Monday, December 1, 2008

The Last Probable Bird

At the beginning of this year I compiled a list of all the birds I might see. As the year progressed, I broke that list down into categories: Probable, Possible, and Rarities (Yearly, 2-5 Year and 5 years +, referring to the general frequency that they show up in New York State). Each time I'd see a new bird I'd remove it from the list. Today, with just one month to go in my Big Year, I crossed off the last Probable Bird, the Thayer's Gull.

My search for this bird started in January, when I drove up to Niagara Falls in that first hectic month to join Willie D'Anna and Betsty Potter to go gulling. At that point there were several gulls I needed, and Niagara is the place to be for gulls. In the winter thousands upon thousands of gulls come to the falls and the Niagara river to flock and feed, and in those months Niagara probably sees more species of gull than anywhere else in North America. Iceland and Little Gulls are commonplace, as are Lesser Black Backed Gulls. Glaucous are less common but usual, and Black Headed Gull is not out of the question. Rarer gulls like California are seen annually, and birds like Ross's Gull, Ivory Gull and Slaty Backed Gull have all been seen here. Of course, these rarer birds are mixed in with monumental flocks of Herring and Bonapartes gulls.

That first trip was both exciting and rewarding...Willie is one of the great gull experts of New York, and is a great guy to boot. Betsy is keen-eyed and great at picking out that "odd" gull. Spending a day with them on the river is like reading three gull books, and more fun. We spent a lot of time on Thayer's that day, and although we had several "candidates", we never had a textbook bird. I should say that Thayers gull is a VERY difficult ID, to be attempted only by experienced and serious gull watchers. While I find I've been able to pick out Thayer's candidates on the river, I would never trust myself to make a definitive ID (and no one else would trust me, either!), so without Willie I'm not sure seeing the bird would be possible. I'd venture to say that this is the only bird like that for me in New York...everything else I can ID by call or fieldmarks or photos, albeit with multitudes of mistakes along the way and confirmation from more experience birders. That's the thing about gull ID, which is different from any other bird requires both good eyes and carefully trained thought. The bird must often be pieced together as in a detective novel before a final ID is reached. This is especially true of Thayers, a species with a checkered and sorid past. The Thayers was split from other gulls in the 70s through research that has been put into serious question...many believe that much of the study that defined the bird was simply fabricated. It is somewhere between an Iceland and Herring gull in shape and markings, and IDing one is like walking a razor...too far one way and it's an Iceland, too far the other and it's a Herring. A definitive bird is hard to come by, and so on that first trip I had to leave empty handed.

Back to this weekend, and it was time to try again. Right around now is a great time to look for large gulls at Niagara...they arrive earlier in November and by January the Thayers will start to leave. We had tried to go up last weekend, but snowy weather and poor visibility waylayed the trip. This weekend looked better, so after Thanksgiving we headed up to the Falls to try again. We birded above Adam Beck, a large power plant that feeds off of the Niagara, and the best spot on the river to look for Thayers. When you bird there you're actually on the Canadian side, looking back at the US...the birds there tend to glide back and forth over the border (to them the river) with frequency. The gulls are several hundred feet away and below, so you get the odd perspective of watching them from above. That allows for good study of their upper wing pattern, which is a clue towards finding a gull. When we first got there I was amazed by the number of birds...thousands of gulls milling around the river as far as you could see.

It's overwhelming to try and pick that Thayers needle out of a Herring haystack, but we got to work, and soon had several candidates. Unfortunately, these first birds were lacking in some way...legs not bubblegum pink, some black on the underwing, not enough black on the upperwing, not enough streaking in the head, a yellow eye instead of a black one, structurally not quite right. So we persisted, and persisted. The temperature was probably around freezing, but there was a cruel east wind that seemed to suck the heat right out of me, despite my three layers, parka, gaiter, and thermals. At one point I started shaking too hard to see through my binoculars. After warming up in the car for a bit and having a cold lunch, we continued. At about 1:30 we had been at Adam Beck for five and a half hours, and although we'd seen some good stuff (including a California Gull), we hadn't found our bird.

And then it of the other birders who had joined us picked up a candidate. He called it out as it passed the various landmarks around the power plant, and I finally got on it. Looks good, I said, and Willie agreed. I got out the camera and Willie guided me onto the bird. I started shooting, and the more we looked the better the bird got. Looking at the photos, we couldn't find any major flaws. That's as good a Thayers as we're going to see, said Willie, and I was happy to hear it. We headed back just as a cold rain began, and I was glad to have worked hard for this bird, to have spent hours for it and really shopped around, sharpened my eye and then saw what we were looking for, and I was glad to have had Willie and Betsy's company, both of whom, despite many years of birding, seemed as excited as I was to have found a classic Thayers.

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