glaucoides - kumlieni
(last update: January 26, 2012)
Table 2: Wingtip pattern variation of adult Kumlien’s Gulls in Newfoundland (N = 345 birds).
From: Identification and Variation of Winter Adult Kumlien’s Gulls, by Steve N.G. Howell & Bruce Mactavish, IN: Alula 1/2003.
See also chart for explanantion of stages and classification criteria.
Primary pattern variation can be envisioned by starting with an unmarked wingtip (Stage 0; Plate 2, a) and building upon this (Plate 2).
The commonest pattern (and that of the type specimen of Kumlien’s Gull) was Stage 4 (55%): darker grey or more extensive grey markings on the outer five primaries (P6-P10) with complete subterminal bands on zero to three feathers among P6-P9 (most commonly on two to three primaries; Plate 2, j-m). This was also the pattern considered typical of Kumlien’s Gull by Grant (1986). Only 4% of Stage 4 birds had no complete subterminal bands, 12% had complete subterminal bands on only one primary (95% on P8; Photo 15), 44% (and the type specimen) had complete subterminal bands on two feathers (88% on P7-P8) and 39% had complete subterminal bands on three feathers (97% on P7-P9).
More extensively patterned wingtips were uncommon.
Of 345 birds, only 14 (4%) had no visible darkening on the outer webs of the outer primaries (Stage 0 = "white-winged"), although seeing darker markings in the field can be virtually impossible (see Bird H, Bird I, Bird J, Bird K, Bird L). The overall appearance (structure, dorsal tone, etc.) of such birds may be typical of other Kumlien’s Gulls, as in this Newfoundland research. Six of these 14 had unmarked pale eyes like Iceland Gull (score of 3); one had an eye score of 1.5 and seven had an eye score of 2.5. If the pale-eyed and white-winged birds were Iceland Gulls they made up only 1-2% of the Newfoundland wintering population.