Predation risk and vigilance in the blue tit (Parus caeruleus)

✍ Scribed by Dennis William Lendrem

• Book ID: 104742547
• Publisher: Springer
• Year: 1983
• Tongue: English
• Weight: 499 KB
• Volume: 14
• Category: Article
• ISSN: 0340-5443
• DOI: 10.1007/bf00366650

✦ Synopsis

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.