Predation risk and vigilance in the blue tit (Parus caeruleus)
- Cite this article as:
- Lendrem, D.W. Behav Ecol Sociobiol (1983) 14: 9. doi:10.1007/BF00366650
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Feeding blue tits (Parus caeruleus) increase their scanning rates as predation risk increases. However scan durations remain constant. As risk increases the frequency distribution of inter-scan intervals shifts from a regular (rectangular) to a random (exponential) distribution with a 0.5 s constraint on the minimum inter-scan interval.
Cine analysis reveals that this 0.5 s constraint represents the minimum time needed to extract a piece of peanut from a feeder (the ‘handling time constraint’). Manipulating handling times by grinding peanuts to smaller sizes allows tits to adopt random scanning patterns.