|
|
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, although the secondaries in this bird have a 2nd gen-like look: brown centres with thin white tips are visible below the greater covert row. The primaries are blackish brown lacking any tips and no mirror on P10 (but a view on the innermost primaries would be welcome). The rectrices are blackish with thin white tip. Despite these indications for 2nd cycle, the wing-covert panel with vermiculated greater coverts and largely grey scapular region lacking 2nd gen-like scaps may be pointers for 3rd cycle. Anyway, 'sub-adult' nicely covers such birds.
|
glaucescens Glaucous-winged Gull & Western Gull occidentalis