The American Ornithological Society (AOS) is the organization that, among many other things, maintains the taxonomic nomenclature of the bird lists of the Americas. For birders like me who keep various lists of the birds they have seen or heard in a geographical area, the decisions made by the AOS can generate great interest.
Birds that are recognized as one species may at some point be split into two distinct species based on compelling research and other factors. The willet, a large shorebird familiar to even casual observers on our coast, may one day be split into the Eastern willet and the Western willet. Both subspecies occur and are common in North Carolina, so when that split occurs all listers will add a willet species to their lists. It’s called an armchair “tick.”
But just as the AOS giveth, the AOS taketh away. Its annual published changes to the Taxonomic Checklist lumped the Thayer’s gull – currently recognized as a distinct species – into the Iceland gull complex. If you have caught on to how this works, you have figured out that many birders, myself included, had their lists where Thayer’s gull appears decrease by one species. The official Mecklenburg County Bird List was reduced by one, too.
A handful of local birders had seen a Thayer’s gull at Lake Norman a few years ago. I was not one of them. Do I feel badly for those who had to strike it from their county or state lists? Not really.
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The Thayer’s gull has been punted around the gull taxonomy so much it must have a severe identity crisis by now. In 1917, the gull was thought to be a pale arctic subspecies of the extensive herring gull complex. In the 1970s, studies suggested Thayer’s gull was a dark subspecies within the Iceland gull complex or was a distinct species altogether. This latter thought prevailed, and Larus thayeri became a thing. For lucky birders who had seen that former subspecies … TICK!
Thayer’s gulls were always very rare in North Carolina. Birders generally had to search through thousands of gulls over the course of many years to find one. They also presented a unique identification challenge, exhibiting much variation between individuals and bearing close resemblance to herring gulls and Iceland gulls.
Today’s photo is of the Lake Norman bird. Say “good-bye” for now.
Taylor Piephoff is a naturalist with an interest in the birds and wildlife of the southern Piedmont: PiephoffT@aol.com.