Ben, it is my sense that Herring x GW hybrids are more likely than Pure GW Gull in Colorado. This bird seems to have a lot of GWGU in it (for example, the white secondary skirt due to long secondary feathers), the for a pure GWGU in its second winter, I would expect paler primaries and a mostly dark bill. A retarded 3rd winter is another possibility. But, I think the best solution to this puzzle is 2nd winter hybrid (aka Cook Inlet Gull).
Interesting bird. Nick Komar Fort Collins CO > On Jan 10, 2019, at 4:59 PM, Ben S <benr...@gmail.com> wrote: > > Hi all - > > I saw this bird back on the evening of Tuesday, the 8th, sorry for the late > notice. At the time I had assumed it was an immature Herring or Thayer's > Gull. I am not good at IDing immature gulls, so I uploaded some pictures to a > Whatbird ID forum. To my suprise, a moderator responded that it could well be > a Glaucous-winged 2nd winter. This bird was on the ice with Ring-billed, > Herring, and a Thayer's Gull. Female Black Scoter was also present. Since it > is a rarity in Colorado, I was just hoping for a confirmation or rejection on > the Glaucous-winged ID before I enter it as such into ebird. Here are a > couple photos: > > > > <IMG_7604 - Edited (3).jpg> > > > > <IMG_7605 - Edited (5).jpg> > > > Also, here's a link to my ebird list, with more pictures of the possible > Glaucous-winged Gull, as well as some pretty good pics of the Black Scoter: > https://ebird.org/view/checklist/S51485423 > > > Ben Sampson > Centennial, CO > > -- > You received this message because you are subscribed to the Google Groups > "Colorado Birds" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to cobirds+unsubscr...@googlegroups.com. > To post to this group, send email to cobirds@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/cobirds/9bf1f395-f303-46ac-a61b-a56772ef8e69%40googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > <IMG_7604 - Edited (3).jpg> > <IMG_7605 - Edited (5).jpg> -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To unsubscribe from this group and stop receiving emails from it, send an email to cobirds+unsubscr...@googlegroups.com. To post to this group, send email to cobirds@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/21835B22-E326-4682-8A2C-F068DE9D5860%40comcast.net. For more options, visit https://groups.google.com/d/optout.