Posted by Brennan Mulrooney on September 24, 2002 at 17:38:50:
Gerard Phillips, Mark Heddon, and myself spent a couple of hours on the 23rd looking at the dark mantled gull in Key West. It certainly "looks" like a Slaty-backed (based on comparison with photos from Alaska and Japan). If it's a hybrid I don't know how we'll ever know, short of DNA analysis.
I was a bit shocked that there weren't any other birders down there looking at the bird. It looks quite comfortable there on the beach, I would guess it'll be there for a while...but who knows? As the photos show, it's not exactly shy. I highly encourage everybody to get down there and look at this bird. I know Key West is a bit out of the way, but it's closer than Alaska!
Brennan