Birds of Indian Subcontinent

Test of the Ecological Basis of Cooperative Breeding in Red-Cockaded Woodpeckers

Publication Type:Journal Article
Year of Publication:1992
Authors:Walters, JR, Copeyon, CK, Carter, III, JH
Journal:The Auk
Date Published:1992
ISBN Number:00048038
Keywords:Picidae, Picoides, Picoides borealis
Abstract:In many cooperatively breeding birds, the primary reason that helpers remain on the natal territory rather than disperse to breed independently may be to gain an advantage in competing for high-quality habitat. We hypothesized that cavities excavated in living pines, because they require much time to construct, are the critical determinant of habitat quality that has led to cooperative breeding in Red-cockaded Woodpeckers (Picoides borealis). These woodpeckers rarely colonize sites that lack existing cavities. To test our hypothesis we drilled cavities in 20 unoccupied sites. Eighteen were occupied subsequently, but none of 20 control sites were used. The manipulation added 12 new social units (breeding pairs or unpaired territorial males) to the population. New groups mostly comprised previous helpers and dispersing first-year birds. These results support our contention that variation in habitat quality dependent on the presence or absence of cavities is the ecological basis of group formation in Red-cockaded Woodpeckers. Cavity construction may be used to increase the number of groups in a population, and to prevent territory abandonment when bird-constructed cavities are lost.
Short Title:The Auk
Taxonomic name: 
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith