Avian foraging interactions: an exploration of the competition paradigm.

Abstract

Competition has long been accepted by the scientific community as the major explanation for all species interactions. In recent years, the competition paradigm has come under attack. Scientists have worked to dilute this dogma by demonstrating that the sharing of a limiting resource is not always indicative of competition. We have examined the validity of past investigations into avian interactions. We believe these studies may have suffered from a competitive bias. In our study, we examined if competition was responsible for previously observed interactions, or if other explanations are consistent with these data. We questioned if alternatives such as the looming effect, density dependence, or mating flocking behavior could contribute to the types of encounters observed. We varied amounts of a limited resource on four platform feeders to determine if competition occurred. By observing and categorizing aggressive and non-aggressive bird interactions, we sought to demonstrate if alternatives to competition occurred. Results of our study suggest that competition is not the only contributing factor to bird interactions. Our data also suggests, however, that neither the looming effect nor disease or parasitism play major roles in the interactions of avian species.