I believe that the landscape would largely influence the foraging activity of vultures. Many landscape classes will favor the access to food, as the areas next to roads, urban areas, etc. Depending on the scale, climatic factors will also influence the activity of vultures. I think you need to define a question/hypothesis and a scale and then choose some abiotic variables relates do the landscape and climate to explain the distribution of these animals.
Habitat type for prey is what you are looking for. You could perhaps review literature for assessment and mapping of this habitat and measure fragmentation index for it to estimate potential foraging zones.