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Diet specialization in a generalist population: the case of breeding great tits Parus major in the Mediterranean area

Pagani-Núñez, E.; Valls, M.; Senar, J.C.

Authors

M. Valls

J.C. Senar



Abstract

The analysis of diet specialization provides key information on how different individuals deal with similar food and habitat constraints within populations. Characterizing parental diet specialization at the moment of breeding, and the consistency of these preferences under different levels of effort, may help us to understand why parents exploit alternative resources. We investigated these questions in a species commonly considered a generalist: a breeding population of Mediterranean great tits Parus major. Our aim was to determine whether they are specialists or generalists at the pair level, and the consistency of this behaviour under different levels of effort. Using proportional similarity and mean pairwise overlap indices, we found that parents showed great variability in prey selection between territories. That is, they displayed a small niche overlap. Interestingly, the most specialized breeding pairs showed a tendency to have larger broods. Additionally, we experimentally manipulated brood size and found that parents showed high short-term consistency in their foraging behaviour. They precisely adjusted the number of provisioning trips to the number of nestlings, while they were unable to modify prey proportions or prey size after brood size was changed. We can therefore characterize their foraging strategies as highly consistent. Our results suggest that although the great tit may be considered a generalist at the species or population level, there was a tendency for trophic specialization among breeding pairs. This high inter- and intrapopulation plasticity could account for their great success and wide distribution.

Journal Article Type Article
Acceptance Date Apr 26, 2015
Online Publication Date May 17, 2015
Publication Date 2015-11
Deposit Date Nov 2, 2022
Journal Oecologia
Print ISSN 0029-8549
Publisher Springer
Peer Reviewed Peer Reviewed
Volume 179
Issue 3
Pages 629-640
DOI https://doi.org/10.1007/s00442-015-3334-2
Keywords Foraging behaviour, Niche overlap, Niche partitioning, Prey selection, Provisioning rates
Public URL http://researchrepository.napier.ac.uk/Output/2946673