Possible? It might be, but most of the widely published “differences” are too subjective and/or too variable to be of any value. I dug into this a couple of years ago and discovered some details that seem more reliable, which are summarized in the one page file here (also as a pdf via this link: […]
Distinguishing Philadelphia and Red-eyed Vireos by song: Is it possible? Read More »
I put together this matrix of variation in breeding plumage Rose-breasted Grosbeaks, showing the differences between each of the four age-sex classes. In this species it’s relatively easy to distinguish males from females, a little harder to distinguish one-year-old males from older males, and nearly impossible to determine the age of females. As in many
Determining age and sex of Rose-breasted Grosbeaks in spring and summer Read More »
The 2023 Clements/eBird taxonomy update has just been announced, and the biggest surprise is that Cattle Egret will now be considered two species! Few people are familiar with variation in Cattle Egret, and while the split won’t have much impact on North American birders I thought it would be helpful to describe the differences. At
Two species of Cattle Egrets? Read More »
In their 2022 checklist supplement the AOS voted to elevate the southwestern populations of Eastern Meadowlark to a full species, with the name Chihuahuan Meadowlark. it’s been recognized as a distinctive population for decades, usually under the name Lilian’s Meadowlark, but making it a full species raises the stakes and adds new emphasis to a
Identification of the newest meadowlark – Chihuahuan Read More »
Common Grackle is a familiar backyard bird almost everywhere east of the Rocky Mountains, and shows some fairly striking regional variation in color. This variation involves mainly the colors of iridescence, and is most obvious in males. Females of the two extremes are readily identified, but the full range of intermediates is only apparent in
Subspecies of Common Grackle: Bronzed, Florida, and “Purple” Read More »
Stejneger’s Scoter is the Siberian counterpart of White-winged Scoter, only recently recognized as a separate species. The two species are very similar in all respects, and only adult males can be identified readily in the field. Stejneger’s is considered a very rare visitor to western Alaska, but my experience in Nome in 2021 suggests that
Finding and Identifying Stejneger’s Scoter in Alaska Read More »
I wanted to know if I could find an objective and reliable feature that would allow me to distinguish any elaenia from any empidonax, and it turns out it’s the pattern on the folded wing. The presence or absence of pale edges on the primaries is the best single feature to focus on to be sure which genus you are looking at.
Identifying small flycatchers: Separating Elaenia and Empidonax by wing pattern Read More »
For North American birders the most consequential change in the 2021 AOS Checklist supplement is the split of Mew Gull into two species – Short-billed Gull and Common Gull. For most birders this simply means changing the name of the species on your list from Mew Gull to Short-billed Gull. The North American population, common
Mew Gull is now two species! How to identify Common Gull and Short-billed Gull Read More »
Prompted by a couple of recent records of Cave Swallows in the northeastern US, I’ve taken a fresh look at subspecies and done some new illustrations. In April 2021 Cave Swallows have been found in New Jersey and Massachusetts. Both have been identified as the Caribbean subspecies group. Since the 1990s Cave Swallow has been
New illustrations of Cave Swallow subspecies Read More »
Mid-March is when the first northbound Fox Sparrows show up in Massachusetts, and it’s always a pleasure to see this burly, richly-colored sparrow. I’ve been working on some new illustrations showing the variation among the birds in my yard this week. Regional variation in Fox Sparrow is extensive, and gets a lot of attention, with
Variation in eastern Fox Sparrows Read More »