northern argentatus - wingtip pattern
Posted: Fri Dec 23, 2011 10:49 am
This month we saw incredible flocks of Herring Gulls from Scandinavia at the beaches, with groups of several 1,000's together in compact groups at small areas. After some stormy days, large colonies of American jack knife clam (Ensis americanus) became available as food resources and this early Xmas feast was well appreciated.
http://www.gull-research.org/hg/HG5CY01.htm repeats the table on 200 wingtip patterns from various Norwegian locations that was published by Barth in 1968. Many birds from far northern origin have only limited black in the wingtip. Interestingly, birds with black on only 5 primaries, may still show a very limited mirror on P9 and a full sub-terminal band on P10. But most eye-catching birds are those with thayeri patterns on P9 and P10, simply beauties!
http://www.gull-research.org/hg/HG5CY01.htm repeats the table on 200 wingtip patterns from various Norwegian locations that was published by Barth in 1968. Many birds from far northern origin have only limited black in the wingtip. Interestingly, birds with black on only 5 primaries, may still show a very limited mirror on P9 and a full sub-terminal band on P10. But most eye-catching birds are those with thayeri patterns on P9 and P10, simply beauties!