Bibliothèque Tour du Valat

Se connecter

Mot de passe oublié ?
Pas encore inscrit ?

La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Détail

Ajouter au panier

Ajouter au panier

Lien vers la notice

Titre :	Mussel dropping by Carrion and Hooded crows: biomechanical and energetic considerations
Auteurs :	John Davenport, Auteur ; Michael J. A. O'Callaghan, Auteur ; Julia L. Davenport, Auteur ; Thomas C. Kelly, Auteur
Type de document :	Article
Dans :	Journal of Field Ornithology (85(2) JUN 2014)
Article en page(s) :	196-205
Langues:	Anglais
Résumé :	Dropping live mussels (Mytilus sp.) onto hard substrata by Carrion Crows (Corvus corone) and Hooded Crows (Corvus cornix) to access their flesh is a commonly observed behavior from late summer to spring in the United Kingdom and Ireland. Despite previous studies, several aspects of prey-dropping behavior remained incompletely understood. From September 2008 to January 2010, we determined the heights of drops, likelihood of shell breakage from drops at different heights, effect of mussel size on breakability, energetic costs of flying to drop heights, and the energetic costs of transporting mussels from mussel beds to dropping sites. We studied Carrion Crows on the Isle of Cumbrae, Scotland, and Hooded Crows in Cork Harbor, Ireland. Initial experiments were carried out with mussels to determine breakability in relation to size and drop height, and to estimate mussel energy content. Sizes of mussel shells at Hooded Crow dropping sites were compared with those of live mussels from source mussel beds. Adult Carrion Crows (N = 10) dropped mussels from a mean height of 4.7 m, and adult Hooded Crows (N = 21) from 4.8 m. These heights were close to the minimum (4-4.8 m; determined experimentally) required to break all mussel shells on the first drop. Dropping mussels from the minimum height that guarantees breakage reduces handling time and, by minimizing the size of the resulting debris field, likely reduces the risk of kleptoparasitism. Juvenile Hooded Crows (N = 13) dropped mussels onto suboptimal substrates (gravelly mud) from variable heights (mean = 6.1 m) with a low success rate (0% on first drop). This inefficiency could reflect either inexperience or exclusion from prime hard-substrate dropping sites by adults. Foraging Hooded Crows selected larger mussels, dropping no mussels

FAQ

Infos pratiques

Heures d'ouverture et contact

Lundi , mardi et jeudi de 9h à 12h et de 13h à 17h00 : ouverture au public ...

Liens utiles

A-
A
A+