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 R. Moreno-Opo (&) 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.

Evidence that vulture restaurants increase the local abundance of mammalian carnivores in South Africa

“…If providing supplementary carrion for vultures continues to be used as a conservation tool in southern Africa, we recommend that fences could be erected around vulture restaurants to exclude terrestrial scavengers, as used successfully in Europe (Moreno‐Opo et al ., ). We also support suggestions that the most effective and appropriate method of providing supplementary carrion for both avian and terrestrial scavengers is to irregularly deposit carcasses of varying types and sizes at random locations throughout the landscape to simulate a naturally ephemeral and unpredictable food source (Cortés‐Avizanda et al ., , ; Deygout et al ., , ; Donazar, Cortes‐Avizanda & Carrete, ).…”

“…There is also a risk that encouraging aggregations of large numbers of mammalian carnivores at supplementary feeding sites will increase the likelihood of the spread of certain diseases such as rabies (Pain et al ., ; Wright & Gompper, ; Monello & Gompper, ; Ogada et al ., ). This has resulted in fencing being used at some sites to successfully exclude terrestrial scavengers (Moreno‐Opo et al ., ).…”

Management of hunting waste as control measure for tuberculosis in wild ungulates in south-central Spain

“…In this context, differences between wild ungulates observed in the present study can be related to the scavenging behaviour of wild boar. Therefore, avian scavenging feeding points must have appropriate temporal or permanent physical barriers to avoid the entry of mammalian scavengers (Moreno‐Opo et al., ). Additionally, the high fertility rate and the faster population turnover in wild boar are also possible factors related with the differences found between periods in this species, in which the effect of the adequate disposal of big game waste was firstly reflected.…”

The Role of Scavenging in Disease Dynamics

“…High rates of pathogen circulation driven by human management are often associated to overabundance of big game; and in these cases, some infected species often play a role as facultative scavenger (e. g. wild boar, Gortazar et al 2006). In addition, the way big game waste is disposed of may allow for facultative diseasesusceptible scavengers to access infected material (Moreno-Opo et al 2012;Cano-Terriza et al 2018). For instance, in Europe, as in many other parts of the world, the changes occurring across the last 40 years have had a pronounced effect on the environment, creating a dynamic situation where pathogens or new hosts emerge o re-emerge.…”