Black-headed Gull Chroicocephalus ridibundus

(last update: 3-01-2016)

Black-headed Gull - 2cy October

This section deals with second-calendar year Black-headed Gulls in the month of October.

Introduction

In October, second-calendar year Black-headed Gulls are in ’adult winter plumage. This second winter plumage is adult like but a small minority of gulls can be distinguished as ‘second winter plumage’ from 2cy August-3cy February by dark markings on tertials, outer primary coverts and alula.

Adult winter plumage is characterized as follows:   

• Head: white with dark ear spots and traces of vertical bars above eyes. Moult of head starts with forehead, developing backwards.
• Hindneck and underbody: white
• Bare parts: bill deep red with dark tip, legs dark reddish, iris dark brown
• Upperwing ‘tricoloured’:
• p7-p10: white (with black edge of outer web not reaching tip on p10)
• p5-p10: black-tipped, extending on to inner edge of inner web
• p4-p7: with white extreme tip
• p1-p6: grey with blackish-grey innerwebs on p1-p5
• secondaries: grey with white tips
• Underwing: outer primaries white, dark tipped, mid primaries dark
• Tail: all white

Most of the description follows: 
P.J. Grant: "Gulls, a guide to identification".
K.M.Olsen: “Gulls of Europe, Asia and North America”.