Try and Try Again: Nest Predation Favors Persistence in a Neotropical Bird
James J. Roper
Abstract
Successful reproduction for birds in systems with high nest predation rates may be explained by two alternatives. The first hypothesis is that nest-predation is avoided, perhaps by nest-site or territory selection, parental behavior and so on. This hypothesis renders the prediction that within-pair consistency, or repeatability, in nesting success occurs and is due to nest predation avoidance. The alternative hypothe- sis is that pairs vary in their ability to nest again following predation, and generates the prediction that dif- ferential reproductive success among pairs is due to renesting ability, not predation avoidance. To test these alternatives, nest success, renesting intervals, breeding season length, and nesting history were stud- ied in the Western Slaty Antshrike (Thamnophilus atrinucha) in central Panama. Reproductive success is low; with a survival rate of 0.91 day -1 , only one in eight nesting attempts are successful and essentially all nest failures are due to nest predation. Pairs showed neither consistency in nesting success nor variation in nest