Authors: Katherine A Jones John R Krebs Mark J Whittingham
Publish Date: 2009/05/26
Volume: 63, Issue: 9, Pages: 1319-1329
Abstract
The relationship between body mass and reactions speed in response to a predatory threat is poorly understood Theory predicts that different vigilance patterns are optimal for the detection of different predator types We suggest that birds of different individual state might also differ in their speed of response dependent upon predator type We used laboratory trials of wild caught chaffinches Fringilla coelebs to determine how between individual differences in chaffinch behaviour and state correlate with latency to react to a ground predator model domestic cat thus providing a comparison with previous work in the same model system using aerial predator models In experiment 1 we observed chaffinch responses to a moving cat model simulating a stalking predator In experiment 2 we used a camouflaged cat model simulating an ambush predator Both experiments show evidence suggesting heavier individuals which previous literature has linked to impaired flight performance responded more quickly to the model cat Heavier individuals also had shorter interscan intervals In contrast to a previous study both experiments found individuals with a higher intake rate were not faster at responding to the cat model In addition individuals in experiment 1 that head turned more while scanning were slower to respond to the stalking cat model Our work suggests that although heavier individuals may have impaired escape performance they appear to show behavioural compensation by allocating more attention to antipredator behaviour and by modifying their interscan intervals resulting in faster response times to a ground predator We suggest more experiments investigating response time to different predatory types and explicitly manipulating state to elucidate cause and effectWe would like to thank Matt Denny Matt Wood and Julian Howe for their help catching chaffinches We also thank Dave Wilson for animal husbandry Katherine Jones was funded by a British Biological Sciences Research Council Studentship and Mark Whittingham by a British Biological Sciences Research Council David Phillips Research Fellowship
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