For the third season in a row, I have been attempting to document the number of individuals of the more uncommon gulls in the Duluth-Superior harbor during the fall and winter of 2010-2011. This is done by analyzing photos, most of which I have posted to www.pbase.com/karlbardon under Duluth-Superior gulls fall/winter 2010-2011.
Every year this project seems to get more time-consuming- this year it has taken me until late January to sort through all the photos... I have been even more thorough this year, with the main galleries documenting virtually all individuals. Any comments are welcome (including additional dates for individual birds documented here). The total numbers documented include the following: 68 Thayer's Gulls, including 33 first-cycles, 10 second-cycles, 7 third-cycles, and 18 adults (compared to 49 total individuals last year and about 25 the year before). This increase is probably mostly due to a much more concerted effort on my part to identify every individual first-cycle bird, which I had not done in the past. 10 Iceland Gulls, including 1 first-cycle, 2 second-cycles, 2 third-cycles, and 5 adults (compared to 12 total last year and 5 the year before). Perhaps even more than ever, many individual Iceland-Thayer's Gulls appeared to be intermediate and identifications seemed arbitrary. My continued study of adult primary patterns suggests that as many as half of all Iceland-Thayer's Gulls in Duluth-Supeiror are actually hybirds (or intergrades, since these are undoubtedly the same species). 20 Glaucous Gulls, including 14 first-cycles, 1 second-cycle, 4 third-cycles, and 5 adults (adult count based on most seen at one time). Although the overall number seemed less than previous seasons, this is the first season I have attempted to identify every individual non-adult Glaucous Gull. 14 Great Black-backed Gulls, including 11 first-cycles, 2 second-cycles, and 1 adult (compared to 15 total last year and 5 the previous season). 4 Lesser Black-backed Gulls, including 2 first-cycles and 2 adults (compared to 2 first-cycles and 1 adult last season) 1 Slaty-backed Gull, adult present from 19 December 2010-16 January 2011, following a third-cycle last year which may or may not be the same individual. 2 California Gulls, both of which were adults, following a first-cycle bird last season 1 Nelson’s Gull. an adult seen 29 November-2 December 2010, appearing to be the same individual seen last year on 1-3 January 2010. Karl Bardon Duluth, MN ---- Join or Leave mou-net: http://lists.umn.edu/cgi-bin/wa?SUBED1=mou-net Archives: http://lists.umn.edu/archives/mou-net.html
