OHIO-BIRDS Archives

May 2012

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From:
jay lehman <[log in to unmask]>
Reply To:
jay lehman <[log in to unmask]>
Date:
Mon, 28 May 2012 10:10:03 -0400
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Here are additional points on the ID which may seem to complicate the ID
but still seem to point to Great Black-backed in my opinion, still
recognizing the limitations of identification by only photos.

A close-up of the wing-tip at Haans' Flicker site shows an incursion of
black near but not at the tip of P10.

The black near the tip of P10 is one indication of fourth-year (or young
adult) rather than full adult GBBG according to Olson and Larsson. That may
be why this bird is hanging around Conneaut now. This Conneaut Gull appears
to not be a full adult bird.   From Olson & Larsson,

"Plumage development slow; takes at least four years to attain full adult
plumage, aften 1-2 years more, making precise aging outside first years and
full adult difficult."

Western Gull occasionally has a mirror on P9 in addition to P10. Also from
Olson & Larsson.  So, go figure.

The size ranges for Great Black-backed and Herring are:

61 - 78 cm (GBBG).     53 - 65 cm (American Herring Gull)

Thus, the smallest female GBBG is the same size (or nearly) as HERG.  I
have seen GBBG this small in the winter at gull sites along Lake Erie.

The white edges to the tongues on P6, P7 and P9 appear to be not the string
of pearls of Slaty-backed, just edges that some GBBG show,  See Haans
Flickr page and John Pojacnik's photos on RareBird.org.  Examples in Olson
& Larsson.

The apparent lightening of primaries and primary coverts on Haans Flicker
page appears to be the effect of light by comparison to John Pojacnik'
photos.

Interesting gull!

Jay Lehman, Cincinnati, sent from DROID

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