AGE-RELATED CHARACTERISTICS OF FORAGING HABITATS AND FORAGING BEHAVIORS IN THE BLACK PHOEBE (SAYORNIS NIGRICANS)

摘要

We studied how age affects selection of foraging microhabitats, foraging behaviors, and rates of vigilance in the black phoebe (Sayornis nigricans). Juveniles generally perched higher in trees than adults and in areas with higher intensity of light, which may increase the difficulty of visually tracking prey. Juveniles allocated more effort to visual searching prior to a foraging attempt and flew farther than adults to capture a prey item. When at rest on a perch, juveniles monitored the environmentmore slowly than adults, suggesting lower levels of vigilance. In general, our results suggest that differences between ages in foraging behavior of visually guided predators may be influenced by intensity of ambient light in their foraging territories.