01 March 2015

First Day of March: Glaucous & Great Black-backeds

I worked a few sections of the Calumet River in Chicago today (01 March 2015). 12 GBBGs and 5 Glaucous Gulls made up for the lack of Thayer's (1), Kumlien's (0) and LBBGs (0). I'm thinking some of our gulls must have moved on, likely to some of the dams and open rivers to the south.

Great Black-backed Gull (1st cycle).
Great Black-backed Gull (1st cycle). A rather dark bird holding on well to its juvenile neck, breast and flank feathers.
Two 1st cycle GBBGs and a 2nd cycle GBBG (back right). Did you notice the Glaucous Gull back there?
I ended up doing very little photographing and decided to spend a good chunk of time recording Herring calls (which are now becoming more and more vocal as the hours of daylight lengthen). In the process, I was pleased to get ~25 seconds of a 1st and 2nd cycle Glaucous both calling, in tandem, with a 1st cycle Great Black-backed. Glaucous Gulls - despite their bigger size - sound surprisingly similar to Herring Gulls. Great Black-backeds are in a class of their own.

Glaucous Gull (2nd cycle).
Glaucous Gull (1st cycle). Outer primaries worn and bleached (see below).

Inner primaries show brown markings that are consistent with the rest of the plumage.
The Outer primaries appear bleached and more worn.
This image is unquestionably underexposed  (to help capture the GLGUs). The snow also does a good job of tricking the camera's metering system which in turn makes the Herring Gull look extra dark - no it's not a Vega Gull :).
The 2nd cycle Glaucous on the right would not stop bullying everything around it - except for one large, presumably male, GBBG.
Herring Notes:

This 2nd cycle type is sporting a few adult-like rectrices. My guess is somewhere along the line, a few feathers were ripped out and then readily replaced. Tail and flight feathers are commonly tugged at during fights with congeners.

Herring Gull (2nd cycle type).
Next up is a 2nd cycle showing uniformly colored upperparts:

Herring Gull (2nd cycle).
Here it is in flight with a 1st cycle Great Black-backed:

If the inner primaries were any darker, you might start to suspect a LBBG.
Adult type Herring Gull. Shows little white mirror on p9 and small black spot on outer edge of p4.
I imagine this wingtip pattern is age-related and likely represents a young adult. 
Herring Gull (3rd cycle type).
Herring Gull (2nd cycle type). The contrasty upperparts make for a really neat-looking seabird...