Quiz kindly prepared by Calvin.
This photo was taken in January in coastal LA. Perched on a rock in the water, this is a cooperative bird that allows us to see several field marks. Good luck!
Answer will be displayed on March 1.
The size, shape, and overall plumage of this bird narrows it down to gulls and terns. Terns can be eliminated since the bill shape is short and stubby, as opposed to long and sharp. This leaves the gulls, which can be a particularly tricky group. However, the head pattern with the dark postocular mark behind the eye can rule out the large four-year (Herring, Glaucous-winged, Western, California, Heermann’s) and three-year gulls (Ring-billed, Short-billed). Our only remaining common gull is Bonaparte’s Gull.
Bonaparte’s Gull is a two year gull that has reddish pink feet, a dark postocular spot in the non-breeding season, a petite black bill, and silvery gray wings. Just to be safe, other rarer dark hooded gulls can also safely be ruled out. Little Gull has a smudgy dark cap in the nonbreeding season. Black-headed Gull has a reddish bill. Kittiwakes have a yellow bill. Franklin’s Gull has a dark cap, no postocular spot, and a white eye-ring. Laughing Gull has a longer bill. This only leaves Bonaparte’s Gull. This Bonaparte’s Gull was photographed along Ballona Creek in January 2022.
Congratulations to 2 Henrys, Lily, Ava, Merryl, and Thomas for answering Bonaparte’s Gull.