Larus cachinnans

(last update: February 16, 2013)

Coordinator:
Peter Adriaens (Belgium)
Ies Meulmeester (Netherlands)

Home

cachinnans plumages

Larus argentatus 4P30 adult (plus hybrid offspring 7P84 & 7P85), May, July & December 2014, Poland. Picture: Łukasz Bednarz ringing team.

Please visit Łukasz's BLOG for beautiful drawings and up-to-date gull news from eastern Poland: Wildlife art and illustration

Location: Zastów Karczmiski, Poland - colony at the banks of the Middle Vistula river.
In 2004 240 breeding pairs (95% cachinnans, <5% argentatus). (Ornis Fennica 2011 88, 80-89) and in 2012 592 pairs (90% cachinnans, <10% hybrid / argentatus) and possibly Larus michahellis (pers comm. Łukasz Bednarz).

Middle Vistule river is a location where several taxa breed: see composition. Since this is a mixed breeding population where hybridisation is not uncommon, the ringing centre in Poland decided to label birds "Larus argentatus sensu lato". Still bulk of the breeding birds in Middle Vistula region show features of cachinnans.

below: Larus argentatus 4P30 adult, May 06 2014, Zastów Karczmiski, Poland. Picture: Łukasz Bednarz ringing team.

Breeding female trapped at the nest, showing obvious argentatus features. Adult, with no speckling in iris. Orange-red orbital ring and gape. No red on upper mandible; faint black on the upper and no black on the lower mandible. Pink legs with yellow hue.
Deep white tongue on P10 (medial band less broad than white tip as in cachinnans; still much black on innerweb of P10 which runs up to the primary coverts over a broad range), P9 with thayeri pattern, no black on P5; no spot on P4. P1-P2 dropped, PMS=2.

below: Larus argentatus 4P30 adult, May 06 2014, Zastów Karczmiski, Poland. Picture: Łukasz Bednarz ringing team.

Note 'high, stubby bill' and pale yellow staring eye. Legs obvious yellowish. Two begging chicks from this years nest: 7P84 & 7P85. Mother is female argentatus 4P30 and father is cachinnans.

below: hybrid cachinnans x argentatus 7P84 1st cycle, December 04 2014 Witoszowka Reservoir, Poland. Picture: Łukasz Bednarz ringing team.

One of the chicks from this years nest: 7P84. Mother is female argentatus 4P30 and father is cachinnans.