Anywho, the IOS trip to Carlyle finds birders traversing the lake for several hours using a flotilla of 2-3 pontoon boats. Bread and popcorn is used to chum the gulls and eventually a Sabine's is discovered by one party which then alerts the other boats.
This year, I had the pleasure of attending this field trip for a 2nd time and I was not dissapointed in the results. In fact, I've attended this trip the last 2 out of 3 years with Sabine's gone unrecorded on the trip I missed. Are you thinking what I'm thinking? Yes, I should attend this trip every year so that other birders get a chance to see this species :) Tim Kussel for instance, has had a 4 out of 8 success rate and so it's not gravy every time you get on those boats.
Our search for Sabine's Gull took less than 30 minutes when one of our crew members, Anthony Friend, spotted a Sabine's flying right towards us. As expected, the bird was a juvenile that was probably no more than 3 months old. I should mention that in Brock's data from 1998, out of 111 aged birds, only 13 were adults. These numbers should have significant meaning to the vigilant birder (not I).
|Juvenile Sabine's Gull by Amar Ayyash, Carlyle Lake IL, 25 SEP 2010|
|Same individual as above.|
Last month, I was reflecting on the uniuqeness of Sabine's Gull's molt strategy but I failed to put two and two together when watching this species from the Olympic Pavillion. For a brief moment, I thought I may have had an adult Sabine's out on the lake. I kept this thought to myself and studied the bird a bit more. Lighting conditions were less than ideal and from afar the brownish/gray mantle seemed solid gray as expected in an adult. There is no parallel as in the adult/juvenile Black-legged Kittiwake or adult/juvenile Bonaparte's when it comes to the upperpart pattern of Sabine's; Both ages are virtually identical from above.
The smoky wash to the nape and breast was undetectable to my inexperienced eyes. Since the bird I was watching did not have a black hood I thought, "Oh, why can't that be a basic adult"? Although knowing what to expect from earlier in the day during the boat trip, I squinted and squinted until I made out the thin tailband. The tailband was very hard to make out and I think that if lighting conditions were any worse, and had I not had a biased expectation from a few hours prior, I may have missed it completely.
Fortunately, a most humble birder from St. Louis rightfully reminded birders of Sabine's molt strategy in a recent thread on the Illinois Birders' Forum (IBF). Unlike other gulls that breed in the northern hemisphere, Sabine's is a high-Arctic breeder with a taxing migration. It does not have the time and energy to manage a complete prebasic molt on the breeding grounds or en route while migrating. Rather, this molt is delayed, or "suspended", until it arrives at its wintering grounds. Although limited head and body feathers may be molted during migration, an adult Sabine's seen in the interior states in fall will almost always have a full hood effect. In fact, Olsen estimates that over 90% of Sabine's Gulls seen in the northern hemisphere will have full summer hoods from August through early October. This implies that one should expect to see one of two plumages in Illinois: First Basic or Definitive Alternate, with the latter being much less common.
A juvenile in flight: http://www.youtube.com/watch?v=aj_jK9LNQ1Y&feature=related