Great Black-backed Gull (Larus marinus)

(last update: July 12, 2015)

Great Black-backed Gull(Larus marinus) 2cy: April 25 2003, Scheveningen, the Netherlands.

This individual is in active moult in the wing-coverts and tail-feathers. A few inner greater coverts and the outermost median coverts have been replaced recently for second generation feathers. Most of the central and inner median coverts have been shed, exposing the bases of the greater coverts. A few outer lower lesser coverts are missing as well. The central tail-feathers have been shed. This 2cy GBbG from the same date and location.

How to detect initiation of the complete moult in spring? Below a 2cy bird to illustrate the very first phase of the complete moult; this bird follows a common moult sequence:
in GREEN: two new median coverts and the innermost new greater coverts are just replaced. Note the buffish base of these feathers, the complete fringe without any wear and the different pattern when compared to juvenile coverts.
in RED: almost all inner and central median coverts are missing.