La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	Identification and ageing of Black-browed Albatross at sea
Auteurs :	Frédéric Jiguet, Auteur
Type de document :	Article
Dans :	British Birds (93(6) June, 2000)
Article en page(s) :	263-276
Résumé :	The Black-browed Albatross Diomedea melanophris is the most frequently recorded of all vagrant albatrosses in the North Atlantic. This paper provides guidelines to identify the species and to help in ageing immatures at sea. The Black-browed Albatross is best identified by underwing pattern and general silhouette, with bill pattern, when visible, often diagnostic. Individuals can be aged by using a combination of primary moult pattern and bill coloration. The primary moult is basically biennial, with two distinct phases: the three outer primaries (P8-10) are always moulted descendantly in year one, and P5-7 always ascendantly in year two. The first primary moult of juveniles starts during the second winter. Contrast between old and new outer primaries is often very obvious on immatures, so that precise scrutiny of primary ages at close range is usually not necessary. Bill coloration is variable, and there is some overlap between consecutive immature ages, but, taking into account the bienniality of the primary moult, bill pattern allows correct ageing. The underwing whitens with age, but remains much too variable, even when adult, to constitute a reliable criterion when ageing.

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