Heuglin's Gull (L. heuglini / antelius)
(last update:
Larus fuscus graellsii 93 sub-adult, May 16 2006, Moerdijk, the Netherlands.
Trapped on the nest. Sex: undetermined. Vermillion orbital ring. Black on P3-P10. P4 with broken sub-terminal band. No mirror on P9. Broad sub-terminal band on P10. Scoring following heuglini classification (Buzun, 2002): P10 mirror on outer-web = closed; P10 mirror on inner-web = closed. Much diffuse black on upperwing primary coverts (bird therefore classified 'sub-adult'), but no black on the bill. Orange gape. Note sharply demarcated black spots in centres of secondaries. P10 pattern does not allow scoring of contrast between underwing greater primary coverts and base of P10, as the pale base of P10 completely hides behind these primary coverts.
