the hybrid gulls, Re: [Tweeters] Recent Pelagic Highlights....

Ryan Merrill rjm284 at gmail.com
Thu Mar 14 23:23:35 PDT 2013


No problem, Richard. As I'm sure just about everyone can agree on,
gull identification can be quite difficult and often somewhat
subjective, more so I would say than most other identification
challenges we face here in the Pacific Northwest. It's only been the
last few years after spending countless hours sorting through our mess
of gulls that I've felt somewhat comfortable identifying
Glaucous-winged x Herring hybrids.

Glaucous-winged x Herring Gull
http://www.flickr.com/photos/rjm284/8555362752/

This is an adult gull. The plumage is like a Herring Gull, with a
pale gray mantle and sharply contrasting black primaries. Not
particularly visible with the harsh lighting of this photo is that the
undersides of the primaries were grayish rather than black. On the
other hand the overall shape of the bird is more like that of a
Glaucous-winged Gull, with a more pronounced belly and hefty look to
the neck and head. Interestingly, during the whole cruise we could
usually tell whether an oncoming gull was going to be a Herring or
Glaucous-winged/Western before seeing any plumage characteristics
simply by how large the body was in proportion to the whole bird, with
Herrings have a sleeker look to them at that angle. The bill is also
quite thick compared to a Herring Gull, and has a pronounced gonydeal
angle. The eye color is darkish unlike a Herring Gull. The brownish
patterning on the neck looks like the pattern of a Herring, with it
being separated into rows unlike Glaucous-wingeds that are very
smudgy.

Glaucous-winged x Glaucous Gull
www.flickr.com/photos/rjm284/8549326117/

This is a large pale gull that if it weren't for the bill you could
almost call a Glaucous Gull. Unlike a Glaucous Gull though, the basal
two-thirds of the bill is mostly dark but does have some pinkish
smudging. The shape of the bill is also Glaucous-like, being parallel
sided and lacking a gonydeal angle as large as a Glaucous-winged Gull.
Also, first-cycle Glaucous Gull is generally more crisply patterned
on the mantle and upper-wing coverts.

Hope that's useful to people and I'd be happy to talk gulls more with
anyone who's interested.

Good birding,
Ryan Merrill
Kirkland, WA




On Thu, Mar 14, 2013 at 12:36 PM, <Pterodroma at aol.com> wrote:

> Subject was: [Tweeters] Recent Pelagic Highlights - Short-tailed Albatross,

> Parakeet Auklets

>

>>Some photos from the cruise can be found here:

> http://www.flickr.com/photos/rjm284/sets/72157632984638583/

> Ryan -- Nice photos as usual, albeit from a foreshortened "sequestered"

> cruise. Sorry about that but that's probably our future and reality for

> awhile.

>

> Of particular interest, to me anyway, were the two hybrid gull photos.

>

> (1) Glaucous-winged x Glaucous Gull

>

> (2) Glaucous-winged x Herring Gull

>

> For those of us larid-challenged around here in tweetersland, and there ARE

> millions, would you mind elaborating to some degree, maybe point by point,

> why those gulls were identified as such. I am not challenging or

> questioning the identifications, rather I think this might be a useful time

> for some class action edification for all. Coming from you, it should be

> pretty good, and we all could stand to learn a few things we might not have

> known before. Thanks.

>

> Richard Rowlett

> Bellevue (Eastgate), WA




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