Iceland Gull in St. Louis County
2012-12-08

'Rare Regular' in Minnesota

This adult Iceland Gull was seen at Canal Park on 8 December 2012 among over 1,110 Herring Gulls, plus one other adult Iceland Gull, 11 Thayer's Gulls (3 first-cycle, 3 second-cycle, 2 third-cycle, and 3 adults), 4 Great Black-backed Gulls (1 first-cycle, 1 second-cycle, 1 third-cycle, 1 adult), 4 Glaucous Gulls (2 first-cycle, 2 second-cycle), and 1 Ring-billed Gull. So why is this Iceland Gull so special? I believe this is the same adult Iceland Gull which has returned to Duluth to overwinter for the past four years, based on the precise pattern of dark markings in the outer primaries. Note the tiny gray subterminal mark on primary number 5 (counting from the innermost outward). Although Kumlien's Iceland typically has dark subterminal marks on only 5 outer primaries while Thayer's shows 6, there is a small amount of overlap in this feature (perhaps due to an unknown amount of introgression or hybridization). On this Iceland, note that the white subterminal tongue on P9 extends across the outer vane of the feather to join the terminal white tongue on P10.

Karl J. Bardon