eWestern Birds

The Quarterly Journal of Western Field Ornithologists

Vol. 54, No. 3
August 2023
Western Field Ornithologists

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Extensive Prealternate Molts in Peruvian Kelp Gulls
Peter Adriaens, Amar Ayyash, and Mars Muusse

ABSTRACT: According to current literature, the Kelp Gull (Larus dominicanus) matures at the same rate and molts according to the same patterns as most other large gulls, such as the American Herring (L. argentatus smithsonianus) and Western (L. occidentalis). The Kelp Gull, however, is widespread through the Southern Hemisphere, with separate populations occupying no fewer than four different climate zones and breeding at different times of the year; the molt of some of those populations appears to have not been studied yet. Here we demonstrate that many immature Kelp Gulls of the Peruvian population undergo much more extensive first and second prealternate molts than has been known so far and achieve an adult-like plumage aspect in as soon as 2.5 years rather than the usual 4. In these respects, these Kelp Gulls recall the Yellow-footed Gull (L. livens) or subspecies heuglini and fuscus of the Lesser Black-backed Gull (L. fuscus).

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