Fitness Consequences of Interspecific Nesting Associations among Cavity-Nesting Birds

Authors

James C. Mouton, University of MontanaFollow
Thomas E. Martin, University of Montana

Document Type

Article

Journal/Book Title/Conference

The American Naturalist

Volume

192

Issue

3

Publisher

University of Chicago Press

First Page

389

Last Page

396

Publication Date

7-20-2018

Abstract

Interspecific aggregations of prey may provide benefits by mitigating predation risk, but they can also create costs if they increase competition for resources or are more easily detectable by predators. Variation in predation risk and resource availability may influence the occurrence and fitness effects of aggregating in nature. Yet tests of such possibilities are lacking. Cavity-nesting birds provide an interesting test case. They compete aggressively for resources and experience low nest predation rates, which might predict dispersion, but across 19 years of study we found that they commonly aggregate by sharing nest trees. Tree sharing was more common when aspen were more abundant and was somewhat more common in years with higher nest predation risk. Nest success was higher in shared trees when nest predation risk was higher than average. Ultimately, the costs and benefits of aggregating (nest tree sharing) varied across years, and we outline hypotheses for future studies.

Recommended Citation

James C. Mouton and Thomas E. Martin, "Fitness Consequences of Interspecific Nesting Associations among Cavity-Nesting Birds," The American Naturalist 192, no. 3 (September 2018): 389-396.