Data from: Close encounters: Behavioral responses of migrating songbirds to the perceived risk of predation

Migrating birds face competing pressures to travel as quickly and
efficiently as possible while minimizing the risk of predation en route.
Despite the potential importance, antipredator behaviors in migrating
songbirds have been little studied relative to time and energy tradeoffs,
even as humans have introduced novel predators including free-roaming
domestic cats (Felis catus) across the globe. Birds confronted with
predators during stopover can employ antipredator behaviors to reduce
their immediate mortality risk, but doing so may slow refueling or impose
other costs that influence migration. We captured migrating Gray Catbirds
(Dumetella carolinensis) and exposed them to either a live cat, model
hawk, or non-predator control in an aviary experiment to assess their
behavioral responses. Birds moved lower after exposure to a model hawk,
but showed no significant behavioral changes in response to a cat. After
release, we monitored activity levels of a subset of tagged individuals
via the Motus Wildlife Telemetry System. Post-release activity level did
not differ between treatment and control groups, indicating that brief
predator exposure did not exert a persistent effect on this behavior. The
lack of detectable responses to the cat may reflect birds navigating the
tradeoff between antipredator behaviors, which are costly during
migration, and reduction of predation risk. However, it could also
indicate naïveté of young birds to this introduced predator, which may
increase vulnerability to predation during migration. We encourage further
investigation of the influence of prolonged or repeated exposure to
domestic cats on songbird behavior and physiology, and ultimately
migration success.