The Significance of Mating System and Nonbreeding Behavior to Population and Forest Patch Use by Migrant Birds

Migratory birds are birds of two worlds, breeding in the temperate zone then living as tropical birds for most of the year. We show two aspects of this unique biology that are important considerations for their conservation. First, habitat selection for breeding must include their need for extra-pair mating opportunities. Second, non-breeding distributions in tropical latitudes are poorly known. Both geographic distribution and over-wintering habitat are much more limited than generally thought, suggesting that many species may be in more danger of population limitation there than presently thought. Tropical population limitation can result in migratory birds being eliminated from forest fragments, not due to fragmentation per se but to the need for extra-pair mating opportunities.