25 September 2011

Lake Carlyle Sabine's Trip 2011

Every fall, tens of juvenile Sabine's Gulls are found on large lakes and rivers throughout the United States as they make their transequatorial journey to the southern hemisphere. Mid-September through mid-October is peak time to find a Sabine's in the interior and Illinois is no different. Illinois and Missouri birders know that their best chances to see this sternine gull is to attend an "inland pelagic" field trip to Lake Carlyle in Clinton County Illinois (to read about last year's trip, click here).

Still, finding a SAGU at Carlyle could be tricky. For instance, earlier this month on 14 September 2011, Dan Kassebaum had a record high of 9 SAGUs while conducting an evening lakewatch. Three days later, a St. Louis Audubon contingent found zero, but then several were found just a few hours after SLA birders departed the lake. On Friday, 23 September 2011, three Sabine's were present, including an adult which is very exceptional! The next morning, birders attending the IOS annual pelagic could only turn up one (found by yours truly). Numbers seemed to fluctuate all week and it gave me the impression of a very touch-and-go presence. I'm sure that with a little data recording of weather systems and weather conditions one could narrow down the reason(s) for these radical turnovers. Is it the size of the lake that makes these birds go unnoticed? Do they spend their days feeding at other nearby locations and then return for an evening feeding frenzy? Or, are they truly migrating out and being replaced by new arrivals?

Unlike last year's Sabine's, this year's bird was first found sitting on the water. This is obviously a bigger challenge than finding one in flight. In flight, Sabine's has such a bold and unique pattern to its upperparts that it's really difficult to mistake:

Juvenile Sabine's. Lake Carlyle, IL; 25 Sept 2010, by Amar Ayyash.

Birds sitting on the water, which again are usually juveniles with brownish-gray tones, blend in quite nicely:

Oh, okay...there it is.
One tip that I could offer birders who are searching for this species is to stop looking for a large white gull - even Ring-billed sized is too large! Sabine's is about the same size as a Bonaparte's Gull. Scan the water's surface and watch for any dark, protruding irregularities. Sabine's bobs its head frequently when feeding on the water's surface and a diligent observer should be able to pick up on this movement.

Oh, yeah...that's much better!
We approached this bird for better looks like any smart birder would and we weren't disappointed. Birders on our boat, led by Captain Bob Fisher, observed this feeding behavior which recalls a lazy phalarope picking food from the water's surface. Everyone enjoyed good views and off it went, passing boat #2 and then boat #1:

Juvenile Sabine's. 24 Sept 2011, by Amar Ayyash
Other gulls found on the lake include this hatch-year Franklin's:

 And three Lesser Black-backed Gulls, including this 3rd cycle:

The night before our trip, birders observed 2 Laughing Gulls while conducting a lakewatch and one more the morning of, making it a 7 gull weekend for this site. The fact that no Laughing Gull or adult Sabine's were found during the boat ride or throughout our afternoon birding adds to the mystery of the movements of these gulls.