glaucoides - kumlieni

(last update: January 26, 2012)

possible Kumlien's Gull (kumlieni) x Thayer's Gull (thayeri) adult, February 12 2007, St John's, Newfoundland, Canada. Pictures: Chris Gibbins.

Age adult winter, lacking brown wash on primary coverts. Large bird, and in wingtip pattern beyond the Kumlien's score Table (in this bird there is a full medial band on P10, reaching all the way to the inner edge of the feather). Bird with quite a long, thick bill and sloping forehead, generally more thayeri in structure. However, grey mantle matches nicely to Kumlien's Gull, and iris is particularly pale.

Wingtip darkness score: 3 - blackish grey (Estimated Kodak 14-17). In the study by Howell & Mactavish, about 5% of Kumlien's Gulls in New Foundland belong to this category, see Table 1.

Wingtip scoring for dark markings on P5-P10: 3-5-5-5-5-5. See Plate 1 for explanation.

Wingtip pattern category: beyond Type Q, Stage 6; darker grey or more extensive grey marks on the outer six primaries with complete subterminal bands on three to four primaries among P6-P9. See primary patterns for explanation. In this bird, also P10 has a complete sub-terminal band, which is even beyond what's illustrated for 'classic thayeri' (Type 3, in primary patterns).

Iris colour variation: 2 - pale greenish or yellowish, moderately marked with brown. In the study by Howell & Mactavish, about 18% of Kumlien's Gulls in New Foundland belong to this category, see Table 3.