Iceland Gull in St. Louis County
2013-09-20

'Rare Regular' in Minnesota

Juvenile Thayer's Gull (Larus thayeri) observed on both sides of the Minnesota / Wisconsin state line at the Superior Entry, 20 September 2013. This represents the third earliest date for thayeri of any age in Minnesota, following records of single adults 15 September 2007 (Crow Wing County, A. Schirmacher, no details) and 18 September 2004 (Lake Calhoun, Hennepin County, †P. Budde). The most remarkable aspect of this record is the bird's age. With very few exceptions, adults arrive first in early October (rarely, late September) and the first juveniles arrive 10-14 days later. A cursory review of fall records back to 1973 (when this species was split from Herring Gull) found only one September record of a juvenile (9/28 Park Point, Duluth, †K. Eckert). A compendium of early and late dates for Wisconsin at the WSO website lists only two September records earlier than the 20th: 4 September 2001 (Sheboygan County, D. Tessen), 9 September 1980 (Douglas County, J. Polk), and 14 September 2003 (Sheboygen County, S. Baughman). The above image shows its all black, relatively petite bill; uniform tan plumage with the outer webs of the outermost 4 or 5 primaries and secondaries shaded slightly darker brown; and inner primaries paler tan, producing thayeri's classic "dark-light-dark" pattern across the remiges. On the ventral surface of the right wing, slightly darker brown tips of the outermost 4 or 5 primaries can be discerned. The bird also had a tan tail band. This taxon nests on cliff colonies of the Northwest Territories and Nunavut in the Canadian Arctic. Our delayed 2013 spring migration and late ice out make this early juvenile even more amazing, though conditions in the Western Great Lakes were undoubtedly different than conditions in the Canadian Arctic.

Peder H. Svingen