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A study reveals the large movements of Griffon vultures in search of food and the factors on which they depend, highlighting the need to focus its conservation at a regional or state level.
Among the scavenger birds of southern Europe, the Griffon vulture (Gyps fulvus) is a key species due to the important ecosystem services it provides through the elimination of carcasses of livestock and wild ungulates that die in the field, without economic cost and without generating greenhouse gas emissions. In addition, along with the rest of avian scavengers, it has become a key attraction for nature tourism, which generates significant income in rural economies. Despite its importance, we still know very little about essential aspects of its movement ecology, which is fundamental in conservation management.
A study led by researchers from the Universidad Miguel Hernández, with the participation of scientists from the Research Group in Game Resources and Wildlife Management of the Instituto de Investigación en Recursos Cinegéticos (IREC – CSIC, UCLM, JCCM), has analyzed the spatio-temporal information provided by 127 Griffon vultures tagged with GPS devices in five different regions of mainland Spain.
The data obtained indicate that griffon vultures move throughout the year over very large areas, reaching 5.000 km2 on average and reaching sometimes almost 10.000 km2 , which means an average displacement of 1.700 kilometers per month. The information obtained also reveals important differences in the home-range of vultures depending on different factors, such as the breeding area, seasonality, or the sex of the individual.
Quantifying the use of space by wildlife species that are highly mobile and dependent on unpredictable trophic resources such as vultures is essential to improve the conservation management of their populations. The maps in this figure show the range of movements of various individuals of Griffon Vultures (N) from 5 breeding regions in mainland Spain.
For example, individuals from the northern breeding regions, in the Pyrenees, the Ebro Valley, and the Central System, showed smaller home ranges and traveled shorter monthly distances than populations located more southerly, such as the mountains of Cazorla or Cádiz. On the other hand, the foraging areas were larger in spring and summer than in winter and autumn, which could be related to differences in flight conditions and food needs associated with reproduction.
Finally, the extensions of the vultures' home ranges also showed differences depending on the sex of the individual. Females showed larger foraging areas than males, so the latter tend to use similar areas throughout the year. This can determine asymmetries in the risk of both sexes regarding mortality factors caused by human activities.
«Based on these results, it is of great interest to delve into how the patterns of space use vary when there are changes in environmental conditions", say the authors of the study. In the long term, it is essential to anticipate how the scenarios of radical changes that are taking place in rural economies can affect the viability of scavenger bird populations.
The researchers point out that “rural economies are undergoing changes in two directions, which are actually sides of the same coin. On the one hand, we have the intensification of livestock farming and, on the other, rural abandonment, which entails the disappearance of traditional uses and the renaturation of large areas of the Iberian Peninsula.”. Because of that, "long-term monitoring of vulture populations with continued GPS tagging of individuals and examination of individual response to these changes will be necessary«.
The results obtained from this work show that the management of wildlife species that exploit such large areas cannot be considered at the local level. Conservation strategies are necessary to guarantee the existence of trophic resources and minimize mortality risks on a practically continental scale, for which the collaboration of regional and even national administrations is required to avoid asymmetries in the application, for example, of sanitary regulations related to the elimination of livestock carcasses.
The scientific publication of this research is available at:
- Morant, J., Arrondo, E., Sánchez-Zapata, JA, Donázar, JA, Cortés-Avizanda, A., De La Riva, M., Blanco, M., Martínez, F., Oltra, J., Carrete , M., Margalida, A., Oliva-Vidal, P., Martínez, JM, Serrano, D., Pérez-García, JM 2023. Large-scale movement patterns in a social vulture are influenced by seasonality, sex, and breeding region. Ecology and Evolution 13, e9817.
