Last winter’s Common Moorhen in Newfoundland, given the likely split of New World and Old World moorhens into separate species, led me to try to determine the origin of the Newfoundland bird. That study of photos turned up a few small differences in bill color and shape, but nothing fully reliable. Now I have finally […]
The Newfoundland Moorhen was an American based on back color Read More »
I’ve been aware of some variation in songs of Blackpoll Warbler for many years, and now an interesting post by Andrew Spencer at Earbirding prompted me to check into it a little more closely. Many years ago Will Russell pointed out to me that the birds nesting in Alaska all sang a more rapid series
Does Blackpoll Warbler have song dialects? Read More »
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
Three interesting Brant from Massachusetts Read More »
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
Distinguishing Green-winged and Common Teal Read More »
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
About the List of Field Identifiable Subspecies Read More »
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
Distinguishing the subspecies of Purple Finch Read More »