Well, I know it’s summer, and many of you have other (better?) things to do than read a blog largely about dead birds. But the rare “Live Bird Quiz” I posted on Tuesday brought some long-time SEANET devotees out of hibernation. John Stanton, Helen Rasmussen and Libby Rock correctly identified the flock of loafing gulls as Bonaparte’s gulls in non-breeding plumage. Libby wrote, “Ooooh, so sweet! Bonaparte’s Gulls, in winter colors? One of my faves – and what else has that lovely spot on their heads?” That question got me thinking, what else DOES have that lovely spot on its head? Well, let’s see…the candidates would be Little Gulls and Black-headed Gulls. The aptly named Little Gull is the Smallest Gull in the World. They are primarily a Eurasian species, but a few pairs were discovered nesting in North America in the 1960s. They are now by no means a common sighting, but show up consistently from year to year in winter along the East Coast.
Complicating, or maybe assisting, attempts to tell them apart from Bonaparte’s Gulls, the two species will flock together, so seeing a Little Gull in among the Bonaparte’s is not out of the question. When seen side by side, the Little Gull will appear noticeably smaller than a Bonaparte’s and have more of a black cap, in addition to the black “ear spot” they share with Bonaparte’s. In flight, non-breeding adult Little Gulls are distinctive for their dark underwings (Bonaparte’s, like most gulls, show a pale underwing with black wingtips.)
The other possibility, the Black-headed Gull, shares the same sort of background with the Little Gull: another European native, records of the species in North America increased throughout the last century, and the first record of North American breeding by the species came in 1977. Accounts differ on what sort of company they keep; Sibley says they “often consort with Laughing and Ring-billed Gulls,” while Cornell’s Lab of Ornithology reports that they frequently flock with Bonaparte’s Gull. I suspect both are true. So, how to tell a Black-headed from a Bonaparte’s? Non-breeding adults of the two species are quite similar, but the Black-headed will show dark red legs, and a heavier, red bill, as compared with the pink legs and black bill of the Bonaparte’s.