Post-Predation Parental Behavior of Boreal Songbirds.

Songbirds have a high nest failure rate, with most failed nest attempts caused by predation. While songbird behavior before and during predation events has been documented, post-predation behavior has not. We observed post-predation behavior from 36 complete predation events (all fledglings or eggs taken by predator resulting in an empty nest) of nine songbird species by using video monitoring. We examined the time for the parent to abandon the empty nest and the number of return visits the parent made before abandoning the empty nest. Increased nestling age at the time of predation resulted in parents abandoning the nest sooner and making fewer return visits to the nest post-predation. There was weak evidence that parental behavior after predation differed based on the species of predator that destroyed the nest. Other post-predation behaviors included parents returning to eat eggshells, incubation of empty nests, and food provisioning. The extended time required to leave a nest after it has failed suggests birds have a compulsion that needs to be 'switched off' prior to abandoning a nest. Why birds engage in such behaviors post-predation is unclear but indicates a lack of selection pressure to evolve an 'immediate response' to predation. Presumably, delays in subsequent re-nesting attempts caused by such behaviors are minor but this hypothesis warrants further research. [ABSTRACT FROM AUTHOR]