La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	High profit at high risk for juvenile Dunlins Calidris alpina stopping over at Helgoland (German Bight)
Auteurs :	V. Dierschke, Auteur
Type de document :	Article
Dans :	Ardea (86(1) 1998)
Article en page(s) :	59-69
Résumé :	During autumn migration, up to 1100 juvenile Dunlins Calidris alpina per day forage on the island of Helgoland (SE North Sea). Beds of washed up wracks and kelp sire used as a feeding habitat where they take kelp fly larvae (Coelopidae) at a high rate (17.8 larvae min(-1)). This high energy intake allows rapid fattening (1.7-3.3 g day(-1)) and short lengths of stay (about 4-5 days), leading to a high daily turnover of individuals (0.2-0.7 day(-1)). Despite the good conditions for meeting energetic requirements, staging at the island incurred a high depredation risk from migrating birds of prey. Different feeding priorities might be one reason why most adult Dunlins avoid Helgoland as a staging site and instead aggregate at large staging areas such as the Wadden Sea, where individual depreciation risk is more than 50 times less.

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