Vigilance and Perception of Flock Size in Foraging House Sparrows (Passer Domesticus L.)
1984; Brill; Volume: 90; Issue: 4 Linguagem: Inglês
10.1163/156853984x00146
ISSN1568-539X
AutoresMark A. Elgar, Paul J. Burren, Melissa Posen,
Tópico(s)Animal Vocal Communication and Behavior
ResumoPerception of flockmates is clearly important if individuals' vigilance behaviour depends as much on the behaviour of other individuals as on the flock size. We attempted to evaluate the importance of flockmate perception in the scanning behaviour of free-living house sparrows Passer domesticus by observing them at an artificial feeder. Typically, sparrows would await on an adjacent wall, where they could see all the birds in the feeder, before hopping down to forage. Individuals' inter-scan time increased with flock size, but when a barrier was placed across the feeder, preventing sparrows in the feeder from seeing the other side, individuals scanned according to the number of visible sparrows, rather than the total number in the feeder. When two smaller feeders were placed at different distances apart, individuals greater than 1.2 m apart scanned independently of each other.
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