An overview and comparative analysis of singing on the nest in North American birds

Bird song is used to defend territories and attract mates and tends to make the singer conspicuous. Singing on the nest (SOTN) has been mentioned since 1904 but has remained largely unexplored. This behavior occurs in 10.1% of breeding birds of North America. Factors that predict the likelihood of SOTN for any species include colonial nesting, incubation sharing and feeding, and taxonomic family. If SOTN is as conspicuous as other forms of singing, this behavior may incur significant costs, such as increased nest predation and parasitism. Data collected from the literature regarding nest vocalizations of adult birds (calls and songs) showed those costs were not significantly different between vocalizing and silent birds. There was greater variance in the rates of nest predation and parasitism for vocalizing birds, which may suggest greater risk. The function(s) of SOTN are not well understood and are mostly untested. Several hypotheses are presented to explain this behavior. This is the first attempt to examine this behavior in any depth and demonstrates the need for further research to explore its function(s) and consequences.