Date: 3/11/17 5:45 am From: Shaibal Mitra <Shaibal.Mitra...> Subject: RE: [nysbirds-l] Black-headed - Ring-billed Gull hybrid at Goat Island
Hi Willie and all,
Wow--what a neat-looking bird!
I can see the logic behind the identification: the combination of dark hood, white wing wedge, absence of white tips to the inner primaries and secondaries, and reddish bill and legs suggesting Black-headed Gull; and size, structure, extra dark in the outer primaries, and white apical spots on the outer primaries suggesting Ring-billed Gull.
But to me, this bird looks so unlike a Black-headed Gull that I remain puzzled. Specifically, it looks large, thick-necked, large-headed, broad-winged, and heavy-billed. Black-headed Gull is only half the mass of a Ring-billed Gull and very differently shaped, whereas this bird looks quite similar to Ring-billed Gull in overall size and structure. It is of course possible for hybrids to tilt toward one parent or the other in various ways, as opposed to showing intermediacy, but note that the Sullivan County bird from 2002 showed much more intermediacy in these very features (e.g., more obvious influence of Black-headed Gull in terms of size and shape). Looking more closely at the plumage, I also note that the hood seems to lack any of the brownish tones usually evident in Black-headed Gull, and that the mantle appears subtly darker than those of Ring-billed Gulls (Black-headed Gull is notably pale-mantled).
Although I'm not able to propose a better hypothesis at this point, I thought I would contribute these impressions.
From: <bounce-121321009-11143133...> [<bounce-121321009-11143133...>] on behalf of Willie D'Anna [<dannapotter...>]
Sent: Friday, March 10, 2017 5:43 PM
To: 'Geneseebirds'; <geneseebirds-l...>; 'David Suggs'; 'nysbirds-l'
Subject: [nysbirds-l] Black-headed - Ring-billed Gull hybrid at Goat Island
For the second straight day, a very rare BLACK-HEADED GULL – RING-BILLED GULL hybrid was seen at Goat Island on the Niagara River. The bird was found yesterday by Derek Lovitch from Maine and another birder but tentatively identified as a Laughing Gull – Ring-billed Gull hybrid. Both of these hybrid forms have been recorded before. Derek told Chris Kundl about the bird and Chris was able to obtain photographs yesterday and today. It was Chris who initially and correctly, I believe, identified the bird as a Black-headed X Ring-billed.
Although most birders will not chase a hybrid, you are unlikely to see this form ever again, as it is extremely rare. Yesterday, the bird was in the parking lot on the upriver (east) end of the island. This is the end away from the falls. Today, it was in the shallows just off of Goat Island, on the rock shelf above Three Sisters islands – the usual place where the gulls roost. It was very close to shore today and although Chris was able to show me the bird today, I was not prepared to photograph it, as this was just an impromptu stop. The bird is in alternate plumage with a hood that is not solidly black. The bill is orangy-red with a black band. The legs are dull orange. The primaries and primary coverts show a weak representation of the typical white wedge on the upperwing that is seen on Bonaparte’s and Black-headed Gulls. However, there were also some black marks in the white. The undersides of the primaries are not dusky, as on a Black-headed Gull. The folded wingtips look similar to those of the Ring-billed Gulls – black with white apical spots on each primary. The structure of this bird seems closer to a Ring-billed Gull than a Black-headed Gull to me, though slightly smaller and smaller-billed. Note that this bird frequently buried itself among the many Ring-billed Gulls here and could be very hard to pick out, despite it’s obvious hood. It was the only hooded gull at Goat Island.