Tuesday, May 17, 2011

More gullage

Almost two months ago, when I had just started the migration watch on Sandy Hook, NJ, I wrote a little bit about the gull flock on the False Hook ("Gullage"), which at that point had grown to 1000+ individuals. Now, having just finished the count on Sandy Hook, I can look back on a pretty good gull flight this spring, which at the end gets the more interesting species. I missed out on Black-headed Gull this year, but where I'm from that is by far the most common gull, so no great loss for me. Did get Little Gull, lots of Bonaparte's Gulls, and throughout the count several individuals of both 'white-winged' species, Iceland and Glaucous. And of course there was that hybrid gull, Herring x Glaucous.

I want to share some images of an Iceland Gull I photographed last week, some Little Gull shots also, and some images of what I think is probably an aberrant American Herring Gull, but may be something more exciting?

Here's that first-cycle Iceland, in with Herrings and Great Black-backeds. Incidentally, what is the bird on the right? Is that just a bleached first cycle Herring Gull? Or something else? Shame I didn't get the entire bill on that bird, but I was going for the Iceland.

An open-wing shot reveals a tail band stronger than on most immature Kumlien's Icelands, but still within the wide range of variation.

Little Gull is rare but regular in northeastern New Jersey, and the bird found by Tom Boyle last week - I stood next to him when he called it out - stuck around for at least a few days. Saturday, it was joined by a second, more heavily marked individual.

The Little Gull below is less heavily marked, but still separable from the slightly larger Bonaparte's Gull next to it by its shorter legs, more pronounced carpal bar, dark tertials, and zig-zag pattern on the folded primaries.

Also on the False Hook Saturday was this oddball. What is this? At first, you might think Glaucous Gull: a fairly large white-headed gull with white wingtips. But the outer primaries have too much white in them.

The bill has unusual patterning, with a dark line along the edge of the maxilla and mandible.

Take a look at a few open-wing shots. This was the best I could do under poor lighting conditions, in the company of birders that I didn't want to deprive of great birding to be had on the False Hook right then (drake King Eider sitting on the beach, two Little Gulls around, immature Lesser Black-backed Gull, etc). Had I walked up to the bird, I probably would have scattered it and everything else that was there.

I think these open-wing shots show most clearly that this is not one of the more regular 'white-winged' gulls (Glaucous or Iceland).

Note the dark tail band, expected on a third cycle Herring Gull, not on a third cycle Glaucous.

Finally a shot of the bird next to a normal third cycle American Herring Gull. In this shot, there's a subtle yet appreciable difference in mantle color between the 'white-winged' and the normal Herring Gull. The mantle color may be good for Glaucous, but there's other disqualifying marks. So… what is this bird? I don't have access to the Howell & Dunn gull book, so I can't delve any deeper than my admittedly limited knowledge of large white-headed gulls permits. If anyone wants to shine their light on this one, comments always welcome!

On a different note, I want to thank all you Jersey / NYC metro area birders who came to the platform this spring and made my time there more enjoyable. I had a great time, and you made it worth it.


Tom Boyle said...

Maybe just an aberrant Herring Gull. The head is rounded like a Herring Gull.I saw this bird also.
I don't think the bird is a hybrid. I once had a Common Yellowthroat with a white mask. Odd plumages happen. Enjoyed your company this spring John...

Tom Boyle

johnvandort said...

Tom, I think you're right. Thanks for commenting. I too enjoyed birding with you on the Hook this spring.