Antipredatory vigilance usually decreases in groups. The generally accepted "collective detection" explanation implies that because there are more eyes to scan the surroundings for predators, individuals in a group can lower their personal investment in vigilance without increasing their...

Interspecific variations in avian visual systems have been suggested to influence antipredator strategies, yet little empirical evidence exists on how morphological and ecological factors associated with visual properties can constraint predator detection. We investigated antipredator responses...

Several studies showed that animals allow closer approaches (measured through flight initiation distances, FIDs) by potential predators (e.g., humans) in high--predator density areas, which has been explained by habituation effects. We assessed whether this pattern could be produced by not only...

Vigilance has been predicted to decrease with group size due to increased predator detection and dilution of predation risk in larger groups. Although earlier literature reviews have provided ample support for this prediction, an increasing number of studies have failed to document a decline in...

Predator detection is improved when individuals join groups. Theory assumes that the transfer of social information about predators among individuals is immediate and accurate. However, animals in groups space themselves at different distances. Little is known about the shape of the social...

Animals frequently raise their heads to check for danger. In a group, individuals generally raise their heads independently. Earlier models suggest that all group members could gain by coordinating their vigilance, i.e., each member raising its head when others are not. We re-examine these...

Social foraging differs from individual foraging because it alters both resource availability and the forager's behavior. We examined responses of starlings to the presence of conspecifics by manipulating foraging-group density experimentally, while ensuring that each subject's foraging...

Practically all animals must find food while avoiding predators. An individual's perception of predation risk may depend on many factors, such as distance to refuge and group size, but it is unclear whether individuals respond to different factors in a similar manner. We tested whether flocks of...

Group foraging has been proposed to be the most efficient manner with which to exploit habitats with renewing patches as individuals in groups are less likely to revisit patches that have already been exploited recently by others. However, to avoid a group-selection argument, it is necessary to...