Resource defense and territorial behavior of male and female Ruby-throated Hummingbirds (Archilochus colubris)

Abstract

Ruby-throated Hummingbirds (Archilochus colubris) defend a territory based on the availability of their food source. Male hummingbirds are known to be more aggressive than females as they chase away any intruders near their territory, while females have been reported to share a territory and their food source in addition to exhibiting aggressive behavior at food resources. We explored how the sex of the defending hummingbird and the amount of resources in their territory affected hummingbird aggression. We predicted that male hummingbirds would chase both male and female hummingbirds equally, whereas female hummingbirds would chase away more males than females. We also predicted that the most aggression would take place at our intermediate- resource sites because these represent the best tradeoff between resource benefits and energetic costs of defense (Rousseu et al. 2014). Results showed that intermediate-resource sites had more male-female chases while low and high resource levels were associated with more female- female chases. We also found that the most aggressive behavior occurred at low-resource sites.