Slaty-backed Gull (schistisagus) / オオセグロカモメ / 큰재갈매기

(last update: December 2015)

Kim Seog-min (South Korea)
Hideo Shimura (Japan)
Peter Adriaens (Belgium)
Mars Muusse (Netherlands)

Western Gull (occidentalis) 2406-14050 12CY, December 13 2015, Eureka waterfront, CA. Picture: E Fox.

Please visit Fox's Flickr photostream, for many more images.

Question "When is clean-headed really clean on the head?" That's what E Fox asked himself as well. He points it out: "At this point in my understanding of local species, a mature Western Gull with this degree of smudging on the head would be considered an Olympic Gull (WEGU x GWGU). Yet the number on the federal band of this marked bird reveals it was banded as a chick on the Farallons (in 2004!). If a presumably pure WEGU can be this streaked in the head, how is one to reliably identify hybrid birds? Or perhaps the question is, to what extent do Olympic Gulls breed south of Washington, if Glaucous-winged Gulls do not?".