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...
https://www.sibleyguides.com/2023/10/two-species-of-cattle-egrets/
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 ...
https://www.sibleyguides.com/2022/09/identification-of-the-newest-meadowlark-chihuahuan/
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 ...
https://www.sibleyguides.com/2022/05/subspecies-of-common-grackle-bronzed-florida-and-purple/
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 thi...
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 foun...
https://www.sibleyguides.com/2021/04/new-illustrations-of-cave-swallow-subspecies/
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...
https://www.sibleyguides.com/2021/03/variation-in-eastern-fox-sparrows/
Here is another recent project: I’ve been working on new and improved illustrations of Redwing for the bird guide and app, showing the differences between the two subspecies. The Redwing (Turdu...
https://www.sibleyguides.com/2021/03/distinguishing-the-subspecies-of-redwing/
Here’s a new illustration I’ve done as part of some work on distinguishing the two subspecies groups of Sandhill Crane. Six subspecies of Sandhill Crane are generally recognized, but for fiel...
https://www.sibleyguides.com/2021/03/distinguishing-subspecies-of-sandhill-crane/
I wrote about white Great Blue Herons in 2007, and thanks to a recent comment there by David Ammerman alerting me to a whitish Great Blue Heron chick in a nest, I made the short trip to Bolton, M...
https://www.sibleyguides.com/2016/07/white-great-blue-heron-massachusetts/
If you keep up on the news of subspecies, you will have heard of Scopoli’s Shearwater. It’s the Mediterranean breeding population of Cory’s Shearwater, overlapping very little with populat...
https://www.sibleyguides.com/2015/09/underwing-pattern-in-corys-shearwater/