Preferred nest site characteristics reduce predator-specific predation risk in a canopy-nesting raptor

Abstract

Habitat features influence nest survival and, as a result, identifying relationships between habitat characteristics and nest survival remains a central focus among studies of avian reproduction. In cases where nest predation is the main cause of failure, knowing how the habitat affects predation risk may provide managers with a tangible means by which to improve reproductive success. The Mississippi kite (Ictinia mississippiensis) is a species of regional conservation concern due to small population sizes and high rates of nest failure. We monitored Mississippi kite nests, documented causes of nest failure, and examined relationships between habitat features and predator-specific patterns in nest predation in a floodplain forest in east-central Arkansas. We identified Texas ratsnakes (Pantherophis obsoletus) and owls (Strigidae) as the dominant nest predators and predation by each was influenced by different habitat features. Ratsnake predation was greater in areas with fewer overstory trees and when kite nests were positioned farther above the tree canopy. Owls were more likely to depredate nests farther from the forest edge and nests that had less canopy coverage around them. Our results illustrate that the nest site characteristics preferred by kites reduce nest predation risk, indicating most of the management actions proposed to promote kite nesting are likely to create or maintain quality habitat for this species in the Mississippi Alluvial Valley. Beyond knowing the main causes of nest failure in kites, our results may also provide a glimpse into threats faced by mid-story and other canopy-nesting birds, a guild for which very little information exists regarding causes of nesting failure. © 2014 The Wildlife Society.