Thayer's Gull (thayeri)

(last update: January 22, 2013)

Thayer's Gull - Plate 2a.

From: Identification and Variation of Winter Adult Thayer’s Gulls with Comments on Taxonomy, by Steve N.G. Howell & Martin T. Elliott, IN: Alula 4/2001.

Plate 2a. Wing-tip scoring criteria for P10.

Score 3: an isolated mirror separated from the pale basal inner web by a variably wide dark medial band and from the white tip by a narrow dark subterminal band.
Score 4: a variably complete white "tip" separated from pale basal inner web but contiguous with white tip.
Score 5: dark medial band incomplete; subterminal dark marks not considered in scoring.

© Martin T. Elliott.