Monday, August 7, 8:00-11:30 am
COS 6 - Behavioral ecology
L-13, Lobby Level, Cook Convention Center
Presiders: S Hampton

Can we apply niche partitioning to acoustic communication in a tropical avian community?

Luther, David*,1, 1 University of North Carolina, Chapel Hill, Chapel Hill, NC

ABSTRACT- The evolution of species-specific signals has long been viewed as important in reproductive isolation and speciation. In speciose communities, a species' communicatory signals might suffer interference from similar heterospecific signals, which would decrease the efficiency of intraspecific communication by affecting the detectability and discriminability of conspecific signals. To reduce signal overlap and minimize errors of recognition, signals and signaling behavior might have evolved to partition acoustic space within the acoustic community. This study examines a multi-species avian community in the Amazon to determine whether the timing of signal transmission, the structure of the signal, or both, serve to partition acoustic space and facilitate the successful transmission of communicatory signals. To investigate acoustic partitioning, I conducted standardized, replicated acoustic censuses of the avian dawn chorus in the southern Amazonian rainforest of Brazil. From these recordings, I catalogued every species that can be heard each minute from 0530 to 0830 at each of three pairs of sites 100 m apart in terra firme forest. Using Wildspectra, a sound analysis program, I measured frequency and temporal characteristics of species' signals. I used null models to determine which species avoid signal overlap during the dawn chorus and discriminant function analysis to determine axes that best maximize spacing between species' signals. This study quantitatively describes the acoustic space in which species broadcast their signals and predicts the influence of signal competition on the evolution of species-specific signals.

Key words: Behavioral Ecology, Niche Partitioning, Birds

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