Data from: Experimentally induced anti-predator responses are mediated by social and environmental factors

Nest predation is a common cause of reproductive failure for many bird
species, and various anti-predator defense behaviors have evolved to
reduce the risk of nest predation. However, trade-offs between current
reproductive duties and future reproduction often limit the parent’s
ability to respond to nest predation risk. Individual responses to
experimentally increased nest predation risk can give insights into these
trade-offs. Here, we investigate whether social and ecological factors
affect individual responses to predation risk by experimentally
manipulating the risk of nest predation using taxidermic mounts in the
cooperative breeding Seychelles warbler (Acrocephalus sechellensis). Our
results show that dominant females, but not males, alarm called more often
when they confront a nest predator model alone than when they do so with a
partner, and that individuals that confront a predator together attacked
more than those that did so alone. Dominant males increased their
anti-predator defense by spending more time nest guarding after a
presentation with a nest predator, compared to a non-predator control, but
no such effect was found for females, who did not increase the time spent
incubating. In contrast to incubation by females, nest guarding responses
by dominant males depended on the presence of other group members and food
availability. These results suggest that while female investment in
incubation is always high and not dependent on social and ecological
conditions, males have a lower initial investment, which allows them to
respond to sudden changes in nest predation risk.