See my detailed discussion of White-crowned subspecies here, which needs updating with the information below. In early May 2011 I spent several days in southeastern Arizona, and devoted a lot of time to studying the White-crowned Sparrows. At that date most of them were migrant Interior West birds of subspecies Z. l. oriantha. Most of …
Distinguishing Interior West from Western Taiga White-crowned Sparrows Read More »
The Mexican Duck was formerly considered a species (Anas diazi), and is currently lumped with Mallard (as subspecies Anas platyrhynchos diazi), but recent DNA studies suggest that Mottled Duck (not Mallard) is its closest relative (McCracken et al. 2001). Whatever its genetic background, it is clear from field observations that Mexican Ducks and Mallards interbreed …
Intergradation between Mexican Duck and Mallard in Arizona Read More »
Note: I’m preparing posts on the range and identification of Brant subspecies, which will help make the following more understandable to those who are not already well-versed in the intricacies of Brant. Over the last fifteen or so years I have seen several odd “gray-bellied” Brant along the US Atlantic coast. This spring I finally …
Identifying subspecies adds richness to your birding by adding another layer of understanding. What’s more, during spring migration, behavior can offer a quick and fairly reliable clue to use when distinguishing local breeders from migrants. This is simply an extension of a bit of advice often given for identifying shorebirds: to watch for birds around …
Identifying subspecies by behavior – Savannah Sparrow Read More »
The Green-winged Teal (known as Common Teal in English-speaking parts of Eurasia) is currently considered a single species by the AOU, but two subspecies are distinctive in adult male plumage and are split into two species by many authorities. Green-winged Teal (American) – Anas crecca carolinensis Common Teal (Eurasian) – Anas crecca crecca ((Common Teal nests in …
The Greater White-fronted Goose (Anser albifrons) occurs throughout much of North America, but is found in largely disjunct populations. Only two North American subspecies are listed by Ely and Dzubin (1994), four by Pyle (2008), but five well-defined “population units” have occurred in North America, and there may be more. Banks (2011) recognizes four of …
Distribution of Greater White-fronted Goose subspecies Read More »
Click here for the complete list of identifiable subspecies of North American birds Some background on subspecies Subspecies are a common focus of debate among birders and ornithologists. The subspecies concept exists as a way to record and classify variation below the species level. The problem is that once we venture below the species level …
Summary The two subspecies of Purple Finch are fairly distinctive with well-defined ranges. They are best distinguished by overall impression of color and pattern, and more objectively by details of back and head pattern. Virtually all individuals should be safely identifiable in the field, but the frequency and extent of intergradation is unknown. Eastern Purple …
Not really. Only under ideal conditions and with reference to location. Mountain Chickadee is found throughout much of the montane coniferous forest of the west, and up to seven subspecies have been described and named. These were sorted by Behle (1956) into Rocky Mountain, Great Basin, and California groups which differ in a complex mosaic …
Can subspecies of Mountain Chickadee be identified in the field? Read More »
Caribbean Coot Fulica caribaea (found sparingly and locally in the West Indies from Hispaniola south and east to the coast of Venezuela) is virtually identical to American Coot except for its all-white frontal shield (Roberson and Baptista, 1988). ((The claim by Brisbin and Mowbray (2002) that American and Caribbean coots can be distinguished by the …