I do not have any experience with Little Gulls. However, I was wondering if anyone could answer me the following question. By going on this picture alone, what field marks would eliminate the possibility of this bird being a Bonaparte's Gull, transitioning into its basic plumage?
Hi Chris,That's a great question. I'm on the road right now in Northern Ontario, but when I get a chance, I'll post another of Rick's photos which provides a side-angle (or perhaps James can?). I have zero experience with Little Gulls in the field, and obviously the first-fall birds are the trickiest, but this bird appears to exhibit several features that lean toward Little Gull including: Smallish-looking head/beak, somewhat of a capped appearance with more than average dark markings on the head/neck than typical Bonies, and the carpal bar appears fairly dark and robust (better viewed from the side). Alone, none of these features exactly "lock" in the ID, but together I think they're fairly good... but what do I know?
Hi Chris,Apologies for not posting the other photo earlier, which is up now. I can only echo what Russ is saying about this bird that, on balance, of the plumage characteristics to look at (some of which show overlap with Bonaparte's), all point towards Little Gull. Overall, the amount of remaining dark juvenile feathers, especially in the collar and crown are good for Little. Structurally, the golf ball sized head, steeper forehead (Bonaparte's, like Black-headed have a more sloping forehead) and small looking bill also point to Little. And, the bird has a dainty look to it overall, which is convincing for Little Gull. It would of course be good to hear the opinions of folks with more recent experience with the species.
Russ and James, thanks for the comments, and thanks James for putting up the other photo. No need to apologize James. Second photo definitely helps. Learned a few things as well which is always great.