A Black-tailed Gull (Larus crassirostris) has been hanging out on a log boom in Tacoma, WA, for the past couple of weeks. Tacoma is normally far outside my “chase radius” for a single bird, but Marsha was working a conference in Seattle last Saturday, so it was only a half-hour drive from there to the bird. Since this is probably the only chance I will have to see this Asian species, I was happy to spend the four and a half hours standing on the shoreline waiting for this bird to appear.
The Black-tailed Gull finally arrived around 2:30 and provided extended views of the field marks that make this species so distinctive. This photo and the ones that follow were taken through my scope. While the camera and scope are obviously not compatible for digiscoping, these photos show that you can obtain documentation of rarities without a lot of special equipment. The key field marks for this species include: yellow drooping bill with bright red tip and black subterminal band, solid black tail with white terminal band, pale irises, white crescents above and below the eyes, and dusky markings on the nape that wrap around the head (winter).