05 November 2011

FOS Thayer's Gull at Calumet Park

I officially kicked off the start of my white-winged gull season today with a 1st cycle Thayer's. I got off to a late start after having slept in with consequence. I had an important appointment at 2:30 a.m. but overslept. This almost never happens to me. In fact, it has never happened to me! Oh well - life must go on.

I got to Chicago's southernmost lakefront park, Calumet Park, a little before noon and walked out to the fishing pier. Much to my delight, the gulls came in with haste today. When not on one of the two beaches, the larger gulls usually come in from the breakwall out on the lake in Indiana waters, or south of the park, from Hammond:

1st cycle Thayer's Gull (left) with adult Ring-billed Gull (right). Calumet Park, Chicago IL; 5 NOV 2011

The bills on these young Thayer's always seems big to me, suggesting American Herring Gull, but the silvery underprimaries and venetian-blind effect to the upperprimaries are unmistakable. Overall, Thayer's is a neater looking bird than Herring. The upperparts are more neatly patterned and the underparts have a velvety look to them.

The dark outer webs and paler inner webs to the primaries eliminate American Herring.
 Note the juvenile scapulars with pale edges. This species has a somewhat frosty look compared to Herring.  
Surprisingly, 6 Bonaparte's Gulls (5 adults, 1 2nd cycle) came into the bay and allowed great looks! This is somewhat unusual on the lakefront and exceptional for Calumet Park. When I do see Bonaparte's here, they're usually far out over the lake as flybys (Indiana waters). It's unfortunate that Lake Michigan doesn't get greater numbers of this species like Lake Erie and Lake Ontario.

The presence of this species is almost a requisite for finding some of the rare, small gulls. Bonaparte's do not winter on Lake Michigan.

Adult Bonaparte's Gull. Calumet Park, Chicago IL; 5 NOV 2011.

This contingent of BOGUs seemed perfectly comfortable around the larger gulls. In fact, they seemed to prefer the company of the American Herrings over Ring-billeds:

Who says BOGUs don't take bread?!