Red-shouldered Hawk Buteo lineatus
     Eastern B. l. lineatus group
     Florida B. l. extimus
     California B. l. elegans

Red-tailed Hawk Buteo jamaicensis
     Eastern B. j. borealis group
     "Krider’s" B. j. ‘kriderii’
     Southwestern B. j. fuertesi
     Western B. j. calurus group
     Harlan’s B. j. harlani

Merlin Falco columbarius
     Taiga F. c. columbarius group
     Prairie F. c. richardsoni
     Black (Pacific) F. c. suckleyi

Peregrine Falcon Falco peregrinus
     Tundra F. p. tundrius
     Interior West F. p. anatum
     Peale’s (Pacific) F. p. pealei

Ring-necked Pheasant Phasianus colchicus
     White-winged P. c.
     Ring-necked P. c.
     European P. c.
     Japanese Green Pheasant P. versicolor

Spruce Grouse Dendragapus canadensis
     Taiga D. c. canadensis group
     Franklin’s D. c. franklinii group

Blue Grouse Dendragapus obscurus
     Pacific D. o. fuliginosus group
     Interior D. o. obscurus group

Rock Ptarmigan Lagopus mutus
     Continental L. m. rupestris group
     Western Aleutian L. m. evermanni group
     Central Aleutian L. m. atkhensis group

Greater Prairie-Chicken Tympanuchus cupido
     Northern T. c. pinnatus
     Attwater’s (Texas) T. c. attwateri

Wild Turkey Meleagris gallopavo
     Eastern M. g. silvestris group
     Southwestern M. g. merriami
The intermediate population found in Texas is named M. g. intermedia.

Northern Bobwhite Colinus virginianus
     Eastern C. v. virginianus
     Florida C. v. floridanus
     Texas C. v. texanus
     Masked C. v. ridgwayi
Various races have been introduced widely, especially virginianus and texanus. These introductions have been largely unsuccesful, although interbreeding with local races may produce broad mixing.

Clapper Rail Rallus longirostris
     Atlantic R. l. crepitans group
     Gulf Coast R. l. saturatus group
     California R. l. obsoletus group (includes levipes and yumanensis)

American Coot Fulica americana
There is no significant variation in the species, but occasional birds (particularly adult males and apparently more in southerly regions) have swollen white frontal shield like Caribbean Coot (Fulica caribaea) of the West Indies. These white-shielded birds should be considered a morph of American Coot. The validity of Caribbean Coot as a species should be investigated more fully.

Sandhill Crane Grus canadensis
     Greater G. c. pratensis group (Widespread subspecies is G. c. tabida)
     Lesser G. c. canadensis
I have lumped all the various southern populations (including Florida and Mississippi G. c. pratensis) under the heading of "Greater". Also included is the intermediate subspecies G. c. rowani of central Canada. Lesser includes only the small northern subspecies G. c. canadensis.

Snowy Plover Charadrius alexandrinus
     Western C. a. nivosus
     Gulf Coast C. a. tenuirostris

Killdeer Charadrius vociferus
Illustrated in the book are two morphs of adults. The one with rufous upper wing coverts seems to occur with greatest frequency in the south (mainly southeast?), and is scarce or absent elsewhere (pers. obs.). Further investigation is needed to determine whether this morph is related to age or sex.

American Oystercatcher Haematopus palliatus
     Eastern H. p. palliatus
     Pacific H. p. frazari

Willet Catoptrophorus semipalmatus
     Western C. s. inornatus
     Eastern C. s. semipalmatus
These two subspecies are distinguished by size, proportions, plumage, and voice. Their breeding ranges are separated by hundreds of miles and they must be considered excellent candidates for splitting.

Whimbrel Numenius phaeopus
     American N. p. hudsonicus
     European N. p. phaeopus group
     Siberian N. p. variegatus

Bar-tailed Godwit Limosa lapponica
European L. l. lapponica
Siberian L. l. baueri

Rock Sandpiper Calidris ptilocnemis
     Pribilof C. p. ptilocnemis
     Aleutian C. p. couesi
     Bering Sea C. p. tschuktschorum

Dunlin Calidris alpina
     American C. a. hudsonia group
     Greenland C. a. alpina group
The Atlantic (hudsonia) and Pacific (pacifica) populations of American Dunlin are apparently fairly distinctive, and a recent DNA study found significant differences between hudsonia and all other Dunlin.

Short-billed Dowitcher Limnodromus griseus
     Atlantic L. g. griseus
     Prairie L. g. hendersoni
     Pacific L. g. caurinus

Common Snipe Gallinago gallinago
     American G. g. delicata
     Eurasian G. g. gallinago group

Mew Gull Larus canus
     Short-billed L. c. brachyrhynchus
     Common L. c. canus group
     Kamchatka L. c. kamchatschensis

California Gull Larus californicus
     southwestern L. c. californicus
     northeastern L. c. albertaensis
These two subspecies are only recently described. Despite described average differences in size there is complete overlap in the range of measurements, and subtle and variable differences in adult mantle color. It is doubtful that these subspecies can be reliably identified in the field.

Herring Gull Larus argentatus
     American L. a. smithsonianus
     European L. a. argentatus/argenteus
     Vega L. a. vegae

Yellow-legged Gull Larus cachinnans
     Mediterranean L. c. michahellis
     Caspian L. c. cachinnans
     Atlantic Island L. c. atlantis
     Of the handful of confirmed records of this species in North America, one specimen is apparently atlantis, other records are apparently michahellis, while one photo record might be cachinnans. Recent evidence strongly supports a split of michahellis and cachinnans into separate species, with atlantis remaining part of michahellis or possibly split as a third species.

Iceland Gull Larus glaucoides
     True Iceland L. g. glaucoides
     Kumlien’s L. g. kumlieni

Lesser Black-backed Gull Larus fuscus
     Britain/Iceland L. f. graellsii
     Denmark L. f. intermedius
There are a handful of documented records of apparent intermedius in North America, but a large population of graellsii x intermedius intergrades (with breeding range centered on the Netherlands) apparently accounts for many of the North American records of this species.

Western Gull Larus occidentalis
     Northern L. o. occidentalis
     Southern L. o. wymani

Glaucous Gull Larus hyperboreus
Subspecies differ in average size and adult mantle color; most individuals cannot be identified to subspecies in the field. The small individuals illustrated are apparently found only in the subspecies L. h. barrovianus, but all subspecies are variable.

Common Tern Sterna hirundo
     American/European L. h. hirundo
     Siberian L. h. longipennis

Common Murre Uria aalge
     Atlantic U. a. aalge
     Pacific U. a. californica

Thick-billed Murre Uria lomvia
     Atlantic U. l. lomvia
     Pacific U. l. arra

Black Guillemot Cepphus grylle
     Atlantic C. g. atlantis group
     Arctic C. g. mandtii group
Although individuals from southeastern areas (e.g. New England) differ significantly from those in Alaska, several intervening subspecies are poorly known and may be intermediate. More study is needed to determine to what extent variation is clinal and whether the several subspecies can conveniently be assigned to two populations.

Xantus' Murrelet Synthliboramphus hypoleucus
     Northern S. h. scrippsi
     Southern S. h. hypoleucus
These two subspecies differ consistently in plumage, measurements, and voice, and reportedly do not interbreed.