Black-headed Gull Chroicocephalus ridibundus

(last update: 3-04-2011)

Below: Black-headed Gull Praha ES11.300, December 26, 2009, Buitenhoflaan, Leiderdorp, The Netherlands (52.167N, 4.528E). Photo: Maarten van Kleinwee.

First-calendar year Black-headed Gull in first-winter (formative) plumage. During the post-juvenile moult, all feathers are replaced except those on the wings and in the tail. The body and head turn completely white, leaving a head pattern similar to adults (with a black ear spot and faint bars from ear to ear and eye to eye across the head). The legs turn orange and the bill orange with a white tip. In the lower image, note the dark outer webs of P8-P10, markings which can be retained in later years. The outer tail feathers are fully white.

(Ringing data: May 29, 2009, Hermanice, Ostrava, Czech Republic, 49'52' N 10'20' E)