Linking sanitary and ecological requirements in the management of avian scavengers: effectiveness of fencing against mammals in supplementary feeding sites

Abstract

In order to ensure that the objectives behind the conservation of biodiversity are fulfilled it is essential that policies of all stakeholders are compatible. This is the case of the application of sanitary measures for the management of animal by-products and the negative effects that such restrictions had on the population dynamics and behavioural ecology of the avian scavengers’ guild. Thus, measures that allow these species to feed and that reduce risks of disease transmission must be put into practice. This study aims to improve the technical implementation of one of the commonest tools employed in the conservation of avian scavengers: supplementary feeding stations. We evaluated the permeability of three types of fences in experimental feeding stations to determine which of the models prevent non-target species from accessing the food provided. We compared results from fenced-off feeding stations with those from random points in unfenced-off sites. The results showed that two of the models (high and low nets) were the most effective avoiding facultative mammal scavengers from gaining access into the exclosure for over two months and for 7–8 inputs of food. Avian scavengers were able to access food regardless of the type of exclosure, which did not determine the abundance of birds or the species present. The carrion consumption by non-target species can be reduced by affordable and sustainable means. We suggest proposals to optimize the management of supplementary feeding stations for threatened avian scavengers and for the design of fenced exclosures.