In this study we explore the feedback between disease and behavior. On one hand we investigate different risk factors (e.g. poisoning or viral pathogens) that affect Griffon Vultures (GV, Gyps fulvus) movement and survival. On the other hand, we explore how a vulture’s individual behaviors pre-dispose them to different threats such as infection by pathogens, poison or injury.
The GV is locally endangered in Israel and the Middle East. Despite intense efforts by the Israeli Nature Protection Authority (INPA) to protect this species the population is declining. For instance, from 110 vulture pairs nesting at the year 2000 (70 in the Golan heights), we are down to only 45 pairs at 2017 (only two in the Golan). This, together with high average annual mortality (at least 12 per year) suggest we are approaching the extinction of this species in Israel and probably also through the Middle East.
There are numerous anthropogenic factors causing this collapse of the GV's population in Israel and worldwide. Among them: poisoning, loss of food or habitat and food resources, electrocution, trauma from electric posts and wires, wind turbines, gun shot, and more.... Poisoning are often caused by veterinary drugs and illegal use of pesticides by farmers, as a mean to control predators or as a secondary lead poisoning. Thus it might be useful to know how they die...
How do we know what injured or killed a vulture?As part of the INPA surveillance of the GV population vultures are fitted with GPS transmitters. These help us know about their movement, their ecology and behavior. Moreover, when the a tagged bird shows little or no movement it is often is a sign that the vulture is ill or dead (assuming the tag has not fallen off the animal).
These vultures are searched for by the INPA rangers and brought to the Israeli wildlife hospital if injured. These animals are checked for physical injuries, bloodwork and swabs are taken for biochemistry, pathogens and toxin levels. After hospitalization and treatment if the animal is fit to be released its movement will continue to be monitored.
If the vulture is found dead a full necropsy will be performed to find the cause of death. The animal will be checked for pathogens and toxins.
So how can this help conservation of the vultures?
If we can understand how different threats affect the vulture’s movement, we will be able to detect injured vultures early and protect the rest of the vulture population.
Individual behavior can also affect the risk of exposure to pathogens (for example a more social vulture will be in contact with more vultures and be in greater risk to be infected by pathogens and a bigger risk of spreading them). On the other hand, a more solitary bird might have a different risk of exposure to poisoning than others.
Hopefully, having a better understanding of the connection between movement behavior and epidemiology will help us come up with strategies to reduce the threats to this endangered species.