Many species of trogons (Trogoniformes: Trogonidae) gather in mixed-gender calling assemblages during the breeding season. These assemblages have been compared to leks and are usually assumed to function in mate choice; however, no field data exist to support this hypothesis. I present five non-mutually exclusive hypotheses for the function of mixed-gender calling assemblages and test the predictions using field data from Black-headed Trogons (Trogon melanocephalus) in a lowland dry forest in Costa Rica. Adult trogons gathered in mobile assemblages of 3-12 individuals that called frequently and chased one another from perch to perch while moving through the forest. Groups formed at sunrise throughout all stages of the breeding cycle and were not significantly male-biased. Both breeding and non-breeding individuals participated in assemblages, and copulations were not observed in assemblages. Prey capture rates of individuals foraging in groups did not differ from those foraging alone. Males called and chased other individuals more often than did females; however, males chased females and other males at equal rates. Assemblages of trogons frequently prospected (investigated potential nest sites and active nests of conspecifics). These data suggest that communal assemblages of calling trogons do not function solely in social mate choice, nor do they enhance foraging efficiency. They may have a role in maintenance of territorial boundaries and selection of future nest sites.
All Science Journal Classification (ASJC) codes
- Ecology, Evolution, Behavior and Systematics
- Animal Science and Zoology