La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	Do predators cause a change in passerine movement patterns as indicated by mist-net trapping rates? (2006)
Auteurs :	Alfréd Trnka, Auteur ; Pavol Prokop, Auteur
Type de document :	Article
Dans :	Ardea (94(1) Spring, 2006)
Article en page(s) :	71-76
Résumé :	Predation can act as a selective pressure on birds, which may be expected therefore to change habitat use in the presence of predators. To examine this, experiments were performed using Marsh Harrier Circus aeruginosus silhouettes. The effect of predators on movement patterns and capture efficiency of mist nets were investigated in two unrelated passerines, Reed Warblers Acrocephalus scirpuceus and Tree Sparrows Passer montanus, in natural reed beds and bushes, respectively Birds were trapped at the end of the nesting period in eight study plots with intermittently placed silhouettes of raptors. We found that the presence of a predator depressed capture rates in Tree Sparrows, but not in Reed Warblers. Instead, raptor presence affected the vertical spatial distribution of this species. Apparently, each species responded to aerial predators in a different way, which may be species' specific or dependent on habitat type, or both. These results, therefore, strongly suggest that mist-net studies on capture rates and movement patterns of passerines can be affected by the presence of aerial predators.

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