Birds

Mew Gull is now two species! How to identify Common Gull and Short-billed Gull

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 …

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Distinguishing subspecies of Sandhill Crane

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 field observers it’s more practical to assign birds to two subspecies groups: Lesser and Greater. The Greater subspecies group includes five of the named subspecies, …

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Variation in Pine Siskins and the so-called “green morph”

Pine Siskins – streaky relatives of goldfinches – are so distinctive as a species that we tend to overlook their considerable individual variation. Siskins are unusual among the small finches in that males and females look nearly identical. Subtle individual differences in the amount or intensity of streaking, or in overall color, have no bearing …

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Scarlet Tanagers are bright red – but this one is yellow

One of the great pleasures of birding is that you can run into something new and unexpected anytime, anywhere. This summer (June and July 2020) I’ve been birding around my local neighborhood in Deerfield, MA, and even though I’ve lived here for three years now, every day still brings new discoveries. A recent morning produced …

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A Cerulean-like song variant of Black-throated Blue Warbler

This recording includes one song of Cerulean Warbler and one of Black-throated Blue Warbler. Can you tell them apart? Distinguishing Black-throated Blue Warbler and Cerulean Warbler by song is usually not too difficult, even though both have buzzy songs with a more or less rising trend. The typical songs of both species are distinctive, and …

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The head shape of Herring Gulls seems to change seasonally

sketch of gull head shapes

I always enjoy studying Herring Gulls, just looking at variation and trying to categorize the birds into age, sex, and regional groups. Last winter I was watching the gull flock at Turners Falls, MA, paying special attention to when the adults molted into breeding plumage. My thought was that the early-molting birds would be from …

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