Automated feeders: new technology for food supplementation experiments with mammals

Abstract

Experimental manipulations of food supply in wild populations are often confounded by a number of factors, such as induced immigration to local populations receiving food supplements and intraspecific competition for access to feed stations. Here, we describe newly developed automated feeding stations, designed to dispense weighed food supplements to specific experimental animals. The feeders incorporate a data logger that records the identification and weight of each animal and the time of the visit to the feeder.

Using the common brushtail possum (Trichosurus vulpecula) as a model medium-sized mammal, we present results of an 18-month field trial. Each free-ranging experimental possum was fitted with a collar containing a transponder chip, allowing them access to a feeder. During the field trial, experimental possums were found to show a significant increase in body mass compared with control animals, which showed a slight decrease in mass. Body masses recorded by the feeders for experimental possums did not differ from mass data recorded during live-trapping sessions.

The automated feeding stations represent an advance over previous methodology and the first time supplementary food has been delivered in a controlled automated fashion in a wild mammal population. The implications of the feeders to future studies of resource supplementation in mammals are discussed.