25 August 2014

More Herrings and Ring-billeds: Late August

I spent some time studying the growing flocks of juveniles in East Chicago, Indiana yesterday. Same "boring" species but the immense variation in their plumage is far from boring!

Juvenile American Herring. East Chicago, IN. 24 August 2014.

A rather big-eyed look to this juvenile American Herring. East Chicago, IN. 24 August 2014.

Juvenile American Herring. East Chicago, Indiana. 24 August 204.
Interestingly, the three outer primaries appear rounded.
Juvenile Ring-billeds below - how can one not appreciate the incredible amount of variation in a cohort of similar aged birds, all presumably from the same colony?!

Juvenile Ring-billed. East Chicago, IN. 24 August 2014. Cinnamon tones throughout with rather dark tertials.

Below is a juvenile with a remarkably clean underwing. The axillaries and lesser/median underwing coverts are usually edged in brownish black at this age.

For comparison, consider the hatch year Ring-billed photographed moments before the bird above:

The secondary greater coverts on the underwing are typically pale on young Ring-billeds, as is seen in both examples.

Flight shots of juvenile RBGUs:

A presumed 2nd summer completing its second prebasic molt. Some individuals show no mirror and others a relatively large mirrors on p10. This one shows a tiny spot:

2nd cycles usually have "mostly" adult-like gray tertials, but there are individuals with rather "retarded" in black centers, like this bird: