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Title
  • en Individual differences in nest defense in the colonial breeding Black-tailed Gulls
Creator
Accessrights open access
Rights
  • en The original publication is available at www.springerlink.com
Subject
  • Other en Aggressiveness
  • Other en Black-tailed Gull
  • Other en Coloniality
  • Other en Group living
  • Other en Nest defense
  • Other en Neighbor
  • Other en Mobbing
  • NDC 468
Description
  • Abstract en Often in colonial seabirds, all colony members are believed to defend against nest predators and experience equal nest predation risk. However, the variation of defense behavior among members and its reproductive consequences are largely unknown. We investigated 1) individual variation in the nest defense of breeding Black-tailed Gulls Larus crassirostris against a natural egg predator, the Jungle Crow Corvus macrorhynchos and 2) how this behavioral variation affects an individual's own nest predation risk and that of their neighbors. Results were compared between two years where crow attack levels were manipulated to average 5 and 22 times normal rates ("low" and "high" predation risk years, respectively) by the placement of varying numbers of artificial nests containing unguarded eggs at the perimeter of the gull colony. In both years, 23-38% of parents, mostly males, showed "aggressive" defense behavior (strikes or chases) against crows and decoys. Other "non-aggressive" gulls showed no defense. In the year of low predation risk, intrusion rates by crows (landing within 0.5 m of an individual gull's nest) were similar for aggressive and non-aggressive gulls. In the year of high predation risk, however, the rates of intrusion for aggressive gulls (4%) and for non-aggressive gulls with an aggressive neighbor (37%) were significantly lower than for non-aggressive gulls without an aggressive neighbor (76%). These results indicate that aggressive individuals reduce nest predation risk for themselves and conspecific neighbors in a colonially breeding species.
Publisher en Springer Berlin / Heidelberg
Date
    Issued2010-08
Language
  • eng
Resource Type journal article
Version Type AM
Identifier HDL http://hdl.handle.net/2115/46866
Relation
  • isVersionOf DOI https://doi.org/10.1007/s00265-010-0938-8
Journal
    • PISSN 0340-5443
      • en Behavioral Ecology and Sociobiology
      • Volume Number64 Issue Number8 Page Start1239 Page End1246
File
Oaidate 2023-07-26