[EBB Sightings] Summer Camp birds: Birding Tech / Mystery Gull

EBB folks:  I am forwarding this message at the request of Brian Fitch.  
If you have questions or comments, please address them directly to Brian 
at:  fogeggs at aol.com    Thanks, Kay Loughman, Berkeley.

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Last week in camp, we found nothing too unusual that others haven't 
already reported, with the exception of the odd gull that led me into a 
mistaken ID on the Northern Cal Birdbox.  I find it rather ironic that 
my first call to the birdbox on my new cell phone would also be my first 
error since I began using the line in '96.

The gull was a heavily marked juvenile that even the children were able 
to pick out of the flock.  It was smaller than nearby California Gulls, 
did not associate with any other species, and was actually attacked 
twice by an adult Western Gull.  The gull's chest, flanks and undertail 
were barred, the head had dark streaking that at first looked like a 
cap, the beak was straight and all dark, and the underwing when briefly 
raised appeared to show a white flash, all of which led me to jump into 
thinking it was a young jaeger.  On returning later sans kids and giving 
it more study, I quickly recognized that the wings and mantle were 
wrong, as the coverts were all very dark in the interior with very wide 
whitish margins, giving a checkered appearance.  The primaries were not 
fully developed, being only as long as the very fluffed up tertials, and 
the wingtip was not very dark.

I wasn't able to go home right away, but was able to check the internet 
for juv jaeger photos, and then quickly retracted my phone call.  I've 
been studying gull references in my spare time this  weekend, and have 
not found any drawing or photos that really match the bird, with the 
exception of photos and drawings of juvenile "Baltic Gull", the 
subspecies of Lesser Black-backed Gull found through central and eastern 
Europe.  I'm by no means claiming that the Marina bird was this species, 
as the wingtips were not a good match, though most everything else was.  
I definitely learned that fresh juvie gulls are something I need a lot 
more experience with, as I usually only see very few species straight 
out of the nest.

On a positive note, the Pelagic Cormorant nest at the Marina had three 
chicks in it on Thursday morning, and the Olive-sided Flycatcher on 
Vollmer Peak in Tilden continues to aggressively hold territory as if it 
too were breeding.  We'll keep watching for fledglings at both sites.

Brian Fitch & crew