Abstracts » Zoology and wildlife conservation

Back to the basics of anti-predatory vigilance: the group-size effect

Article Abstract:

An experimental study of vigilance in mixed flocks of dark-eyed juncos and American tree sparrows does not support the many-eyes hypothesis, which claims that the group size and the levels of individual vigilance are inversely related. The hypothesis suggests that an increase in group size allows an individual forager to curb its vigilance period without affecting the group's potential to identify an attack. The hypothesis assumes a collective detection, whereby detection even by one individual alerts the group, and a behavioral monitoring, whereby individuals determine their own vigilance by monitoring that of their group mates. The experimental results reject both the assumption.

Analysis, Animal attacks

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Back to the basics of antipredatory vigilance: Can nonvigilant animals detect attack?

Article Abstract:

It is shown that the nonvigilant dark-eyed junco Junco hyemalis can detect an approaching raptor at considerable distance. However its nonvigilant capabilities of detecting attacks, is not as good as when it is fully vigilant. It is suggested that predator detection can be a trade-off in many animals, between low-cost, lower-quality vigilance, and high-cost, high-quality vigilance.

Behavior, Predatory animals

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Testing for peripheral vigilance: Do birds value what they see when not overtly vigilant?

Article Abstract:

The way in which the 'peripheral vigilance' interacts with overt vigilance and the collective detection of threats is tested. The results suggest that juncos value peripheral vigilance and that scanning patterns are affected by interactions between peripheral vigilance and overt scanning behaviour.

United States, Science & research, Animal psychology, Vigilance (Psychology)

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