Saturday, March 29, 2014

Slaty-backed Gull!!!

Kip found a Slaty-backed Gull at the 3 Oaks Ponds this morning.  These ponds are usually good for about one really good bird most years (last year Pacific Loon, previously Arctic Tern).  I guess this means we don't have to check them any more this year.

The bird was just resting amongst the Herring and Ring-billeds.

 I was shooting through a fence, I put in a couple similar pics here, I'm not sure they're all that different though I tried a few different settings on the camera.

Note the size is about the same as the HERG, it's more pot-bellied though.  It's got a really wide white tertial skirt which is typical of SBGU (per the books, unlike Kip, I'd never seen one).  The legs are solidly pink.  The eye is pale with a little dark smudging around it giving it the fierce look.  The mantle color looked just slightly darker than what a LBBG would have.

And the money shot...
 At one point it did some preening, and after that leaned forward and stretched.  You can bet the shutter was banging away.  It's got the sub-terminal white spot on P8 and P7 that creates the "string of pearls."  It didn't quite spread the primaries fully all the way open, I bet even more white would be visible with a well timed flight shot.

After that it went back to sleep.  You can get a hint of some of the other vestiges of winter dark head markings, though again it's pretty distant.

Hybrids always have to be considered with gulls.  I don't have gull references available just now so I'm not going to go into them in great detail, but the mantle color, eye color, head markings, tertial skirt, leg color, and wing pattern all seem very average for Slaty-backed.  Various dark-mantled hybrids including GBBGxHERG, GBBGxGLGU, and whatever Gull-nasty is have been featured on various posts here, just click on the "dark-mantled hybrid" tag on the right hand column under labels.

1 comment:

Cathy Carroll said...

Nice write-up, nice photos. Great bird.