The feathers that grow on the sides of the head above the eyes of a bird are called the supercilium, and when they contrast in color with the adjacent feathers we call that an eyebrow stripe. There’s lots of variation in the shape of the eyebrow stripe, and in some closely-related species this can be […]
The changeable shape of the supercilium Read More »
In a previous post I’ve talked about Trumpeter Swans with yellow bill spots as a source of confusion with Tundra Swan. I speculated that the yellow spots might be showing because the birds are leucistic (lacking melanin). The responses to that post are worthy of a follow-up. Harry Lumsden, who has studied the reintroduced Trumpeter
Trumpeter Swans, yellow bill spots, and leucism Read More »
One of the well-defined groups of feathers on the underside of a bird is what we call the breast. In reality, on songbirds these feathers grow from the front of the neck, extending down so that the tips of the feathers (which is all we can see) cover the foreparts of the body – the
Introduction to breast feathers Read More »
A recent discussion about geographic variation in Herring Gulls (on the ID-Frontiers listserve) prompted me to go back and scan some photos I took in 1998 at Cape May. At the time I was sorting out what seemed to be two populations of Herring Gulls, identifiable in their first winter by plumage and shape. There
Variation in immature American Herring Gulls Read More »
As I work on the revision of my field guide I’ve been giving a lot of thought to how the book can assist the process of identification, and what information is most useful to a birder in the field. I’ve settled on the idea that there are two stages of bird identification, each one requiring
The two stages of field identification Read More »
Thanks to reader Anne DuPont for sending in these photos of a pair of Great Blue Herons at Wakodahatchee Wetlands, Delray Beach, Florida. It’s clearly a mated pair, but the female (sexed by behavior) has more white on the head and fore neck, paler legs and bill, white head plumes, paler rust color on the
A Wurdemann’s-like heron from South Florida Read More »
Like many other species of ducks that are distinguished by head shape, Common and Barrow’s Goldeneyes are at least as easy to tell apart when sleeping as when they are awake. Birds that are awake and active change head shape a lot as they go from relaxed to alert to diving, but sleeping birds are
Identifying sleeping female goldeneyes Read More »
For much of the year, distinguishing male and female American Goldfinches is easy (when the males show their brilliant yellow summer plumage, about March through September). Even in January and February many males have a few bright yellow feathers showing, but otherwise the gray-brown nonbreeding males can be hard to tell from females. There is
Distinguishing male and female American Goldfinches Read More »
There are four named subspecies of Scaled Quail, three in the US and one in Mexico. The subspecies found in southern Texas is distinctly different from the other three, at least in adult male plumage, and makes the list of field identifiable subspecies. Here’s a quick summary of the differences, based on study of specimens
Subspecies of Scaled Quail Read More »
A recent discussion on the ID-Frontiers listserver involved an immature gull photographed in Utah (photo by Norman Jenson here). The consensus (and I agree) is that it is a Western Gull based on plumage and shape. But questions arise from the fact that it looks barely larger than the California Gulls next to it –
Do “dwarf” birds exist? Read More »