AVIS-IBIS

Birds of Indian Subcontinent

Bright Plumage in the Magpie: Does It Increase or Reduce the Risk of Predation?

Publication Type:Journal Article
Year of Publication:1997
Authors:Götmark, F
Journal:Behavioral Ecology and Sociobiology
Volume:40
Issue:1
Date Published:1997
ISBN Number:03405443
Keywords:Accipiter, Accipiter gentilis, Accipitridae, Corvidae, Garrulus, Garrulus glandarius, Pica, Pica pica
Abstract:Conspicuous color patterns in birds may lead to increased risk of predation. Alternatively, bright birds may be aposematic or unprofitable prey, which leads to decreased predation. During four autumns, I examined whether the black-and-white plumage of (stuffed) magpies Pica pica increases or reduces the risk of attack by migrating goshawks Accipiter gentilis. Attack risk was higher for normal magpies than for cryptic, brown magpies whether the mounts were placed near one another or far apart. However, the brown magpie may have been avoided because of its novelty. For magpies and cryptic jays Garrulus glandarius exposed together, the attack risk was similar. In 2 years, magpie and jay mounts were also exposed far apart. In 1994, with an invasion of migrating jays, attack risk was much higher for jays than for magpies. In 1995, with a normal density of jays, hawks attacked the magpies more often. The results demonstrate frequency-dependent prey selection by goshawks, which would influence any predation cost of bright plumage. The attacks on normally colored magpie mounts suggest that magpies are not aposematic. Trials with photographs and human observers indicated that normal magpies were somewhat easier to detect than jays. The plumage of the magpie possibly increases the risk of predation, but may be favoured by sexual or social selection.
URL:http://www.jstor.org/stable/4601295
Short Title:Behavioral Ecology and Sociobiology
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith