SPECIES-SPECIFIC NEST SITE SELECTION BY BIRDS IN ANT-ACACIA TREES

Examined nest site differences among 4 bird species nesting in Acacia collinsi trees with ants that may deter nest predators at Palo Verde, Costa Rica. Rufous-naped wrens Campylorhynchus rufinucha showed a non-random preference for nesting in trees with unusually active ant colonies. They nested most commonly in trees with the most active ant species Pseudomyrmex spinicola and P. nigrocinctus, when they nested in trees with a less active species of ant (P. flavicornis), these trees usually contained colonies that were more active than the average for their species. Streak-backed oriole Icterus sclateri, yellow-olive flycatcher Tolmomyias sulphurescens and great kiskadee Pitangus sulphuratus used trees for nests at random with respect to ant species and consequently these ants were much less active than ants on rufous-naped wren nest trees. Nest predation on eggs in artificial nests was higher in acacia than non-acacias due to pecking by rufous-naped wrens, suggesting that wrens may be inhibiting other bird species from nesting in the most protected nest sites. -from Authors