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Coordinators: 1cy June 2cy Jan 3cy Jan 4cy / sub-ad Jan adult Jan |
Western Gull occidentalis sub-adult, December 18 2016, San Leandro, Alameda Cty., California, USA. Picture: John Cant.Probably retarded 3rd cycle bird. Ageing can be hard, as some Western Gull retain a very retarded plumage in 3rd cycle, including brown primaries lacking a mirror on P10 and largely brown wing-covert panel. Even the secondaries may be very 2nd gen-like, with dark centres and thin white tips. See e.g. this banded bird 1176-08623. This bird may well be another retarded 3rd cycle, with the secondaries typical for 3rd gen: bold white tips and grey centres. However, note almost all black bill and faded brown primaries, better matching 2nd cycle birds.
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glaucescens Glaucous-winged Gull & Western Gull occidentalis