethontidae – Tropicbirds

White-tailed TropicbirdPhaethon lepturus

Red-billed TropicbirdPhaethon aethereus

Red-tailed TropicbirdPhaethon rubricauda

Family Ciconiidae – Storks

JabiruJabiru mycteria

Wood StorkMycteria americana

Family Fregatidae – Frigatebirds

Magnificent FrigatebirdFregata magnificens

Great FrigatebirdFregata minor

Lesser FrigatebirdFregata ariel

Family Sulidae – Boobies

Masked BoobySula dactylatra

Blue-footed BoobySula nebouxii

Brown BoobySula leucogaster

Adult males are reliably distinguished by head color. No other differences are known, so while a pale-headed bird in the Atlantic could probably be reliably identified as a vagrant from the Pacific, no other age/sex class can be identified.

Brown Booby (Eastern Pacific or Brewster’s) – Sula leucogaster brewsteri

Brown Booby (Atlantic) – Sula leucogaster leucogaster

Red-footed BoobySula sula

Some differences between Atlantic and Pacific forms may allow identification, but more study is needed.

Northern GannetMorus bassanus

Family Phalacrocoracidae – Cormorants

Brandt’s CormorantPhalacrocorax penicillatus

Neotropic CormorantPhalacrocorax brasilianus

Double-crested CormorantPhalacrocorax auritus

Some western birds have obvious white crests in breeding plumage and may be identifiable, but many have black crests like eastern birds.

Great CormorantPhalacrocorax carbo

Red-faced CormorantPhalacrocorax urile

Pelagic CormorantPhalacrocorax pelagicus

Family Anhingidae – Anhingas

AnhingaAnhinga anhinga

Family Pelecanidae – Pelicans

American White PelicanPelecanus erythrorhynchos

Brown PelicanPelecanus occidentalis

Two populations usually differ in pouch color, but both colors are found in both populations, just in different frequencies. In practical terms this means that a vagrant cannot be identified. ––Read more…

Family Ardeidae – Herons and Egrets

American BitternBotaurus lentiginosus

Yellow BitternIxobrychus sinensis

Least BitternIxobrychus exilis

Bare-throated Tiger-HeronTigrisoma mexicanum

Great Blue HeronArdea herodias

The restricted population in the Florida Keys differs from the widespread birds in average size, average plume length, and color (all-white). These have been split as Great White Heron in the past, but whether this population is best considered a species, subspecies, or merely a morph is still a subject of debate. ––Read more…

Great Blue Heron (Typical) – Ardea herodias herodias group

Great Blue Heron (Great White) – Ardea herodias occidentalis

Grey HeronArdea cinerea

Great EgretArdea alba

Records in Virginia and western Alaska have been suspected of being the African and Asian subspecies, respectively, which may be elevated to species status, but identification has not been confirmed and ID criteria need to be worked out.

Intermediate EgretMesophoyx intermedia

Chinese EgretEgretta eulophotes

Little EgretEgretta garzetta

Western Reef-HeronEgretta gularis

Snowy EgretEgretta thula

Little Blue HeronEgretta caerulea

Tricolored HeronEgretta tricolor

Reddish EgretEgretta rufescens

Cattle EgretBubulcus ibis

The Western subspecies is widespread in North America; Eastern (Asian) has been recorded at least once in western Alaska. It differs in size and breeding plumage, and is split by several authorities.

Cattle Egret (Western or African) – Bubulcus ibis ibis group

Cattle Egret (Eastern or Asian) – Bubulcus ibis coromandus

Chinese Pond-HeronArdeola bacchus

Green HeronButorides virescens

Black-crowned Night-HeronNycticorax nycticorax

Eurasian form presumably accounts for records in Aleutian Islands, but unconfirmed. Differences are slight.

Black-crowned Night-Heron (Eurasian) – Nycticorax nycticorax nycticorax

Black-crowned Night-Heron (American) – Nycticorax nycticorax hoactli

Yellow-crowned Night-HeronNyctanassa violacea

Family Threskiornithidae – Ibises and Spoonbills

White IbisEudocimus albus

Scarlet IbisEudocimus ruber

Glossy IbisPlegadis falcinellus

White-faced IbisPlegadis chihi

Roseate SpoonbillPlatalea ajaja

Family Cathartidae – New World Vultures

Black VultureCoragyps atratus

Turkey VultureCathartes aura

California CondorGymnogyps californianus

Family Pandionidae – Osprey

OspreyPandion haliaetus

Breeders of Florida and the West Indies differ in head pattern, but probably not reliably identified out of range. Eurasian populations (unrecorded in North America) are split by many authorities.

Family Accipitridae – Hawks and Eagles

Hook-billed KiteChondrohierax uncinatus

Swallow-tailed KiteElanoides forficatus

White-tailed KiteElanus leucurus

Snail KiteRostrhamus sociabilis

Mississippi KiteIctinia mississippiensis

Bald EagleHaliaeetus leucocephalus

White-tailed EagleHaliaeetus albicilla

Steller’s Sea-EagleHaliaeetus pelagicus

Northern HarrierCircus cyaneus

Most authorities split the Eurasian populations as Hen Harrier C. cyaneus (unrecorded in North America) from American C, hudsonius

Sharp-shinned HawkAccipiter striatus

Cooper’s HawkAccipiter cooperii

Northern GoshawkAccipiter gentilis

Crane HawkGeranospiza caerulescens

Common Black-HawkButeogallus anthracinus

Harris’s HawkParabuteo unicinctus

Roadside HawkButeo magnirostris

Red-shouldered HawkButeo lineatus

Eastern and Florida populations differ from each other only in plumage color saturation. California birds are more distinctive (especially juvenile plumage) and should be identifiable in virtually all cases.

Red-shouldered Hawk (Eastern) – Buteo lineatus lineatus group

Red-shouldered Hawk (Florida) – Buteo lineatus extimus

Red-shouldered Hawk (California) – Buteo lineatus elegans

Broad-winged HawkButeo platypterus

Gray HawkButeo nitidus

Short-tailed HawkButeo brachyurus

Swainson’s HawkButeo swainsoni

White-tailed HawkButeo albicaudatus

Zone-tailed HawkButeo albonotatus

Red-tailed HawkButeo jamaicensis

Most subspecies differ only slightly and on average in plumage, and are barely distinguishable except by subjective judgment and considering location. Krider’s may be only a morph. Harlan’s Hawk (B. j. harlani) is the exception, and is nearly 100% identifiable.

Red-tailed Hawk (Western) – Buteo jamaicensis calurus group

Red-tailed Hawk (Eastern) – Buteo jamaicensis borealis group

Red-tailed Hawk (Harlan’s) – Buteo jamaicensis harlani

Red-tailed Hawk (Krider’s) – Buteo jamaicensis kriderii

Red-tailed Hawk (Southwestern) – Buteo jamaicensis fuertesi

Ferruginous HawkButeo regalis

Rough-legged HawkButeo lagopus

Golden EagleAquila chrysaetos

Family Falconidae – Falcons

Collared Forest-FalconMicrastur semitorquatus

Crested CaracaraCaracara cheriway

Eurasian KestrelFalco tinnunculus

American KestrelFalco sparverius

Red-footed FalconFalco vespertinus

MerlinFalco columbarius

Three subspecies are usually identifiable by differences in overall color, although intergrades do occur and no differences in structure or voice are known. In addition, Siberian birds differ significantly in DNA, slightly in plumage. These have been reported in western Alaska but not confirmed.

Merlin (American Taiga) – Falco columbarius columbarius

Merlin (Prairie or Richardson’s) – Falco columbarius richardsonii

Merlin (Pacific or Black) – Falco columbarius suckleyi

Eurasian HobbyFalco subbuteo

Aplomado FalconFalco femoralis

GyrfalconFalco rusticolus

Peregrine FalconFalco peregrinus

Three subspecies differ slightly in details of plumage color and pattern. Most are probably identifiable with reasonable confidence, although the reintroduced populations in eastern US comprise a fourth group and can be confusingly similar to Continental and Peale’s.

Prairie FalconFalco mexicanus

Family Rallidae – Rails, Gallinules, and Coots

Yellow RailCoturnicops noveboracensis

Black RailLaterallus jamaicensis

Corn CrakeCrex crex

Clapper RailRallus longirostris

Atlantic and Gulf Coast forms differ from each other only in overall plumage tones and average size, and are connected by intermediate populations. California population is separate and distinctive, differing in plumage, shape, and DNA.

Clapper Rail (Eastern) – Rallus longirostris crepitans group

Clapper Rail (California) – Rallus longirostris obsoletus group

King RailRallus elegans

Virginia RailRallus limicola

SoraPorzana carolina

Paint-billed CrakeNeocrex erythrops

Spotted RailPardirallus maculatus

Purple SwamphenPorphyrio porphyrio

Purple GallinulePorphyrio martinica

Common MoorhenGallinula chloropus

Eurasian CootFulica atra

American CootFulica americana

White-shielded birds are merely a morph of American Coot and not Caribean Coot. ––Read more…

Family Heliornithidae – Sungrebes

SungrebeHeliornis fulica

Family Aramidae – Limpkin

LimpkinAramus guarauna

Family Gruidae – Cranes

Sandhill CraneGrus canadensis

Extremes of size are distinctive and reliably identifiable, but G. c. rowani is intermediate in size. In California, for example, rowani does not occur so two distinct size classes are present. In most of North America rowani is common and a complete range of size is apparent.

Sandhill Crane (Lesser or Northern) – Grus canadensis canadensis

Sandhill Crane (Greater or Southern) – Grus canadensis pratensis group

Common CraneGrus grus

Whooping CraneGrus americana

Family Burhinidae – Thick-knees

Double-striped Thick-kneeBurhinus bistriatus

Family Charadriidae – Plovers and Lapwings

Northern LapwingVanellus vanellus

Black-bellied PloverPluvialis squatarola

European Golden-PloverPluvialis apricaria

American Golden-PloverPluvialis dominica

Pacific Golden-PloverPluvialis fulva

Lesser Sand-PloverCharadrius mongolus

Some authorities split the Northern mongolusatrifrons group. All North American records to date are the subspecies C. m. stegmanni of the mongolus group.

Greater Sand-PloverCharadrius leschenaultii

Collared PloverCharadrius collaris

Snowy PloverCharadrius alexandrinus

Old World forms differ significantly in DNA and voice, slightly in plumage and are often split as Kentish Plover C. alexandrinus, but have not been recorded in North America. North American birds then become C. nivosus.

Wilson’s PloverCharadrius wilsonia

Common Ringed PloverCharadrius hiaticula

Semipalmated PloverCharadrius semipalmatus

Piping PloverCharadrius melodus

Little Ringed PloverCharadrius dubius

KilldeerCharadrius vociferus

Mountain PloverCharadrius montanus

Eurasian DotterelCharadrius morinellus

Family Haematopodidae – Oystercatchers

Eurasian OystercatcherHaematopus ostralegus

American OystercatcherHaematopus palliatus

Two subspecies reliably distinguished by wing and tail pattern and completely separated by range.

American Oystercatcher (Atlantic) – Haematopus palliatus palliatus

American Oystercatcher (Pacific) – Haematopus palliatus frazari

Black OystercatcherHaematopus bachmani

Family Recurvirostridae – Avocets and Stilts

Black-winged StiltHimantopus himantopus

Black-necked StiltHimantopus mexicanus

One record (in Tennessee) of a bird showing characteristic of the South American subspecies H. m. melanurus but whether this was an actual vagrant from South America or a variant of the local population is unknown.

American AvocetRecurvirostra americana

Family Jacanidae – Jacanas

Northern JacanaJacana spinosa

Family Scolopacidae – Sandpipers

Terek SandpiperXenus cinereus

Common SandpiperActitis hypoleucos

Spotted SandpiperActitis macularius

Green SandpiperTringa ochropus

Solitary SandpiperTringa solitaria

Two subspecies (Eastern and Western) differ substantially in DNA, but apparently very little in plumage and no differences are known in voice or behavior. Criteria for identification in the field remain to be discovered.

Solitary Sandpiper (Eastern) – Tringa solitaria solitaria

Solitary Sandpiper (Western) – Tringa solitaria cinnamomea

Gray-tailed TattlerTringa brevipes

Wandering TattlerTringa incana

Spotted RedshankTringa erythropus

Greater YellowlegsTringa melanoleuca

Common GreenshankTringa nebularia

WilletTringa semipalmata

Two subspecies differ fundamentally in appearance, voice, and migratory routes.

Willet (Eastern) – Tringa semipalmata semipalmata *

Willet (Western) – Tringa semipalmata inornata *

Lesser YellowlegsTringa flavipes

Marsh SandpiperTringa stagnatilis

Wood SandpiperTringa glareola

Common RedshankTringa totanus

Upland SandpiperBartramia longicauda

Little CurlewNumenius minutus

WhimbrelNumenius phaeopus

Three subspecies all readily identifiable by plumage, but no reliable differences known in structure or voice. European and Asian forms are rare visitors to North America, and DNA studies reveal a substantial difference between American and Asian subspecies.

Whimbrel (European) – Numenius phaeopus phaeopus *

Whimbrel (Asian) – Numenius phaeopus variegatus *

Whimbrel (American) – Numenius phaeopus hudsonicus *

Bristle-thighed CurlewNumenius tahitiensis

Far Eastern CurlewNumenius madagascariensis

Slender-billed CurlewNumenius tenuirostris

Eurasian CurlewNumenius arquata

Long-billed CurlewNumenius americanus

Black-tailed GodwitLimosa limosa

Three subspecies, all rare visitors to North America. Icelandic and European are barely distinguishable, but Asian differs in size and DNA and is split by some authorities, although field ID criteria still need to be worked out.

Black-tailed Godwit (European) – Limosa limosa limosa

Black-tailed Godwit (Icelandic) – Limosa limosa islandica

Black-tailed Godwit (Asian) – Limosa limosa melanuroides

Hudsonian GodwitLimosa haemastica

Bar-tailed GodwitLimosa lapponica

European and Asian forms are readily distinguished in the field by plumage.

Bar-tailed Godwit (European or Western) – Limosa lapponica lapponica

Bar-tailed Godwit (Asian or Eastern) – Limosa lapponica baueri

Marbled GodwitLimosa fedoa

Ruddy TurnstoneArenaria interpres

Black TurnstoneArenaria melanocephala

SurfbirdAphriza virgata

Great KnotCalidris tenuirostris

Red KnotCalidris canutus

SanderlingCalidris alba

Semipalmated SandpiperCalidris pusilla

Western SandpiperCalidris mauri

Red-necked StintCalidris ruficollis

Little StintCalidris minuta

Temminck’s StintCalidris temminckii

Long-toed StintCalidris subminuta

Least SandpiperCalidris minutilla

White-rumped SandpiperCalidris fuscicollis

Baird’s SandpiperCalidris bairdii

Pectoral SandpiperCalidris melanotos

Sharp-tailed SandpiperCalidris acuminata

Purple SandpiperCalidris maritima

Rock SandpiperCalidris ptilocnemis

Pribilof population is distinctive in size and plumage. Aleutian and Mainland subspecies are similar to each other and are lumped here, but it may be possible to distinguish them as well.

Rock Sandpiper (Pribilof) – Calidris ptilocnemis ptilocnemis

Rock Sandpiper (Aleutian/Mainland) – Calidris ptilocnemis couesi group

DunlinCalidris alpina

Greenland Dunlin a very rare visitor to eastern North America and readily identifiable. Recent research shows that American Dunlin comprise more than one population – Dunlin in western North America are disjunct from eastern birds and distinct genetically, but field ID, if possible, still needs to be sorted out.

Dunlin (American) – Calidris alpina pacifica group *

Dunlin (Greenland) – Calidris alpina arctica group *

Curlew SandpiperCalidris ferruginea

Stilt SandpiperCalidris himantopus

Spoon-billed SandpiperEurynorhynchus pygmeus

Broad-billed SandpiperLimicola falcinellus

Buff-breasted SandpiperTryngites subruficollis

RuffPhilomachus pugnax

Short-billed DowitcherLimnodromus griseus

Three subspecies more or less identifiable in breeding plumage, but not at other times. No differences in structure or voice.

Short-billed Dowitcher (Atlantic) – Limnodromus griseus griseus

Short-billed Dowitcher (Central or Henderson’s) – Limnodromus griseus hendersoni

Pacific Short-billed Dowitcher – Limnodromus griseus caurinus

Long-billed DowitcherLimnodromus scolopaceus

Jack SnipeLymnocryptes minimus

Solitary SnipeGallinago solitaria

Wilson’s SnipeGallinago delicata

Common SnipeGallinago gallinago

Pin-tailed SnipeGallinago stenura

Eurasian WoodcockScolopax rusticola

American WoodcockScolopax minor

Wilson’s PhalaropePhalaropus tricolor

Red-necked PhalaropePhalaropus lobatus

Red PhalaropePhalaropus fulicarius

Family Glareolidae – Pratincoles

Oriental PratincoleGlareola maldivarum

Family Laridae – Gulls and Terns

Swallow-tailed GullCreagrus furcatus

Black-legged KittiwakeRissa tridactyla

Two subspecies (Pacific and Atlantic) are distinguished by average differences in wingtip pattern and voice, but probably not identifiable in the field.

Red-legged KittiwakeRissa brevirostris

Ivory GullPagophila eburnea

Sabine’s GullXema sabini

Bonaparte’s GullChroicocephalus philadelphia

Gray-hooded GullChroicocephalus cirrocephalus

Black-headed GullChroicocephalus ridibundus

Little GullHydrocoloeus minutus

Ross’s GullRhodostethia rosea

Laughing GullLeucophaeus atricilla

Franklin’s GullLeucophaeus pipixcan

Belcher’s GullLarus belcheri

Black-tailed GullLarus crassirostris

Heermann’s GullLarus heermanni

Mew GullLarus canus

Three subspecies. The American Mew Gull is distinctive, especially in immature plumage, and is often split from the others. Kamchatka and Common Gull are fairly distinct from each other and usually identifiable in the field.

Mew Gull (European or Common Gull) – Larus canus canus group *

Mew Gull (Kamchatka or Siberian) – Larus canus kamtschatschensis

Mew Gull (Short-billed or American) – Larus canus brachyrhynchus *

Ring-billed GullLarus delawarensis

Western GullLarus occidentalis

Two subspecies differ only in average shade of gray on the mantle and average size, and are not reliably identified in the field

Yellow-footed GullLarus livens

California GullLarus californicus

Two subspecies differ only in average size and shade of gray on the mantle and are not reliably identified in the field

Herring GullLarus argentatus

Three subspecies groups are all fairly distinctive and usually identifiable (with very careful study) in the field, but most distinctive in juvenal plumage. Many authorities now split them into three species.

Herring Gull (American or Smithsonian) – Larus argentatus smithsonianus

Herring Gull (Vega or Siberian) – Larus argentatus vegae

Herring Gull (European) – Larus argentatus argentatus group

Yellow-legged GullLarus michahellis

Thayer’s GullLarus thayeri

Iceland GullLarus glaucoides

Two subspecies differ in average wingtip pattern and average size, but overlap in all features makes field identification essentially impossible in North America, where the white-winged subspecies L. g. glaucoides is probably a rare visitor but is apparently matched by some pale L. g. kumlieni

Lesser Black-backed GullLarus fuscus

Two subspecies have occurred in North America, but differ only in average darkness of adult mantle color, with intermediates, so identification is somewhat tenuous.

Slaty-backed GullLarus schistisagus

Glaucous-winged GullLarus glaucescens

Siberian breeders differ at least from Washington breeders in long call, and possibly in average adult leg color and mantle color. More study is needed to determine the extent and geographic pattern of differences.

Glaucous GullLarus hyperboreus

Average regional differences in size and mantle color are not sufficient for reliable identificiton out of range.

Great Black-backed GullLarus marinus

Kelp GullLarus dominicanus

Brown NoddyAnous stolidus

Black NoddyAnous minutus

Sooty TernOnychoprion fuscatus

Bridled TernOnychoprion anaethetus

Aleutian TernOnychoprion aleuticus

Least TernSternula antillarum

Large-billed TernPhaetusa simplex

Gull-billed TernGelochelidon nilotica

Caspian TernHydroprogne caspia

Black TernChlidonias niger

White-winged TernChlidonias leucopterus

Whiskered TernChlidonias hybrida

Roseate TernSterna dougallii

Common TernSterna hirundo

Two subspecies are probably reliably identified by bill and leg color in breeding plumage but not at other times. Asian a rare visitor to western Alaska.

Common Tern (Western or American/European) – Sterna hirundo hirundo

Common Tern (Asian) – Sterna hirundo longipennis

Arctic TernSterna paradisaea

Forster’s TernSterna forsteri

Royal TernThalasseus maximus

Sandwich TernThalasseus sandvicensis

Two subspecies reliably identified by bill color, although mixed breeding colonies in the Caribbean suggest that these might be considered morphs. European populations recently split by some authorities as Sandwich Tern T. sandvicensis, and could occur in North America (one potential record from Illinois).

Sandwich Tern (American or Cabot’s) – Thalasseus sandvicensis acuflavidus

Sandwich Tern (Cayenne Tern) – Thalasseus sandvicensis eurygnathus

Elegant TernThalasseus elegans

Black SkimmerRynchops niger

Family Stercorariidae – Skuas and Jaegers

Great SkuaStercorarius skua

The AOU still lumps the Antarctic skuas in this species. Those are split by most authorities as Brown Skua C. antarcticus with confirmed records (by DNA) in Britain, and suspected records off eastern US.

South Polar SkuaStercorarius maccormicki

Pomarine JaegerStercorarius pomarinus

Parasitic JaegerStercorarius parasiticus

Long-tailed JaegerStercorarius longicaudus

Family Alcidae – Alcids

DovekieAlle alle

Common MurreUria aalge

Pacific and Atlantic populations differ in bill shape, but whether this would be sufficient to identify a bird out-of-range is unknown.

Thick-billed MurreUria lomvia

Pacific and Atlantic populations differ in bill shape, but whether this would be sufficient to identify a bird out-of-range is unknown.

RazorbillAlca torda

Black GuillemotCepphus grylle

Two subspecies differ in overall color in non-breeding plumages, but how reliably these can be distinguished is unknown.

Black Guillemot (Arctic) – Cepphus grylle mandtii

Black Guillemot (Atlantic) – Cepphus grylle arcticus group

Pigeon GuillemotCepphus columba

Long-billed MurreletBrachyramphus perdix

Marbled MurreletBrachyramphus marmoratus

Kittlitz’s MurreletBrachyramphus brevirostris

Xantus’s MurreletSynthliboramphus hypoleucus

Two subspecies differ in plumage and voice and are always readily identified.

Xantus’ Murrelet (Northern or Scripps’s) – Synthliboramphus hypoleucus scrippsi *

Xantus’ Murrelet (Southern) – Synthliboramphus hypoleucus hypoleucus *

Craveri’s MurreletSynthliboramphus craveri

Ancient MurreletSynthliboramphus antiquus

Cassin’s AukletPtychoramphus aleuticus

Parakeet AukletAethia psittacula

Least AukletAethia pusilla

Whiskered AukletAethia pygmaea

Crested AukletAethia cristatella

Rhinoceros AukletCerorhinca monocerata

Atlantic PuffinFratercula arctica

Horned PuffinFratercula corniculata

Tufted PuffinFratercula cirrhata

Family Columbidae – Pigeons and Doves

Rock PigeonColumba livia

Scaly-naped PigeonPatagioenas squamosa

White-crowned PigeonPatagioenas leucocephala

Red-billed PigeonPatagioenas flavirostris

Band-tailed PigeonPatagioenas fasciata

European Turtle-DoveStreptopelia turtur

Oriental Turtle-DoveStreptopelia orientalis

Eurasian Collared-DoveStreptopelia decaocto

Spotted DoveStreptopelia chinensis

White-winged DoveZenaida asiatica

Zenaida DoveZenaida aurita

Mourning DoveZenaida macroura

Inca DoveColumbina inca

Common Ground-DoveColumbina passerina

Eastern and Western subspecies differ only on average in overall plumage color, and are too variable to allow identification outside their normal range.

Ruddy Ground-DoveColumbina talpacoti

Eastern and Western subspecies differ only on average in overall plumage color. Some extremes might be identifiable but color is so variable with age and sex that most probably cannot be identified to subspecies outside their normal range.

White-tipped DoveLeptotila verreauxi

Key West Quail-DoveGeotrygon chrysia

Ruddy Quail-DoveGeotrygon montana

Family Psittacidae – Parrots

BudgerigarMelopsittacus undulatus

Monk ParakeetMyiopsitta monachus

Green ParakeetAratinga holochlora

Thick-billed ParrotRhynchopsitta pachyrhyncha

White-winged ParakeetBrotogeris versicolurus

Red-crowned ParrotAmazona viridigenalis

Family Cuculidae – Cuckoos

Common CuckooCuculus canorus

Oriental CuckooCuculus optatus

Yellow-billed CuckooCoccyzus americanus

Mangrove CuckooCoccyzus minor

Black-billed CuckooCoccyzus erythropthalmus

Greater RoadrunnerGeococcyx californianus

Smooth-billed AniCrotophaga ani

Groove-billed AniCrotophaga sulcirostris

Family Tytonidae – Barn Owls

Barn OwlTyto alba

Family Strigidae – Typical Owls

Flammulated OwlOtus flammeolus

Oriental Scops-OwlOtus sunia

Western Screech-OwlMegascops kennicottii

Subspecies variation appears to be clinal, involving size and average color, but a recent DNA barcode study revealed substantial differences between some populations. More study is needed.

Eastern Screech-OwlMegascops asio

Subspecies variation is clinal, involving size and average color, although it has been suggested that the South Texas population might be more distinctive, with slightly different vocalizations.

Whiskered Screech-OwlMegascops trichopsis

Great Horned OwlBubo virginianus

Subspecies variation is clinal, mostly involving average color. In any specific location it should be possible to identify a visitor from a nearby region, and some subspecies are fairly distinctive, but more study is needed to define any regional groups.

Snowy OwlBubo scandiacus

Northern Hawk OwlSurnia ulula

Northern Pygmy-OwlGlaucidium gnoma

Three subspecies groups differ in voice and only very slightly in plumage and size. These have been proposed for splitting but more info is needed on the extent and reliability of differences.

Northern Pygmy-Owl (Mexican or Mountain) – Glaucidium gnoma gnoma

Northern Pygmy-Owl (Pacific) – Glaucidium gnoma californicum group

Northern Pygmy-Owl (Interior West or Mountain) – Glaucidium gnoma pinicola group

Ferruginous Pygmy-OwlGlaucidium brasilianum

Elf OwlMicrathene whitneyi

Burrowing OwlAthene cunicularia

Two subspecies are readily identified by plumage.

Burrowing Owl (Western) – Athene cunicularia hypugaea

Burrowing Owl (Florida) – Athene cunicularia floridana

Mottled OwlCiccaba virgata

Spotted OwlStrix occidentalis

Two subspecies groups differ in overall plumage color and DNA, probably barely identifiable.

Spotted Owl (Northern) – Strix occidentalis occidentalis group

Spotted Owl (Mexican) – Strix occidentalis lucida

Barred OwlStrix varia

Great Gray OwlStrix nebulosa

Long-eared OwlAsio otus

Stygian OwlAsio stygius

Short-eared OwlAsio flammeus

Two subspecies readily identified by plumage. Other subspecies occur outside North America.

Short-eared Owl (Northern) – Asio flammeus flammeus *

Short-eared Owl (Antillean) – Asio flammeus domingensis group *

Boreal OwlAegolius funereus

Siberian form recorded once in Alaska (Pribilof Islands, Jan 1911) much paler than American and probably readily distinguished in the field, and DNA barcode study shows substantial difference from North American.

Boreal Owl (Tengmalm’s or Siberian) – Aegolius funereus magnus

Boreal Owl (American) – Aegolius funereus richardsoni

Northern Saw-whet OwlAegolius acadicus

No known variation in most of North America but the Queen Charlotte Islands, BC, population is distinctly darker and might be recognizable in the field.

Brown Hawk-OwlNinox scutulata

Family Caprimulgidae – Nightjars

Lesser NighthawkChordeiles acutipennis

Common NighthawkChordeiles minor

Subspecies differ in size and average color, but only the juvenal plumage of Great Plains birds is distinctive enough to be identifiable.

Common Nighthawk (Typical) – Chordeiles minor minor group

Common Nighthawk (Plains) – Chordeiles minor sennetti group

Antillean NighthawkChordeiles gundlachii

Common PauraqueNyctidromus albicollis

Common PoorwillPhalaenoptilus nuttallii

Chuck-will’s-widowCaprimulgus carolinensis

Buff-collared NightjarCaprimulgus ridgwayi

Eastern Whip-poor-willCaprimulgus vociferus

Mexican Whip-poor-willCaprimulgus arizonae

Gray NightjarCaprimulgus indicus

Family Apodidae – Swifts

Black SwiftCypseloides niger

White-collared SwiftStreptoprocne zonaris

Chimney SwiftChaetura pelagica

Vaux’s SwiftChaetura vauxi

Two subspecies (Mexican subspecies C. v. tamaulipensis a very rare visitor to the US) are readily distinguished in the hand. Identifying them in the field will be more difficult, but should be possible. ––Read more…

Vaux’s Swift (Northern) – Chaetura vauxi vauxi

Vaux’s Swift (Mexican) – Chaetura vauxi tamaulipensis [richmondi group]

White-throated NeedletailHirundapus caudacutus

Common SwiftApus apus

Fork-tailed SwiftApus pacificus

White-throated SwiftAeronautes saxatalis

Antillean Palm-SwiftTachornis phoenicobia

Family Trochilidae – Hummingbirds

Green VioletearColibri thalassinus

Green-breasted MangoAnthracothorax prevostii

Broad-billed HummingbirdCynanthus latirostris

White-eared HummingbirdHylocharis leucotis

Xantus’s HummingbirdHylocharis xantusii

Berylline HummingbirdAmazilia beryllina

Buff-bellied HummingbirdAmazilia yucatanensis

Cinnamon HummingbirdAmazilia rutila

Violet-crowned HummingbirdAmazilia violiceps

Blue-throated HummingbirdLampornis clemenciae

Magnificent HummingbirdEugenes fulgens

Plain-capped StarthroatHeliomaster constantii

Bahama WoodstarCalliphlox evelynae

Lucifer HummingbirdCalothorax lucifer

Ruby-throated HummingbirdArchilochus colubris

Black-chinned HummingbirdArchilochus alexandri

Anna’s HummingbirdCalypte anna

Costa’s HummingbirdCalypte costae

Calliope HummingbirdStellula calliope

Bumblebee HummingbirdAtthis heloisa

Broad-tailed HummingbirdSelasphorus platycercus

Rufous HummingbirdSelasphorus rufus

Allen’s HummingbirdSelasphorus sasin

Birds of the Channel Islands and adjacent mainland average longer-billed with little overlap (sex for sex) but no other differences are known, intergradation probably occurs northwards, and it is generally not possible to identify this subspecies in the field.

Family Trogonidae – Trogons

Eared QuetzalEuptilotis neoxenus

Elegant TrogonTrogon elegans

Family Upupidae – Hoopoes

Eurasian HoopoeUpupa epops

Family Alcedinidae – Kingfishers

Ringed KingfisherMegaceryle torquata

Belted KingfisherMegaceryle alcyon

Amazon KingfisherChloroceryle amazona

Green KingfisherChloroceryle americana

Family Picidae – Woodpeckers

Eurasian WryneckJynx torquilla

Lewis’s WoodpeckerMelanerpes lewis

Red-headed WoodpeckerMelanerpes erythrocephalus

Acorn WoodpeckerMelanerpes formicivorus

Subtle differences in average size and plumage might be sufficient to allow identification of subspecies in the field, but more study is needed to assess variation. No differences in voice are known.

Acorn Woodpecker (Pacific) – Melanerpes formicivorus bairdi

Acorn Woodpecker (Southwestern) – Melanerpes formicivorus formicivorus group

Gila WoodpeckerMelanerpes uropygialis

Golden-fronted WoodpeckerMelanerpes aurifrons

Red-bellied WoodpeckerMelanerpes carolinus

Birds of southern Florida differ on average in size and plumage, and may appear quite different from far northern birds, but variation is reportedly extensive and clinal, and some authorities do not even recognize a separate subspecies there. More study is needed to clarify the situation.

Williamson’s SapsuckerSphyrapicus thyroideus

Yellow-bellied SapsuckerSphyrapicus varius

Red-naped SapsuckerSphyrapicus nuchalis

Red-breasted SapsuckerSphyrapicus ruber

Two subspecies usually identifiable by plumage color.

Red-breasted Sapsucker (Northern) – Sphyrapicus ruber ruber

Red-breasted Sapsucker (Southern) – Sphyrapicus ruber daggetti

Great Spotted WoodpeckerDendrocopos major

Ladder-backed WoodpeckerPicoides scalaris

Nuttall’s WoodpeckerPicoides nuttallii

Downy WoodpeckerPicoides pubescens

Three subspecies groups differ in plumage, but not voice or structure; many are probably identifiable but reliability of differences needs to be worked out.

Downy Woodpecker (Eastern) – Picoides pubescens pubescens group

Downy Woodpecker (Interior West) – Picoides pubescens leucurus group

Downy Woodpecker (Pacific) – Picoides pubescens gairdnerii group

Hairy WoodpeckerPicoides villosus

Four subspecies groups differ in plumage, and slightly in size, but not voice or structure; many are probably safely identifiable but reliability of differences needs to be worked out.

Hairy Woodpecker (Interior West) – Picoides villosus septentrionalis group

Hairy Woodpecker (Eastern) – Picoides villosus villosus group

Hairy Woodpecker (Pacific) – Picoides villosus harrisi group

Hairy Woodpecker (Mexican) – Picoides villosus icastus

Arizona WoodpeckerPicoides arizonae

Red-cockaded WoodpeckerPicoides borealis

White-headed WoodpeckerPicoides albolarvatus

American Three-toed WoodpeckerPicoides dorsalis

Three subspecies differ in overall darkness of plumage on average, but variation probably renders them unidentifiable in most cases.

Black-backed WoodpeckerPicoides arcticus

Northern FlickerColaptes auratus

Two populations reliably distinguished by multiple plumage differences, but intergrades are common across a very wide area.

Northern Flicker (Yellow-shafted) – Colaptes auratus auratus group

Northern Flicker (Red-shafted) – Colaptes auratus cafer group

Gilded FlickerColaptes chrysoides

Pileated WoodpeckerDryocopus pileatus

Family Tyrannidae – Tyrant Flycatchers

Northern Beardless-TyrannuletCamptostoma imberbe

Greenish ElaeniaMyiopagis viridicata

White-crested ElaeniaElaenia albiceps

Tufted FlycatcherMitrephanes phaeocercus

Olive-sided FlycatcherContopus cooperi

Breeders in southern California show slight average differences in size and plumage, but probably not sufficient for identification in the field. Birds of entire Pacific region (currently not distinguished as a subspecies) migrate much earlier in spring and seem to differ slightly in song from Taiga birds. More study is needed.

Greater PeweeContopus pertinax

Western Wood-PeweeContopus sordidulus

Eastern Wood-PeweeContopus virens

Cuban PeweeContopus caribaeus

Yellow-bellied FlycatcherEmpidonax flaviventris

Acadian FlycatcherEmpidonax virescens

Alder FlycatcherEmpidonax alnorum

Willow FlycatcherEmpidonax traillii

Two groups may be distinguishable in the field, with subtle differences in plumage and possibly in voice. More study is needed to determine the reliability of ID features.

Willow Flycatcher (Eastern) – Empidonax traillii traillii group

Willow Flycatcher (Western) – Empidonax traillii brewsteri group

Least FlycatcherEmpidonax minimus

Hammond’s FlycatcherEmpidonax hammondii

Gray FlycatcherEmpidonax wrightii

Dusky FlycatcherEmpidonax oberholseri

Pacific-slope FlycatcherEmpidonax difficilis

Channel Islands population differs very slightly in average color and song, but probably not safely identifiable in the field. In fact, recent evidence suggests that this species and Cordilleran Flycatcher – while distinctive in the southern (allopatric) parts of their ranges – intermix broadly in the north and might be better lumped as one species – Western Flycatcher.

Cordilleran FlycatcherEmpidonax occidentalis

Buff-breasted FlycatcherEmpidonax fulvifrons

Black PhoebeSayornis nigricans

Eastern PhoebeSayornis phoebe

Say’s PhoebeSayornis saya

Vermilion FlycatcherPyrocephalus rubinus

Dusky-capped FlycatcherMyiarchus tuberculifer

Two subspecies (Eastern a rare visitor to Texas) are reliably distinguished by plumage.

Dusky-capped Flycatcher (West Mexican) – Myiarchus tuberculifer olivascens

Dusky-capped Flycatcher (East Mexican) – Myiarchus tuberculifer lawrenceii

Ash-throated FlycatcherMyiarchus cinerascens

Nutting’s FlycatcherMyiarchus nuttingi

Great Crested FlycatcherMyiarchus crinitus

Brown-crested FlycatcherMyiarchus tyrannulus

Western Mexican and Eastern Mexican populations differ only in average size (especially bill size) and are not safely identified in the field.

La Sagra’s FlycatcherMyiarchus sagrae

Great KiskadeePitangus sulphuratus

Social FlycatcherMyiozetetes similis

Sulphur-bellied FlycatcherMyiodynastes luteiventris

Piratic FlycatcherLegatus leucophaius

Variegated FlycatcherEmpidonomus varius

Crowned Slaty FlycatcherEmpidonomus aurantioatrocristatus

Tropical KingbirdTyrannus melancholicus

Nominate subspecies of South America (recorded once in California and should be watched for elsewhere) differs in plumage color and might just be distinguishable in the field.

Couch’s KingbirdTyrannus couchii

Cassin’s KingbirdTyrannus vociferans

Thick-billed KingbirdTyrannus crassirostris

Western KingbirdTyrannus verticalis

Eastern KingbirdTyrannus tyrannus

Gray KingbirdTyrannus dominicensis

Loggerhead KingbirdTyrannus caudifasciatus

Scissor-tailed FlycatcherTyrannus forficatus

Fork-tailed FlycatcherTyrannus savana

Most North American records involve the South American subspecies, but a few have been identified as Mexican. Differences involve plumage, primary tip shape of male, and presumably molt timing, but reliability of these differences needs to be established.

Fork-tailed Flycatcher (South American) – Tyrannus savana savana group

Fork-tailed Flycatcher (Mexican) – Tyrannus savana monachus

Masked TityraTityra semifasciata

Gray-collared BecardPachyramphus major

Rose-throated BecardPachyramphus aglaiae

Two subspecies are probably reliably separated by plumage, but this needs confirmation. Other subspecies farther south in Mexico intergrade.

Rose-throated Becard (West Mexican) – Pachyramphus aglaiae albiventris

Rose-throated Becard (East Mexican) – Pachyramphus aglaiae gravis

Family Laniidae – Shrikes

Brown ShrikeLanius cristatus

Loggerhead ShrikeLanius ludovicianus

Subspecies show slight and average differences in plumage, probably not reliably identifiable in the field.

Northern ShrikeLanius excubitor

Siberian form recorded once in western Aleutians. More study is needed on visual ID criteria, but DNA barcode study shows substantial difference from North American.

Northern Shrike (American) – Lanius excubitor borealis group

Northern Shrike (Siberian or Great Grey) – Lanius excubitor sibiricus

Family Vireonidae – Vireos

White-eyed VireoVireo griseus

Three subspecies in US differ in average size and plumage brightness. It is possible that some might be identifiable, but more study is needed.

Thick-billed VireoVireo crassirostris

Bell’s VireoVireo bellii

Two subspecies groups appear to be reliably distinguished by plumage, shape, and behavior.

Bell’s Vireo (Eastern) – Vireo bellii bellii

Bell’s Vireo (Southwestern) – Vireo bellii pusillus group

Black-capped VireoVireo atricapilla

Gray VireoVireo vicinior

Yellow-throated VireoVireo flavifrons

Plumbeous VireoVireo plumbeus

Cassin’s VireoVireo cassinii

Blue-headed VireoVireo solitarius

Hutton’s VireoVireo huttoni

Two subspecies groups differ in overall plumage color and differ slightly in voice, but identification in the field would be a challenge.

Hutton’s Vireo (Pacific) – Vireo huttoni huttoni group

Hutton’s Vireo (Mexican) – Vireo huttoni stephensi group

Warbling VireoVireo gilvus

Two subspecies groups differ on average in plumage, size, song, and DNA, and have often been discussed as potential species; but reliability of differences still has not been established and the possibility of identification in the field needs more study.

Warbling Vireo (Eastern) – Vireo gilvus gilvus

Warbling Vireo (Western) – Vireo gilvus swainsoni group

Philadelphia VireoVireo philadelphicus

Red-eyed VireoVireo olivaceus

Yellow-green VireoVireo flavoviridis

Black-whiskered VireoVireo altiloquus

Yucatan VireoVireo magister

Family Corvidae – Crows and Jays

Gray JayPerisoreus canadensis

Three subspecies groups differ in plumage, and are identifiable in most cases, but intergrade where ranges meet. More study might reveal additional and more reliable differences.

Gray Jay (Taiga) – Perisoreus canadensis canadensis group

Gray Jay (Mountain) – Perisoreus canadensis capitalis group

Gray Jay (Pacific) – Perisoreus canadensis obscurus group

Steller’s JayCyanocitta stelleri

Many named subspecies can be grouped in several different ways but variation is mostly clinal with many intergrades and no groups are very well-defined. Two subspecies groups listed here differ in plumage, and are identifiable in most cases. When study is limited to a single region it is often possible to identify a resident population and several different visiting forms. More study might reveal additional and more reliable differences.

Steller’s Jay (Pacific) – Cyanocitta stelleri stelleri group

Steller’s Jay (Mountain) – Cyanocitta stelleri diademata group

Blue JayCyanocitta cristata

Green JayCyanocorax yncas

Brown JayPsilorhinus morio

Florida Scrub-JayAphelocoma coerulescens

Island Scrub-JayAphelocoma insularis

Western Scrub-JayAphelocoma californica

Two subspecies groups differ consistently in plumage and slightly in voice and behavior. Proposed as full species.

Western Scrub-Jay (Pacific) – Aphelocoma californica californica group *

Western Scrub-Jay (Interior West or Woodhouse’s) – Aphelocoma californica woodhouseii group *

Mexican JayAphelocoma ultramarina

Two subspecies groups differ consistently in plumage and juvenile bill color, and slightly in voice and behavior. Could be considered for species status but connected by intermediate populations through Mexico.

Mexican Jay (Arizona) – Aphelocoma ultramarina arizonae [wollweberi group] *

Mexican Jay (Texas or Couch’s) – Aphelocoma ultramarina couchii group *

Pinyon JayGymnorhinus cyanocephalus

Black-billed MagpiePica hudsonia

Yellow-billed MagpiePica nuttalli

Clark’s NutcrackerNucifraga columbiana

Eurasian JackdawCorvus monedula

American CrowCorvus brachyrhynchos

Northwestern CrowCorvus caurinus

Tamaulipas CrowCorvus imparatus

Fish CrowCorvus ossifragus

Chihuahuan RavenCorvus cryptoleucus

Common RavenCorvus corax

Recent DNA studies reveal a significantly different population in California, which may also differ in size and proportions, but whether or not that form is identifiable in the field remains to be worked out.

Family Alaudidae – Larks

Sky LarkAlauda arvensis

Introduced populations in British Columbia originated in England, while vagrants from Siberia have occurred in Alaska and very rarely farther south on the Pacific coast. The two might be reliably distinguishable by plumage.

Horned LarkEremophila alpestris

There are certainly several identifiable forms within this species. Similar to, for example, Great Horned Owl, variation is clinal and involves plumage color. A cursory grouping is offered here based on the Sibley Guide but a full and detailed review is needed.

Horned Lark (Asian) – Eremophila alpestris flava

Horned Lark (Western Arctic) – Eremophila alpestris alpestris group

Horned Lark (Northeastern) – Eremophila alpestris praticola

Horned Lark (East Mexican) – Eremophila alpestris giraudi

Horned Lark (Interior West) – Eremophila alpestris leucolaema

Horned Lark (West Mexican) – Eremophila alpestris occidentalis

Horned Lark (Pacific Northwest) – Eremophila alpestris strigata group

Horned Lark (California) – Eremophila alpestris rubea

Family Hirundinidae – Swallows and Martins

Northern Rough-winged SwallowStelgidopteryx serripennis

Purple MartinProgne subis

Two subspecies groups differ in non-adult-male plumages, and may differ in voice. More study is needed to determine how reliably these can be distinguished in the field, and whether Southwestern desert birds belong with other western populations or as a separate group.

Purple Martin (Eastern) – Progne subis subis

Purple Martin (Western) – Progne subis hesperia group

Cuban MartinProgne cryptoleuca

Gray-breasted MartinProgne chalybea

Southern MartinProgne elegans

Brown-chested MartinProgne tapera

Tree SwallowTachycineta bicolor

Mangrove SwallowTachycineta albilinea

Violet-green SwallowTachycineta thalassina

Bahama SwallowTachycineta cyaneoviridis

Bank SwallowRiparia riparia

Barn SwallowHirundo rustica

Two subspecies groups differ in plumage and DNA. All or nearly all are readily identifiable. Eurasian group a rare visitor to western Alaska and very rarely farther south.

Barn Swallow (Eurasian) – Hirundo rustica rustica group *

Barn Swallow (American) – Hirundo rustica erythrogaster *

Cliff SwallowPetrochelidon pyrrhonota

Two subspecies groups differ in plumage, timing of breeding. More study is needed but these appear to be readily identifiable. ––Read more…

Cliff Swallow (Northern) – Petrochelidon pyrrhonota pyrrhonota group

Cliff Swallow (Mexican) – Petrochelidon pyrrhonota melanogaster

Cave SwallowPetrochelidon fulva

Mexican and Caribbean groups differ on average in size and color, but variation is so great that it does not seem possible to identify a vagrant in the field with certainty. ––Read more…

Common House-MartinDelichon urbicum

Family Paridae – Chickadees and Titmice

Carolina ChickadeePoecile carolinensis

Black-capped ChickadeePoecile atricapillus

Three general subspecies groups differ in plumage, but intergrade where ranges meet. Birds of the Pacific coast are most distinctive and might be reliably identifable.

Mountain ChickadeePoecile gambeli

Two subspecies groups recently proposed for species status differ in DNA, but only slightly in plumage and proportions. Reliability of differences need to be determined but identification in the field will be difficult. ––Read more…

Mountain Chickadee (Interior West) – Poecile gambeli gambeli group

Mountain Chickadee (Pacific) – Poecile gambeli baileyae group

Mexican ChickadeePoecile sclateri

Chestnut-backed ChickadeePoecile rufescens

Two groups differ in plumage and are relatively distinctive. Intergrades occur in a limited area. ––Read more…

Chestnut-backed Chickadee (Northern) – Poecile rufescens rufescens

Chestnut-backed Chickadee (California) – Poecile rufescens barlowi group

Boreal ChickadeePoecile hudsonicus

Two groups – Eastern (Brown-backed) and Western (Gray-backed) – can be distinguished by average plumage color, but the reliability of differences needs to be determined.

Gray-headed ChickadeePoecile cinctus

Bridled TitmouseBaeolophus wollweberi

Oak TitmouseBaeolophus inornatus

Juniper TitmouseBaeolophus ridgwayi

Tufted TitmouseBaeolophus bicolor

Black-crested TitmouseBaeolophus atricristatus

Family Remizidae – Verdin

VerdinAuriparus flaviceps

Family Aegithalidae – Bushtit

BushtitPsaltriparus minimus

Two subspecies groups differ in plumage and are reliably distinguished in virtually all cases. The “Black-eared” Bushtit is merely a color morph of Interior subspecies, found mainly south of the US.

Bushtit (Pacific) – Psaltriparus minimus minimus group *

Bushtit (Interior West) – Psaltriparus minimus plumbeus [melanotis group] *

Family Sittidae – Nuthatches

Red-breasted NuthatchSitta canadensis

White-breasted NuthatchSitta carolinensis

Three subspecies groups differ in plumage, bill shape, and voice, and are reliably distinguishable in the field. Recent DNA studies reveal a fourth group in eastern Sierra Nevada, which needs clarification.

White-breasted Nuthatch (Eastern) – Sitta carolinensis carolinensis *

White-breasted Nuthatch (Rocky Mountain) – Sitta carolinensis mexicana group *

White-breasted Nuthatch (Pacific) – Sitta carolinensis aculeata group *

Pygmy NuthatchSitta pygmaea

Three subspecies in North America differ in head color, flank color, and average size and might be identifiable in the field. Some California populations reportedly differ in voice. More study is needed.

Brown-headed NuthatchSitta pusilla

Family Certhiidae – Creepers

Brown CreeperCerthia americana

Four subspecies groups differ slightly in plumage and song. Recent studies reveal substantial differences in DNA, and suggest that at least the Mexican form (which is most distinctive in plumage and song and probably reliably identified in the field) should be split. ––Read more…

Brown Creeper (Pacific) – Certhia americana occidentalis group

Brown Creeper (Rocky Mountain) – Certhia americana montana group

Brown Creeper (Eastern) – Certhia americana americana group

Brown Creeper (Mexican) – Certhia americana albescens *

Family Troglodytidae – Wrens

Cactus WrenCampylorhynchus brunneicapillus

Two subspecies groups differ in plumage and slightly in voice, and should be reliably distinguished in the field.

Cactus Wren (Mexican) – Campylorhynchus brunneicapillus anthonyi [brunneicapillus group] *

Cactus Wren (California) – Campylorhynchus brunneicapillus sandiegensis [affinis group] *

Rock WrenSalpinctes obsoletus

Canyon WrenCatherpes mexicanus

Sinaloa WrenThryothorus sinaloa

Carolina WrenThryothorus ludovicianus

Mexican population might be identifiable by plumage and song, but variation might be broadly clinal; more study is needed to assess differences and the extent of intergradation with Northern birds.

Bewick’s WrenThryomanes bewickii

Three subspecies groups differ in plumage, song, an DNA, but apparently intergrade where ranges meet.

Bewick’s Wren (Eastern) – Thryomanes bewickii bewickii group

Bewick’s Wren (Southwestern) – Thryomanes bewickii eremophilus [mexicanus group]

Bewick’s Wren (Pacific) – Thryomanes bewickii spilurus group

House WrenTroglodytes aedon

The Mexican (Brown-throated) population might qualify as an identifiable form, but birds in the US are reportedly intergrades between the distinctive form farther south and US birds. Eastern and Western forms differ very slightly in plumage and voice but are probably not reliably identified in the field.

House Wren (Northern) – Troglodytes aedon aedon group

House Wren (Mexican or Brown-throated) – Troglodytes aedon cahooni

Winter WrenTroglodytes hiemalis

Pacific WrenTroglodytes pacificus

Alaskan populations differ in size and overall color, and extremes are probably identifiable but much of the variation is clinal.

Pacific Wren (Alaska) – Troglodytes pacificus alascensis group

Pacific Wren (Southern) – Troglodytes pacificus pacificus group

Sedge WrenCistothorus platensis

Marsh WrenCistothorus palustris

Eastern and Western populations differ substantially and consistently in song and singing behavior, and differ slightly in plumage and have been proposed for species status. In addition, Pacific birds differ at least in overall color from other Western birds, and a distinctively gray subspecies occurs in coastal southeast US.

Marsh Wren (Western) – Cistothorus palustris paludicola group *

Marsh Wren (Eastern) – Cistothorus palustris palustris group *

Family Polioptilidae – Gnatcatchers

Blue-gray GnatcatcherPolioptila caerulea

Two subspecies differ slightly in plumage and voice and might be reliably identified out of range, more study is needed.

Blue-gray Gnatcatcher (Eastern) – Polioptila caerulea caerulea

Blue-gray Gnatcatcher (Western) – Polioptila caerulea amoenissima [obscura group]

California GnatcatcherPolioptila californica

Black-tailed GnatcatcherPolioptila melanura

Eastern and Western forms are usually distinguishable by tail pattern, and more study might reveal other differences.

Black-tailed Gnatcatcher (Western or Sonoran) – Polioptila melanura lucida

Black-tailed Gnatcatcher (Eastern or Chihuahuan) – Polioptila melanura melanura

Black-capped GnatcatcherPolioptila nigriceps

Family Cinclidae – Dippers

American DipperCinclus mexicanus

Family Pycnonotidae – Bulbuls

Red-whiskered BulbulPycnonotus jocosus

Family Regulidae – Kinglets

Golden-crowned KingletRegulus satrapa

Two subspecies groups differ consistently in plumage and should be reliably identifiable in the field (if they can be seen well enough…). Differences recently revealed in DNA of Brown Creeper, White-breasted Nuthatch, and Hairy Woodpecker suggest that Golden-crowned Kinglet might also comprise several distinctive forms. More study is needed!

Golden-crowned Kinglet (Western) – Regulus satrapa olivaceus group

Golden-crowned Kinglet (Eastern) – Regulus satrapa satrapa

Ruby-crowned KingletRegulus calendula

Family Phylloscopidae – Leaf Warblers

Willow WarblerPhylloscopus trochilus

Wood WarblerPhylloscopus sibilatrix

Dusky WarblerPhylloscopus fuscatus

Pallas’s Leaf-WarblerPhylloscopus proregulus

Yellow-browed WarblerPhylloscopus inornatus

Arctic WarblerPhylloscopus borealis

Recent research using DNA and song recommends splitting Arctic Warbler into three species. Alaska breeders keep their current name, and Kamchatka Leaf Warbler Phylloscopus examinandus is added to the North American list, as the subspecies xanthodryas is a rare visitor to the Western Aleutians. A third species breeds in Japan and has not been recorded in North America. Field identification of non-singing birds needs to be worked out.

Arctic Warbler (Northern) – Phylloscopus borealis borealis *

Arctic Warbler (Kamchatka Leaf Warbler) – Phylloscopus borealis xanthodryas *

Family Sylviidae

Lesser WhitethroatSylvia curruca

WrentitChamaea fasciata

Family Acrocephalidae

Sedge WarblerAcrocephalus schoenobaenus

Family Megaluridae

Lanceolated WarblerLocustella lanceolata

Middendorff’s Grasshopper-WarblerLocustella ochotensis

Family Muscicapidae – Old World Flycatchers

Spotted FlycatcherMuscicapa striata

Dark-sided FlycatcherMuscicapa sibirica

Gray-streaked FlycatcherMuscicapa griseisticta

Asian Brown FlycatcherMuscicapa dauurica

Narcissus FlycatcherFicedula narcissina

Taiga FlycatcherFicedula albicilla

Family Turdidae – Thrushes

Rufous-tailed RobinLuscinia sibilans

Siberian RubythroatLuscinia calliope

BluethroatLuscinia svecica

Siberian Blue RobinLuscinia cyane

Red-flanked BluetailTarsiger cyanurus

Northern WheatearOenanthe oenanthe

Alaskan and Greenland breeders differ in average size and overall color, but identification in the field is tenuous at best.

StonechatSaxicola torquatus

Eastern BluebirdSialia sialis

Differences in two subspecies groups are slight, despite disjunct range, perhaps not identifiable out of range, but more study is warranted.

Eastern Bluebird (Eastern) – Sialia sialis sialis group

Eastern Bluebird (Mexican) – Sialia sialis fulva [guatemalae group]

Western BluebirdSialia mexicana

Mountain BluebirdSialia currucoides

Townsend’s SolitaireMyadestes townsendi

Brown-backed SolitaireMyadestes occidentalis

Orange-billed Nightingale-ThrushCatharus aurantiirostris

Black-headed Nightingale-ThrushCatharus mexicanus

VeeryCatharus fuscescens

Subspecies show only slight and average differences in overall color and are not safely identified in the field.

Gray-cheeked ThrushCatharus minimus

Bicknell’s ThrushCatharus bicknelli

Swainson’s ThrushCatharus ustulatus

Two subspecies groups differ consistently in plumage and slightly in song, also have different winter range and migration timing. These should be reliably identifiable in the field, but extent of any intergradation needs to be determined, and the Western Mountain populations (appearance like Taiga birds) need to be studied.

Swainson’s Thrush (Pacific or Russet-backed) – Catharus ustulatus ustulatus group *

Swainson’s Thrush (Taiga or Olive-backed) – Catharus ustulatus swainsoni *

Hermit ThrushCatharus guttatus

Three subspecies groups reliably distinguished in the field by plumage, size, and voice. Some intermediate populations make identification more challenging, but most individuals should be relatively easy to classify.

Hermit Thrush (Pacific) – Catharus guttatus guttatus group *

Hermit Thrush (Interior West) – Catharus guttatus auduboni group *

Hermit Thrush (Taiga) – Catharus guttatus faxoni group *

Wood ThrushHylocichla mustelina

Eurasian BlackbirdTurdus merula

Eyebrowed ThrushTurdus obscurus

Dusky ThrushTurdus eunomus

Naumann’s ThrushTurdus naumanni

FieldfareTurdus pilaris

RedwingTurdus iliacus

Song ThrushTurdus philomelos

Clay-colored ThrushTurdus grayi

White-throated ThrushTurdus assimilis

Rufous-backed RobinTurdus rufopalliatus

American RobinTurdus migratorius

Variation is slight and clinal, with much overlap, and no subspecies are reliably identifiable. ––Read more…

Varied ThrushIxoreus naevius

Aztec ThrushRidgwayia pinicola

Family Mimidae – Mockingbirds and Thrashers

Gray CatbirdDumetella carolinensis

Northern MockingbirdMimus polyglottos

Bahama MockingbirdMimus gundlachii

Sage ThrasherOreoscoptes montanus

Brown ThrasherToxostoma rufum

Long-billed ThrasherToxostoma longirostre

Bendire’s ThrasherToxostoma bendirei

Curve-billed ThrasherToxostoma curvirostre

Two subspecies groups differ in plumage and DNA, and slightly in voice. Most should be reliably identified, but some conflicting evidence in the contact zone gives reason for caution. ––Read more…

Curve-billed Thrasher (Texas or Chihuahuan) – Toxostoma curvirostre curvirostre group *

Curve-billed Thrasher (Arizona or Sonoran or Palmer’s) – Toxostoma curvirostre palmeri group *

California ThrasherToxostoma redivivum

Crissal ThrasherToxostoma crissale

Le Conte’s ThrasherToxostoma lecontei

Blue MockingbirdMelanotis caerulescens

Family Sturnidae – Starlings and Mynas

Common Hill MynaGracula religiosa

Common MynaAcridotheres tristis

European StarlingSturnus vulgaris

Family Prunellidae – Accentors

Siberian AccentorPrunella montanella

Family Motacillidae – Wagtails and Pipits

Eastern Yellow WagtailMotacilla tschutschensis

Two subspecies (Kamchatka a rare visitor to western Alaska) differ in plumage and many/most are probably reliably separated in adult male plumage, but intergradation and variation need to be assessed. Some authorities split these into two species.

Eastern Yellow Wagtail (Siberian) – Motacilla tschutschensis tschutschensis

Eastern Yellow Wagtail (Kamchatka) – Motacilla tschutschensis simillima

Citrine WagtailMotacilla citreola

Gray WagtailMotacilla cinerea

White WagtailMotacilla alba

Three subspecies groups all reliably distinguished in the field (although Black-backed and Siberian are barely distinguishable from each other in non-adult-male plumages). Only Siberian occurs regularly in North America.

White Wagtail (European) – Motacilla alba alba group

White Wagtail (Siberian) – Motacilla alba ocularis

White Wagtail (Black-backed ) – Motacilla alba lugens

Tree PipitAnthus trivialis

Olive-backed PipitAnthus hodgsoni

Pechora PipitAnthus gustavi

Red-throated PipitAnthus cervinus

American PipitAnthus rubescens

Two subspecies groups more or less reliably distinguished. Although both are quite variable and there is overlap in all identifying characteristics, the sum of differences makes most Asian birds readily distinguishable from American.

American Pipit (Asian) – Anthus rubescens japonicus

American Pipit (Buff-bellied Pipit) – Anthus rubescens rubescens group

Sprague’s PipitAnthus spragueii

Family Bombycillidae – Waxwings

Bohemian WaxwingBombycilla garrulus

Two subspecies (Asian a very rare visitor) should be reliably distinguished by plumage, although differences involve merely saturation of colors and not pattern, so identifying a bird far out-of-range might be tenuous.

Bohemian Waxwing (American) – Bombycilla garrulus pallidiceps

Bohemian Waxwing (Asian) – Bombycilla garrulus centralasiae

Cedar WaxwingBombycilla cedrorum

Family Ptilogonatidae – Silky-Flycatchers

Gray Silky-flycatcherPtilogonys cinereus

PhainopeplaPhainopepla nitens

Family Peucedramidae – Olive Warbler

Olive WarblerPeucedramus taeniatus

Family Calcariidae – Longspurs

McCown’s LongspurRhynchophanes mccownii

Lapland LongspurCalcarius lapponicus

Smith’s LongspurCalcarius pictus

Chestnut-collared LongspurCalcarius ornatus

Snow BuntingPlectrophenax nivalis

Subspecies townsendi of western Alaska averages larger and whiter than widespread nivalis, but differences are probably not sufficient to allow identification, and intergrades occur.

McKay’s BuntingPlectrophenax hyperboreus

Family Parulidae – Wood Warblers

Blue-winged WarblerVermivora cyanoptera

Golden-winged WarblerVermivora chrysoptera

Tennessee WarblerOreothlypis peregrina

Orange-crowned WarblerOreothlypis celata

Four subspecies groups may sometimes be distinguishable in the field. It may be possible to identify at least Pacific (V. c. lutescens) with certainty in the field, but differences are small and need clarification.

Orange-crowned Warbler (Taiga) – Vermivora celata celata

Orange-crowned Warbler (Interior West ) – Vermivora celata orestera

Orange-crowned Warbler (Pacific) – Vermivora celata lutescens

Orange-crowned Warbler (Channel Islands ) – Vermivora celata sordida

Nashville WarblerOreothlypis ruficapilla

Differences in song, plumage, and possibly tail movements (as well as DNA) between eastern and western populations may be sufficient for field identification, but this has not yet been confirmed.

Nashville Warbler (Eastern) – Vermivora ruficapilla ruficapilla

Nashville Warbler (Western or Calaveras) – Vermivora ruficapilla ridgwayi

Virginia’s WarblerOreothlypis virginiae

Colima WarblerOreothlypis crissalis

Lucy’s WarblerOreothlypis luciae

Crescent-chested WarblerParula superciliosa

Northern ParulaParula americana

Subtle differences in song between Eastern and Western populations of this species are probably not reliable enough to allow confident identification.

Tropical ParulaParula pitiayumi

Yellow WarblerDendroica petechia

Three major groups are distinctive. Within the Northern group it is often possible to identify migrants as belonging to, for example, a northern population based on drab color and/or timing of migration, but this is not enough to allow a subspecies label. Golden and Mangrove populations are both distinctive and identifiable.

Yellow Warbler (Northern) – Dendroica petechia aestiva group *

Yellow Warbler (Mangrove) – Dendroica petechia erithachorides group *

Yellow Warbler (Golden) – Dendroica petechia gundlachi [petechia group] *

Chestnut-sided WarblerDendroica pensylvanica

Magnolia WarblerDendroica magnolia

Cape May WarblerDendroica tigrina

Black-throated Blue WarblerDendroica caerulescens

Two populations (Northern and Appalachian) differ on average in adult male plumage, but extensive intergradation and variation makes this difference almost meaningless.

Yellow-rumped WarblerDendroica coronata

Two populations often considered separate species; identifiable in all plumages by multiple features, as well as by call note. Audubon’s includes two other distinctive forms south of the US and might be split further.

Yellow-rumped Warbler (Myrtle or Taiga) – Dendroica coronata coronata group *

Yellow-rumped Warbler (Audubon’s or Western) – Dendroica coronata auduboni group *

Black-throated Gray WarblerDendroica nigrescens

A substantial difference in DNA between coastal and interior populations, but no known difference in plumage or voice. More study is warranted.

Golden-cheeked WarblerDendroica chrysoparia

Black-throated Green WarblerDendroica virens

Townsend’s WarblerDendroica townsendi

Hermit WarblerDendroica occidentalis

Blackburnian WarblerDendroica fusca

Yellow-throated WarblerDendroica dominica

Coastal and Interior forms differ slightly in plumage and bill length, but extensive variation makes identification of many birds uncertain. An extralimital population in the Bahamas has recently been elevated to species status.

Grace’s WarblerDendroica graciae

Pine WarblerDendroica pinus

Kirtland’s WarblerDendroica kirtlandii

Prairie WarblerDendroica discolor

Northern and Florida populations differ slightly in plumage color and have no overlap in breeding range. Currently not considered field identifiable but more study is warranted.

Palm WarblerDendroica palmarum

Two populations nearly always distinguishable by overall color.

Palm Warbler (Brown) – Dendroica palmarum palmarum

Palm Warbler (Yellow) – Dendroica palmarum hypochrysea

Bay-breasted WarblerDendroica castanea

Blackpoll WarblerDendroica striata

Cerulean WarblerDendroica cerulea

Black-and-white WarblerMniotilta varia

American RedstartSetophaga ruticilla

Prothonotary WarblerProtonotaria citrea

Worm-eating WarblerHelmitheros vermivorum

Swainson’s WarblerLimnothlypis swainsonii

OvenbirdSeiurus aurocapilla

Northern WaterthrushParkesia noveboracensis

Louisiana WaterthrushParkesia motacilla

Kentucky WarblerOporornis formosus

Connecticut WarblerOporornis agilis

Mourning WarblerOporornis philadelphia

MacGillivray’s WarblerOporornis tolmiei

Common YellowthroatGeothlypis trichas

Several identifiable forms must be contained within Common Yellowthroat. A rough grouping is listed here, but more study is needed to sort out differences in plumage and song.

Common Yellowthroat (Pacific) – Geothlypis trichas arizela group

Common Yellowthroat (Interior West) – Geothlypis trichas occidentalis group

Common Yellowthroat (Eastern) – Geothlypis trichas trichas group

Common Yellowthroat (Southwestern) – Geothlypis trichas chryseola group

Bahama YellowthroatGeothlypis rostrata

Gray-crowned YellowthroatGeothlypis poliocephala

Hooded WarblerWilsonia citrina

Wilson’s WarblerWilsonia pusilla

Pacific and Taiga forms differ enough in plumage and perhaps voice to be recognizable, although many intergrades and an intermediate population (W. p. pileolata in the Interior West cloud the issue.

Wilson’s Warbler (Taiga) – Wilsonia pusilla pusilla

Wilson’s Warbler (Pacific) – Wilsonia pusilla chryseola

Canada WarblerWilsonia canadensis

Red-faced WarblerCardellina rubrifrons

Painted RedstartMyioborus pictus

Slate-throated RedstartMyioborus miniatus

Fan-tailed WarblerEuthlypis lachrymosa

Golden-crowned WarblerBasileuterus culicivorus

Rufous-capped WarblerBasileuterus rufifrons

Eastern and Western Mexican subspecies differ slightly in plumage and might be reliably identifiable.

Yellow-breasted ChatIcteria virens

Family Genus Incertae Sedis (Bananaquit)

BananaquitCoereba flaveola

Family Thraupidae – Tanagers

Western SpindalisSpindalis zena

Two subspecies from the Bahamas are reliably distinguished by adult male plumage and have been recorded in Florida. Another subspecies from Cuba may also occur.

Western Spindalis (Southern Bahamas or Green-backed) – Spindalis zena zena

Western Spindalis (Northern Bahamas or Black-backed) – Spindalis zena townsendi

Western Spindalis (Cuban) – Spindalis zena pretrei

Red-legged HoneycreeperCyanerpes cyaneus

Family Emberizidae – New World Sparrows

White-collared SeedeaterSporophila torqueola

The bright Cinnamon-rumped form from West Mexico has been recorded several times from California, Arizona, and Texas. All are suspected of being escapes but regardless of that males are easily identifiable in the field.

White-collared Seedeater (East Mexican) – Sporophila torqueola morelleti group

White-collared Seedeater (Cinnamon-rumped or West Mexican) – Sporophila torqueola torqueola

Yellow-faced GrassquitTiaris olivaceus

Black-faced GrassquitTiaris bicolor

Olive SparrowArremonops rufivirgatus

Green-tailed TowheePipilo chlorurus

Spotted TowheePipilo maculatus

Three subspecies groups differ in plumage and voice, but plumage, song, and call seem to vary independently to some extent, and this arrangement is certainly not the best. More study is needed.

Spotted Towhee (Pacific) – Pipilo maculatus oregonus group

Spotted Towhee (Great Plains) – Pipilo maculatus arcticus group

Spotted Towhee (Southwestern) – Pipilo maculatus montanus group

Eastern TowheePipilo erythrophthalmus

Populations in the southeast differ from northern birds in eye color and slightly in plumage, but intergrade broadly so that variation is mostly clinal.

Canyon TowheeMelozone fusca

California TowheeMelozone crissalis

Abert’s TowheeMelozone aberti

Rufous-winged SparrowPeucaea carpalis

Cassin’s SparrowPeucaea cassinii

Bachman’s SparrowPeucaea aestivalis

Variation in upperparts color are fairly obvious, but clinal, and it is doubtful that any of the three subspecies could be reliably identified out of range.

Botteri’s SparrowPeucaea botterii

Two subspecies differ fairly strongly in upperparts color, and would probably be identifiable out of range. No other differences are known.

Botteri’s Sparrow (Western) – Peucaea botterii arizonae

Botteri’s Sparrow (Eastern) – Peucaea botterii texana

Rufous-crowned SparrowAimophila ruficeps

Two subspecies groups differ slightly in plumage and size. Most are probably reliably identified in the field but more study is needed.

Rufous-crowned Sparrow (Pacific) – Aimophila ruficeps ruficeps group

Rufous-crowned Sparrow (Interior) – Aimophila ruficeps scottii group

Five-striped SparrowAmphispiza quinquestriata

American Tree SparrowSpizella arborea

Chipping SparrowSpizella passerina

Clay-colored SparrowSpizella pallida

Brewer’s SparrowSpizella breweri

Two subspecies differ on average in plumage and size, slightly in song and DNA. Often proposed for species status, the field identification of these two forms still remains to be worked out.

Brewer’s Sparrow (Southern) – Spizella breweri breweri *

Brewer’s Sparrow (Timberline) – Spizella breweri taverneri *

Field SparrowSpizella pusilla

Worthen’s SparrowSpizella wortheni

Black-chinned SparrowSpizella atrogularis

Vesper SparrowPooecetes gramineus

Lark SparrowChondestes grammacus

Black-throated SparrowAmphispiza bilineata

Two subspecies groups (Western and Texas) differ slightly in overall color, tail pattern, and size, but more study is needed to clarify potential differences.

Sage SparrowAmphispiza belli

Two subspecies groups differ consistently in plumage and song and are reliably identified in the field.

Sage Sparrow (Pacific or Bell’s) – Amphispiza belli belli group *

Sage Sparrow (Interior) – Amphispiza belli nevadensis *

Lark BuntingCalamospiza melanocorys

Savannah SparrowPasserculus sandwichensis

Widespread Continental forms vary slightly in plumage and size, but are generally not distinguishable from each other in the field. Ipswich, Belding’s, and Large-billed are all reliably identified, although intermediate populations and/or intergrades cloud the issue. In addition to plumage, differences in bill size, crown shape, and timing of breeding are useful. ––Read more…

Savannah Sparrow (Ipswich) – Passerculus sandwichensis princeps *

Savannah Sparrow (Continental) – Passerculus sandwichensis sandwichensis group *

Savannah Sparrow (Belding’s) – Passerculus sandwichensis beldingi [guttatus group] *

Savannah Sparrow (Large-billed) – Passerculus sandwichensis rostratus group *

Grasshopper SparrowAmmodramus savannarum

Four subspecies. Differences in plumage might allow confident identification of some individuals in the field, but on current knowledge none are considered identifiable.

Baird’s SparrowAmmodramus bairdii

Henslow’s SparrowAmmodramus henslowii

Le Conte’s SparrowAmmodramus leconteii

Nelson’s SparrowAmmodramus nelsoni

Two subspecies groups differ consistently in plumage and are reliably identified.

Nelson’s Sparrow (Interior) – Ammodramus nelsoni nelsoni group *

Nelson’s Sparrow (Atlantic or Acadian) – Ammodramus nelsoni subvirgatus *

Saltmarsh SparrowAmmodramus caudacutus

Seaside SparrowAmmodramus maritimus

Three subspecies groups differ in plumage and are probably reliably identifiable in the field, although considerable variation and multiple subspecies within both Atlantic and Gulf Coast populations might complicate identification. The distinctive Dusky Seaside Sparrow is extinct.

Seaside Sparrow (Atlantic) – Ammodramus maritimus maritimus group

Seaside Sparrow (Dusky) – Ammodramus maritimus nigrescens

Seaside Sparrow (Gulf Coast) – Ammodramus maritimus sennetti group

Seaside Sparrow (Cape Sable) – Ammodramus maritimus mirabilis

Fox SparrowPasserella iliaca

Four subspecies groups distinguished by plumage, song, calls, and in some cases by size and bill shape. The presence of limited intermediate populations and interbreeding does not affect the ease with which the vast majority of Fox Sparrows can be identified to subspecies group.

Fox Sparrow (Sooty or Pacific) – Passerella iliaca unalaschcensis group *

Fox Sparrow (Thick-billed or California) – Passerella iliaca megarhyncha group *

Fox Sparrow (Slate-colored or Interior West) – Passerella iliaca schistacea group *

Fox Sparrow (Red or Taiga) – Passerella iliaca iliaca group *

Song SparrowMelospiza melodia

Extensive variation across its wide range can be partitioned loosely into the forms listed here, but variation is mostly clinal and all forms intergrade. Similar to Horned Lark and others, there are certainly better ways to subdivide the species, but more study is needed.

Song Sparrow (Aleutian) – Melospiza melodia sanaka group

Song Sparrow (Pacific Northwest) – Melospiza melodia rufina group

Song Sparrow (California) – Melospiza melodia samuelis group

Song Sparrow (Southwestern) – Melospiza melodia fallax group

Song Sparrow (Eastern) – Melospiza melodia melodia group

Lincoln’s SparrowMelospiza lincolnii

Swamp SparrowMelospiza georgiana

Subspecies nigrescens on mid-Atlantic coast might be identifiable, at least in breeding plumage, but subtle differences in plumage require testing.

White-throated SparrowZonotrichia albicollis

Harris’s SparrowZonotrichia querula

White-crowned SparrowZonotrichia leucophrys

Best considered three identifiable forms, with Taiga group including pale-lored birds in the west and dark-lored in the east. Pacific is distinctive and always readily identifiable. Mountain and Taiga intergrade across a broad area, and Mountain is very similar to Eastern Taiga birds, but most should be identifiable by plumage and voice. ––Read more…

White-crowned Sparrow (Taiga or Gambel’s) – Zonotrichia leucophrys leucophrys group

White-crowned Sparrow (Mountain) – Zonotrichia leucophrys oriantha

White-crowned Sparrow (Pacific or Nuttall’s) – Zonotrichia leucophrys nuttalli group

Golden-crowned SparrowZonotrichia atricapilla

Dark-eyed JuncoJunco hyemalis

Six forms can be identified with confidence in the field, even though intergrades occur wherever ranges overlap. A broad intergrade zone between Slate-colored and Oregon in the Canadian Rockies produces a variable population, while farther north and west an apparently stable intermediate form is found which could be listed as a seventh identifiable population. More study is needed to clarify extent of intergradation and slight differences in songs and calls.

Dark-eyed Junco (Slate-colored ) – Junco hyemalis hyemalis group

Dark-eyed Junco (Oregon) – Junco hyemalis oreganus group

Dark-eyed Junco (Pink-sided) – Junco hyemalis mearnsi

Dark-eyed Junco (White-winged) – Junco hyemalis aikeni

Dark-eyed Junco (Gray-headed) – Junco hyemalis caniceps

Dark-eyed Junco (Red-backed) – Junco hyemalis dorsalis

Yellow-eyed JuncoJunco phaeonotus

Pine BuntingEmberiza leucocephalos

Yellow-browed BuntingEmberiza chrysophrys

Little BuntingEmberiza pusilla

Rustic BuntingEmberiza rustica

Yellow-throated BuntingEmberiza elegans

Yellow-breasted BuntingEmberiza aureola

Gray BuntingEmberiza variabilis

Pallas’s BuntingEmberiza pallasi

Reed BuntingEmberiza schoeniclus

Family Cardinalidae – Cardinals and Buntings

Hepatic TanagerPiranga flava

Summer TanagerPiranga rubra

Two subspecies might be distinguished in the field by bill size and plumage color; more study is needed.

Summer Tanager (Western or Cooper’s) – Piranga rubra cooperi group

Summer Tanager (Eastern) – Piranga rubra rubra

Scarlet TanagerPiranga olivacea

Western TanagerPiranga ludoviciana

Flame-colored TanagerPiranga bidentata

Two subspecies probably occur (West Mexican a rare visitor to Arizona, East Mexican form possibly a rare visitor to Texas, but this needs confirmation). Adult males and possibly adult females are fairly distinctive based on plumage color.

Flame-colored Tanager (West Mexican) – Piranga bidentata bidentata

Flame-colored Tanager (East Mexican) – Piranga bidentata sanguinolenta

Crimson-collared GrosbeakRhodothraupis celaeno

Northern CardinalCardinalis cardinalis

Two subspecies groups are reliably distinguished by bill shape and plumage pattern.

Northern Cardinal (Southwestern) – Cardinalis cardinalis superbus group

Northern Cardinal (Eastern) – Cardinalis cardinalis cardinalis group

PyrrhuloxiaCardinalis sinuatus

Yellow GrosbeakPheucticus chrysopeplus

Rose-breasted GrosbeakPheucticus ludovicianus

Black-headed GrosbeakPheucticus melanocephalus

Blue BuntingCyanocompsa parellina

Blue GrosbeakPasserina caerulea

Lazuli BuntingPasserina amoena

Indigo BuntingPasserina cyanea

Varied BuntingPasserina versicolor

Painted BuntingPasserina ciris

DickcisselSpiza americana

Family Icteridae – Orioles and Blackbirds

BobolinkDolichonyx oryzivorus

Red-winged BlackbirdAgelaius phoeniceus

Two subspecies groups represent extremes of variation and are reliably distinguished by plumage and differ slightly in song, but intermediate populations exist. Populations in southern Florida may differ in song and plumage and deserve more study.

Red-winged Blackbird (Typical) – Agelaius phoeniceus phoeniceus group

Red-winged Blackbird (Bicolored) – Agelaius phoeniceus californicus group

Tricolored BlackbirdAgelaius tricolor

Tawny-shouldered BlackbirdAgelaius humeralis

Eastern MeadowlarkSturnella magna

Two subspecies groups can apparently be distinguished by plumage color and voice, although identifying either within the range of the other would be extremely difficult.

Eastern Meadowlark (Eastern) – Sturnella magna magna group

Eastern Meadowlark (Lilian’s) – Sturnella magna lilianae

Western MeadowlarkSturnella neglecta

Yellow-headed BlackbirdXanthocephalus xanthocephalus

Rusty BlackbirdEuphagus carolinus

Brewer’s BlackbirdEuphagus cyanocephalus

Common GrackleQuiscalus quiscula

Two subspecies groups are reliably identified in adult male plumage, somewhat less distinctive in females. Many intergrades occur in a relatively narrow band where ranges meet from Louisiana to New England.

Common Grackle (Purple) – Quiscalus quiscula quiscula group

Common Grackle (Bronzed) – Quiscalus quiscula versicolor

Boat-tailed GrackleQuiscalus major

Iris color varies regionally, but no other significant differences are known.

Great-tailed GrackleQuiscalus mexicanus

Populations west of southeastern Arizona differ slightly in size, female plumage color, and possibly voice, and differ significantly in DNA, from birds farther east. These may be identifiable (they have even been suggested as possible species) but more study is needed to work out identification criteria and to assess an apparent contact zone in southeastern Arizona.

Shiny CowbirdMolothrus bonariensis

Bronzed CowbirdMolothrus aeneus

Eastern and Western populations are quite different in female plumage, and several flight call variations are also known. More study is needed to sort out differences.

Bronzed Cowbird (Western) – Molothrus aeneus loyei group

Bronzed Cowbird (Eastern) – Molothrus aeneus aeneus

Brown-headed CowbirdMolothrus ater

Differences in flight calls and in gape color of juveniles might allow identification of subspecies. More study is needed.

Brown-headed Cowbird (Western) – Molothrus ater artemisiae group

Brown-headed Cowbird (Eastern) – Molothrus ater ater

Black-vented OrioleIcterus wagleri

Orchard OrioleIcterus spurius

The East Mexican form (Fuertes’s Oriole) is very distinctive in adult male plumage, recorded once in Texas. Sometimes considered a distinct species.

Orchard Oriole (Northern) – Icterus spurius spurius

Orchard Oriole (Fuertes’s) – Icterus spurius fuertesi

Hooded OrioleIcterus cucullatus

Eastern and Western populations differ in intensity of male plumage, but intergrade broadly and, given the variation shown in carotenoid pigments in plumage of birds, are probably not safely identified by this feature alone.

Streak-backed OrioleIcterus pustulatus

Bullock’s OrioleIcterus bullockii

Spot-breasted OrioleIcterus pectoralis

Altamira OrioleIcterus gularis

Audubon’s OrioleIcterus graduacauda

Baltimore OrioleIcterus galbula

Scott’s OrioleIcterus parisorum

Family Fringillidae – Finches

Common ChaffinchFringilla coelebs

BramblingFringilla montifringilla

Gray-crowned Rosy-FinchLeucosticte tephrocotis

Four subspecies groups are identifiable by plumage and size. Listed here as four groups, but these could also be sorted into two groups: Gray-cheeked (Bering Sea, Aleutian, and Coastal) and Brown-cheeked (Interior).

Gray-crowned Rosy-Finch (Bering Sea ) – Leucosticte tephrocotis umbrina

Gray-crowned Rosy-Finch (Aleutian) – Leucosticte tephrocotis griseonucha

Gray-crowned Rosy-Finch (Gray-cheeked or Hepburn’s or Coastal) – Leucosticte tephrocotis littoralis

Gray-crowned Rosy-Finch (Interior) – Leucosticte tephrocotis tephrocotis group

Black Rosy-FinchLeucosticte atrata

Brown-capped Rosy-FinchLeucosticte australis

Pine GrosbeakPinicola enucleator

Several subspecies groups are identifiable by plumage, size and flight call, but more study is needed to sort out variation and assess intermediate populations. Kamchatka subspecies recorded several times in western Alaska differs substantially from North American populations in DNA barcode test.

Pine Grosbeak (Kamchatka) – Pinicola enucleator kamtschatkensis

Pine Grosbeak (Pacific) – Pinicola enucleator flammula group

Pine Grosbeak (Interior West) – Pinicola enucleator montana group

Pine Grosbeak (Taiga) – Pinicola enucleator leucura group

Common RosefinchCarpodacus erythrinus

Purple FinchCarpodacus purpureus

Two subspecies are nearly always distinguishable by plumage, structure, and voice, with limited intergradation. ––Read more…

Purple Finch (Eastern) – Carpodacus purpureus purpureus *

Purple Finch (California) – Carpodacus purpureus californicus *

Cassin’s FinchCarpodacus cassinii

House FinchCarpodacus mexicanus

Oriental GreenfinchChloris sinica

Red CrossbillLoxia curvirostra

Ten different call types now known and nearly always identifiable by analysis of recordings, also differ very slightly in bill size and shape. ––Read more…

White-winged CrossbillLoxia leucoptera

Common RedpollAcanthis flammea

Two subspecies distinguishable by size and average differences in color. Most are probably safely identified, although these subspecies are quite poorly-known. ––Read more…

Common Redpoll (Southern) – Acanthis flammea flammea

Common Redpoll (Greater or Greenland) – Acanthis flammea rostrata

Hoary RedpollAcanthis hornemanni

Two subspecies distinguishable by size and average difference in color. Most are probably safely identified, although these subspecies are quite poorly-known. ––Read more…

Hoary Redpoll (Southern) – Acanthis hornemanni exilipes

Hoary Redpoll (Hornemann’s or Greenland) – Acanthis hornemanni hornemanni

Eurasian SiskinSpinus spinus

Pine SiskinSpinus pinus

Lesser GoldfinchSpinus psaltria

Adult males occur in two distinctive forms – Black-backed and Green-backed – that show strong geographic basis, but variation and the occurrence of each type well within the range of the other suggests that this color difference represents a morph rather than a subspecific difference.

Lawrence’s GoldfinchSpinus lawrencei

American GoldfinchSpinus tristis

Eastern and Western (and perhaps Pacific) forms differ slightly in plumage and possibly voice. These are probably not safely identified in the field but more study is warranted.

Eurasian BullfinchPyrrhula pyrrhula

Evening GrosbeakCoccothraustes vespertinus

Four forms are distinguishable by flight calls, more or less matching named subspecies, but more study is needed to clarify differences and to match vocal types with plumage and bill size variation.

HawfinchCoccothraustes coccothraustes

Family Passeridae – Old World Sparrows

House SparrowPasser domesticus

Eurasian Tree SparrowPasser montanus

Family Estrildidae – Waxbills, Munias, and allies

Nutmeg MannikinLonchura punctulata

38 thoughts on “Field Identifiable Subspecies of birds – an annotated list”

  1. Isn’t the Hepburn’s Gray-crowned Rosy-Finch the coastal group? What about grouping them by overall plumage color (brownish/blackish) rather than cheek color?

    eBird and Clements suggest the name Woodhouse’s Western Scrub-Jay for the interior groups based on the latin trinomial.

    From what I’ve read (and also eBird and Clements) the Northern Pygmy-Owl subspecies G. g. gnoma is already referred to as the Mountain Pgymy-Owl, Not Mexican. But Mexican sounds better and more exotic and is probably more accurate.

    1. Thanks Matt, I’ve updated English names on these. It’s too bad if gnoma has acquired the name “Mountain Pygmy-Owl” because it barely enters the US in Arizona, and the subspecies pinicola is found widely in the mountain west and might differ enough in voice to be recognizable as well.

  2. You left out (maybe intentionally?) waynei Black-throated Green Warblers. Their breeding range (coastal Carolinas and Virginia) is completely different than the nominate ssp and having held skins in my hand, they appear to be identifiable in the field.

    In the past I did a small bit of work for a study looking to get some morphometric data determining precisely what the difference was between a typical virens and a typical waynei, and in the measurements I was taking it appeared that the birds identifiable as waynei are smaller, slighter billed, and with significantly less black on the flanks.

    I never heard what became of that particular data, but it might be one to add to your list.

    1. Thanks Nate. I hadn’t even considered Wayne’s Black-throated Green, but I will definitely check it out.
      And this gives me an opportunity to discuss an inconsistency of subspecies treatment that I’ve wanted to bring up. When naming these identifiable subspecies I tend to “reward” species with limited variation, and “punish” complexity. I’ll use Snow Goose as an example, as it’s a species that I know and that has a pattern of variation similar to Black-throated Green. The Snow Goose is almost uniform in appearance over a wide range, and has one disjunct breeding population (Greater Snow Goose) which looks slightly different. That earned it a place on my list. At the same time I lumped most of the variation in Canada Goose, because there are a lot of different populations varying in size and color, making identification of one individual bird extremely difficult. I think that’s a byproduct of this particular approach to categorizing subspecies, but it also shows up throughout bird taxonomy. I think it has a lot to do with the widespread resistance to the idea of ten species of Red Crossbills. I believe there would be a lot more support for Crossbill splitting if it was only into two or three species.

  3. Surely Buff-bellied Pipit (as used in Europe and Asia for both subspecies) is a better English name than ‘Asian American Pipit’ for Anthus rubescens japonicus?!

    1. I agree. I cringed a little when this name came up, but I am using the official AOU names for species. Hopefully they will change this name soon, because as it stands it doesn’t work for a substantial portion of the species’ range, and birders in Asia are not going to call their pipits “American”. For now it has to be American Pipit, which means that any regional name like Asian or Siberian will be nonsensical.

  4. I’m curious to see Black-backed Oriole on this list. Is there a US record for this species? I don’t see it mentioned for the US in either the AOU nor ABA lists.

    Also, I’m a bit surprised not to see any mention of a few subspecies (and groups) which I thought were relatively field-identifiable. Most notably:
    Scaled Quail (Texan castanogastris vs. the rest)
    Wrentit (northern vs. southern groups)
    Bachman’s Sparrow (illinoiensis vs. the rest)
    Botteri’s Sparrow (arizonae vs. texana)
    Great-tailed Grackle (nelsoni vs. rest: probably two species here!)
    I suppose clinality may obscure the first four cases enough that they may not make the cut, but the last seems to be a pretty solid one. Size, female plumage characters, and voice (especially) all can identify nelsoni Great-tails. A recent molecular phylogeny [Powell et al. 2008. Condor 110(4):718-728] even suggests that they are not sister to the rest of the Great-tailed complex, but are more closely related to the extinct Slender-billed Grackle of the Rio Lerma marshes of DF Mexico.

    1. Hi Dan, Thanks very much for these comments. There is a Black-backed Oriole record in San Diego, CA, (presumably one individual, seen off-and-on from 2000 to 2002) but you are correct that it hasn’t been accepted by any records committee and I will remove it from this list.

      I debated including some of those other species, especially Botteri’s Sparrow and Great-tailed Grackle. My concern about the grackle is that Phillips (1964) described the secondary contact in Arizona in the 1940s and 50s, and implied that interbreeding was common. But now I see that Monson and Phillips (1981) say that monsoni nests in the San Pedro valley and eastwards, with nelsoni in the rest of the state, and only one intermediate population identified! I’ll take a closer look at all of these and update the list soon.

  5. Thanks to all for the comments and suggestions. I’ve just updated the list adding some of Dan Lane’s additional subspecies (but not Wrentit, which seems to show a patchwork of local and clinal variations across California, mostly related to climate). I changed some English and Scientific names based on comments (Special thanks to Richard Klim at BirdForum for tracking down priority names for a bunch of subspecies). And I switched the English names so the subspecies names are in parentheses after the official species name, which seems to be a bit easier to follow (Thanks to Elias Elias for that suggestion). I still see a lot of inconsistent treatment in the list, but I’ll keep working on it and I’m confident that a lot of that can get sorted out over time.

  6. Hi David,

    In reference to:
    Sage Sparrow – Amphispiza belli

    Two subspecies groups differ consistently in plumage and song and are reliably identified in the field.
    Sage Sparrow (Pacific or Bell’s) – Amphispiza belli belli

    Sage Sparrow (Interior) – Amphispiza belli nevadensis group

    As I understand it, Sage Sparrow (nevadensis) is the monotypic form and that Bell’s Sparrow includes belli, clementae, cinerea and, based on recent work by Cicero, the “intermediate” canescens.

    Cicero (2010). The significance of subspecies: a case study of Sage Sparrows. Chapter 9 in Winkler & Haig. Avian Subspecies. Orn. Monographs 67

    Klicka & Banks (2011). A generic name for some sparrows. Zootaxa 2793:67-68.

    Best regards,

    David Donsker

  7. David,

    This is a really helpful resource and tracks well with the groups that we have been working on with eBird and Clements. I’ll continue to look this over in the coming days, but the seabird treatment to me immediately prompts a few comments, especially given the fact that NACC is out of sync with much of the world when it comes to seabird taxonomy (and I’m sure they’d appreciate receiving proposals…it’s not all their fault!).

    1) Yellow-nosed Albatross. The North American records hat are identifiable to subspecies are, not surprisingly, all ‘Atlantic’ Yellow-nosed Albatross (T. c. chlororhynchos), which have gray heads in adult plumage. This is quite different from the white-headed ‘Indian’ Yellow-nosed Albatross (T. c. bassi), and these taxa are split by many authorities.

    2) White-capped Albatross. The NACC has yet to split the Shy Albatross group and still uses the name Shy Albatross. SACC, Clements, and many others are using White-capped, Salvin’s, and Chatham Albatross. Regardless, to be consistent with NACC you should revise the English names to Shy (White-capped) and Shy (Salvin’s). The NACC is behind the times here, but surely is awaiting a proposal.

    3) Black-browed Albatross. While the “first” U.S. record from VA was an immature and tough to identify to subspecies, later photo records (photo of an adult off Newfoundland, and maybe another from Maine) show the expected dark-eyed form T. m. melanophris (or melanophrys, depending on whom you ask) rather than the ‘Campbell’ Black-browed Albatross (T. m. impavida). Again, many accord these forms species status.

    5) The NACC taxonomy for Little Shearwater is extremely outdated and the taxon recorded in North America–Puffinus [assimilis] baroli–was found by Austin et al. 2004 to group with Audubon’s and not with assimilis, which itself needs to be divided several ways. The question remains as to whether baroli would be monotypic (Barolo Shearwater), have two subspecies (including boydi) as Macaronesian Shearwater (as treated by the BOU), or be lumped within Audubon’s, which seems absurd. At the very least this situation deserves a comment like the one you have for Wandering Albatross.

    6) While on the topic of seabirds, it might be worth noting that North American records of Great-winged Petrel refer to gouldi; that Black-capped Petrel sensu NACC includes Jamaican Petrel, te extinct and utterly different dark bird; that North American forms of Audubon’s Shearwater are quite distinct from Galapagos Shearwater, Persian Shearwater, and Tropical Shearwater, which NACC still lumps under Audubon’s; that White-chinned Petrel sensu NACC includes Spectacled Petrel; and that Wilson’s Storm-Petrel may be due for some taxonomic revision, although this may or may not affect the birds that occur in the AOU area. Further, the NACC still lumps Brown Skua under Great Skua, and may be the only authority to do so.

    More to follow, but thanks again for providing this resource!

  8. In response to Marshal Iliff’s first seabird comment above(Yellow-nosed Albatross), I’d be keen to get feedback from Marshall, David, and anyone else with relevant experience on the records from Texas – for which a number of photos of specimens and live birds are displayed at the TBRC web site; they seem to show both gray-headed and white-headed birds, with some subtle differences in bill morphology…? Here’s a link to the page:

  9. Hi Mr. Sibley. I would like to share with you some of my observations regarding Western Gull and Glaucous-Winged Gull:

    Among the subspecies of WEGU, the slightly paler northern birds also seem to average a bit larger. Grant mentioned this in his book as well. Another thing I’ve noticed is the 1st winter (1st basic) northern birds also seem to be a bit grayer, closely resembling the overall tone of same age Herring Gulls. Southern birds this age are browner compared to Herring Gulls as can be seen in this image:

    Among Glaucous-Winged Gulls I’ve made an observation after reading your description on the differences in long calls between Siberian and American (Washington in your example) birds. I noticed a while ago that some Glaucous-Winged Gulls have brighter pink legs than most. After having read you call descriptions, I’ve noticed the birds with the pinker legs almost always have the lower and slower calls you described (many of them are also a bit darker in mantel shade as well). None of this is conclusive of course but just some observations from a long time gull enthusiast. Here is a shot of a bird with the brighter pink legs: This particular bird did have a long call that was noticeably lower and slower than what I was used to hearing. Here’s a more typical bird with duller legs: It also had a more typical call although a bit slower than the birds I heard in Seattle but otherwise was the same.

  10. Hi David,

    Don’t know if this one has been mentioned or not, but I was wondering about subspecific variation in Black-whiskered Vireo(?). The nominate subspecies (Vireo altiloquus altiloquus) seems very distinctive in plumage coloration and bill size/shape to me compared to the coastal Florida form V. a. barbatulus. I believe the nominate subspecies occurs as a causal spring vagrant along the Gulf Coast with records from Louisiana and NW Florida panhandle (St. George Island). I’ve also had some birds here in Alabama in the spring that I highly suspected were probably the nominate form as well.

    Any thoughts?

    Howard Horne
    Mobile, AL

  11. Hi David,

    A great resource, and thank you for putting all this information in one place. I really enjoy learning and looking for these variations in the field. Is there any chance that range maps will be added for these identifiable subspecies? Maybe in your next edition of your NA guide.

    Couple of minor comments, did you mean to include Labrador Duck? And have there been any records of Velvet Scoter in the US or Canada?


    Jim Hully
    Mundelein, IL

    1. Hi Jim, Thanks, I’m glad you find it useful. I do plan to continue adding information about subspecies, with maps, as I find the time. I did not mean to include Labrador Duck, but now that you’ve pointed it out I think I should add all of the extinct or presumed extinct species. There are no North American records of Velvet Scoter.

  12. Hi David,

    I also noticed that you only mention Masked Booby. Wasn’t there at least one record of the eastern Pacific race, S. d. granti, off California (e.g. I remember a juvenile in Monterey Bay in the late 90s), which would now be considered a full species, the Nazca Booby?


    Jim Hully
    Mundelein, IL

    1. Nazca Booby is considered a full species but still no accepted records north of Mexico. I think there was a record in California suspected of being ship-assisted, and some records of immatures that may be Nazca but can’t be identified conclusively.

  13. Hi David,

    Do you know how I can find information on differentiating subspecies? I have seen a Black-crowned Night Heron in the Middle East (subspecies nycticorax) with what seems to be a thicker bill, but I couldn’t find any evidence of this difference with the North American subspecies. Can you help?

    Thank you.

    1. The best references for a starting point on subspecies are Pyle’s Identification Guide to North American Birds, The Handbook of Birds of the Western Palearctic, and the Handbook of Birds of the World. For most species you’ll want to dig deeper into the literature that is cited in those books. I checked Pyle for Black-crowned Night Heron and he lumps the North American and Eurasian birds in one subspecies because there are no reliable differences. In the Middle East you could get other subspecies from either India or Africa, which might be identifiable in the field, but I’m not familiar with the literature on those. [Actually, I just checked the Handbook of Birds of the World and I’m surprised to see that there is only one subspecies listed for all of Europe, Asia, and Africa! So if you see one that looks different it’s probably just a local variant and not a visitor from afar. Sounds to me like a good project for someone to look at DNA and study plumage in detail, because it seems really unlikely that they’re all the same.]

  14. Hi David,
    A while back I wrote to you about a population of Purple Finches that summers on our land in Nova Scotia. Instead of the customary raspberry colour, a large number of the males are yellow. I attached photos of a couple of the many individuals. I can’t find either my letter or a response on your sites. I now wonder if I was successful in posting it.

  15. Hi David,

    thanks for this list. Do you have a list of references for the various subspecies mentioned? I am particularly interested in references for hybridisation amongst subspecies (cline, interbreeding, intergradation, etc.) for the next updates of the Bird Hybrids Database.


    Serge Dumont
    Montréal, Québec

  16. Dear David,

    A wonderful job. Can’t wait for the range maps.

    Erratum: American Coot, annotation – Caribbean
    Question: Wasn’t Xantus’s Murrelet recently split (Scripps’s, Guadalupe)?

  17. I feel that the Larids got short thrift in the above analysis. I could go into detail here if you’d like, but I think that improvements could be made to the entries for B-l Kittiwake, Mew, Herring, Yellow-legged, and LBB Gulls.

  18. David I clearly had nothing to do this afternoon…
    Here are some suggestions:-

    Are there no N. A. records of nominate marila Greater Scaup? If there are, then include in some way.

    Common Eider: your text refers to the “West Arctic” form, but none of the 4 listed ssp. is called this – suggest using either “West Arctic” or “Pacific” in both places.

    Audubon’s Shearwater: according to Howell’s Tubenose book the lone Canadian specimen is attributed to loyermilleri, thus at least 2 subspecies occur in the ABA area. However this form is only distinguishable from Bahamian Audubon’s by measurements and thus probably not worthy of specific mention. However the Lesser Antillean form (true lherminieri if we call the Bahamian birds auduboni) is fairly distinct – at least as distinct as some of the recent splits in this group of Puffinus! – and this form likely (definitely? I have pics from Texas waters of a candidate) occurs in ABA waters.

    Wedge-rumped Storm-Petrel: nominate is the presumed form seen rarely off CA, but the lone U.S. specimen from inland CA is of ssp. kelsalli, which is a potential split per Howell’s Tubenose book.

    Lesser Frigatebird: the ME and MI records probably pertain to ssp. trinitatis while the CA and maybe the WY records pertain to ariel. I don’t know to what extent these forms differ.

    Masked Booby: see precedent set by Snowy Plover; the same format can be used to say that so far all N.A. records are of dactylatra.

    Great Blue Heron: mention “Wurdemann’s – ?

    Turkey Vulture: there are at least two ssp. with described physical differences.

    Spotted Rail: perhaps say that there are two fairly distinguishable ssp possible: the Texas record appears to be the spot-backed insolitus of Mexico and Central America (based on photos of the specimen) while the ssp. of the PA record is unknown (is it?) but more likely to be the streak-backed maculatus from the Caribbean and South America.

    Ditto for Paint-billed Crake: TX specimen IDed as paler, white-throated nominate while VA specimen IDed as darker, gray-throated olivascens.

    Purple Swamphen: mention that some ssps and ssp-groups are considered separate species, and that birds in Florida are of the form ???? (precedent as with Lesser Sand-Plover and Snowy Plover).

    Common Moorhen now Common Gallinule

    Common Ringed Plover: 2 ssp widely recognized (nominate and tundrae)

    Whimbrel: mention that the “American” form is split in Europe as Hudsonian Whimbrel; I recommend that you use “Hudsonian” rather than “American” else you will upset the Canadians!

    Numenius phaeopus phaeopus should be suffixed “(group”) since it includes alboaxillaris.

    Semip. Sand: perhaps mention average differences in bill size geographically, as done with other species?

    Common House-Martin: NE Canada record likely nominate, while AK birds lagopudum (a specimen) that has more extensive white on the rump.

    Arctic Warbler North American ssp. listed as kennicotti in all my references, even as recently as 6th Ed of Nat Geo guide – ?

    Stonechat: follow example of Lesser Sand-Plover: eastern forms, including ssp. maurus often split as Siberian Stonechat. All North American records have been of ssp maurus.

    Gray-cheeked Thrush: mention alicae/minimus, and mention that sp. minimus clouds ID of Bicknell’s away from breeding and wintering grounds).

    Redwing: NE records likely coburni; WA record likely iliacus – don’t know if they are field-separable – ?

    Streak-backed Oriole: The 2 TX records could be from different ssp. than west coast records – ??

    Consider adding the ssp. name for all the polytypic (that are field-discernable in your view) vagrants. If the aim here is to help the viewer know which forms to prepare for in the field, then it would help to know that the Willow Warbler you might find in AK is not going to look exactly like the Willow Warbler in your European FG.

  19. I was wondering, what is Ward’s Heron? I have read old records, that it was in many ways like unto the Great Blue Heron, yet significantly larger, with yellowish legs.

  20. Lovely list. A couple of things, though.

    Had an influx of distinctly different darker-mantled, thinner-billed GW’s arrive after a Siberian cold front arrived in North Vancouver BC. One might have been a Herring X GW, but twenty identical adults arriving on the same day? That Aleutian Arc/Kamchatka Peninsula is clearly an area where larid genetics is pretty volatile.

    Kidding, right? I’ve seen a 1st cycle ‘barrovianus’ Glaucous barely bigger than an adjacent California Gull, and in South Delta BC a huge, presumably ‘pallidus’ Glaucous from Siberia which towered over the nearby GW’s the way a large male Great Black-Backed would dominate the local Herring Gulls. Yet both are called Glaucous Gulls.

  21. Pingback: Brant Waterfowl Wednesday – BirdNation

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