Thayer's Gull (thayeri)

(last update: January 22, 2013)

Amar Ayyash (USA)
Mars Muusse (Netherlands)

Thayer's Gull sub-adult, October 12 2014, Anchorage, AK. Picture: Peter Scully.

Bird in last stage of the complete moult, P1-P8 fully grown, P9 growing halfway and tip of P10 visible. PMS=45. Moult gap in central secondaries almost closed. Note dark iris and blotchy pattern of head streaking. R6 left and R5-R6 right have dark marbling. Such lining on the tail-feathers together with with the pinkish base of bill and dark markings at the gonys indicate a younger adult.