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In recent decades, intensive techniques of livestock raising have flourished, which has largely replaced traditional farming practices such as transhumance. These changes may have affected scavengers’ behaviour and ecology, as extensive livestock is a key source of carrion. This study evaluates the spatial responses of avian scavengers to the seasonal movements of transhumant herds in south-eastern Spain. We surveyed the abundance of avian scavengers and ungulates, and analysed the factors affecting the space use by 30 GPS-tracked griffon vultures (Gyps fulvus). Griffons’ foraging activity increased in the pasturelands occupied by transhumant herds, which implied greater vulture abundance at the landscape level during the livestock season. In contrast, facultative scavengers were more abundant without transhumant livestock herds, and the abundance of wild ungulates did not change in relation to livestock presence. We conclude that fostering transhumance and other traditional farming systems, to the detriment of farming intensification, could favour vulture conservation.

Intentional poisoning is a global wildlife problem and an overlooked risk factor for public health. Managing poisoning requires unbiased and high-quality data through wildlife monitoring protocols, which are largely lacking. We herein evaluated the biases associated with current monitoring programmes of wildlife poisoning in Spain. We compared the national poisoning database for the 1990–2015 period with information obtained from a field experiment during which we used camera-traps to detect the species that consumed non-poisoned baits. Our findings suggest that the detection rate of poisoned animals is species-dependent: Several animal groups (e.g., domestic mammalian carnivores and vultures) tended to be over-represented in the poisoning national database, while others (e.g., corvids and small mammals) were underrepresented. As revealed by the GLMM analyses, the probability of a given species being overrepresented was higher for heaviest, aerial, and cryptic species. In conclusion, we found that monitoring poisoned fauna based on heterogeneous sources may produce important biases in detection rates; thus, such information should be used with caution by managers and policy-makers. Our findings may guide to future search efforts aimed to reach a more comprehensive understanding of the intentional wildlife poisoning problem.

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Transhumance is an extensive livestock technique that consist on the seasonal movement of herds to take advantage of natural high-quality pastures. Extensive pastoralism modulates the landscape, provide ecosystem services as well as feeding opportunities for scavengers. However, transhumance is in decline mainly due to socio-economic changes, so the availability of food for scavengers may be changing. With the aim to evaluate the remaining effect of transhumance, we explored the changes that occur in a summer pasture ecosystem according to the presence or absence of livestock. The study was located in a high plateau of pastures in the south of the Iberian Peninsula, located in the Natural Park of Sierra de Cazorla, Segura y las Villas where about 35,000 units of livestock, mainly sheep, move there to graze in summer. We evaluated the changes in the abundance of obligate and facultative scavengers by field surveys, as well as the response of local wild ungulates in presence and absence of livestock. We also evaluated the individual foraging behavior of the main scavengers by GPS monitoring of 30 adult griffon vultures (Gyps fulvus) for four years. Surveys shown a positive populational response of griffon vultures in presence of livestock and an increase of GPS locations, especially noteworthy in non-breeding individuals. However, facultative scavengers and wild ungulates abundances remain unaltered throughout the year. The combination of census sampling and GPS monitoring allowed us to better understand the ecosystem dynamics. Traditional extensive livestock farming has a functional ecological response in scavengers, so current changes in this practice may affect them in future scenarios.