During the month of October, we have been tracking the two GPS collared spotted hyenas in Zambezi National Park for the purpose of understanding their ecology, habitat preferences and range. These two hyenas, H153 and H154, differ in that one ranges far from human habitation, whilst the other one stays closer to Victoria Falls town.
Using the downloads from the GPS collars, we have begun to assess the home range and utilisation distribution (UD) for both hyenas. To do this we used specialised software to delineate a minimum convex polygon, which is the boundary of where they have been since they were collared, Figure 1 (below).
H153, the hyena which was collared far from human habitation, has the biggest range area of 60 826 acres, whilst H154 has so far been ranging in an area of 48 482 acres.
We also calculated the 95% Kernel home range and 50% core range. The 95% home range corresponds to the area in which the probability of finding the animal is equal to 0.95. The 50% core range is the area with a 0.50 relocation probability. The core range is always smaller than the home range.
Figure 2 (below) shows the home range (95% - 17 980 acres) and core range (50% - 1 492 acres) for H154. The current home range for H154 shows that it spends significant amount of time outside the Park in/near Victoria Falls town, mostly around residential areas and the rubbish dump. This also shows the areas that this hyena goes in search for food. However the core range is localised within a Teak vegetation type, which is possibly an area it spends most of its time during the day (e.g. den site).
Figure 3 (below) shows the home range (95% - 43 985 acres) and core range (50% - 6 364 acres) for H153. The current home range shows that it also spends significant amount of time outside the Park. However, H153 seems not to come into contact with human habitation, but wanders around a forestry area and other safari areas that surround the south-western part of the Zambezi National Park. Nevertheless, the core range (50%) of H153 is within the boundaries of the Zambezi National Park.
These two hyenas have a slight home range overlap. H154 seems to utilise only two waterholes within its home range, whilst H153 has three known waterholes found within the Zambezi National Park, not knowing some other ones that are found within the neighbouring safari areas and forestry area.
These differences in home range sizes are possibly a function of reproductive state, social rank and local prey abundance. H154 is a male who seems to have easy access to forage and hence does not need to travel far, whereas H153, a female, is ranging in a larger area which could be a sign of prey scarcity and/or it being a low ranking female with no den-dwelling cubs resulting in it ranging in areas outside the Park.
About the Zambezi National Park Hyena Project
Large mammal carnivores play an important role in maintaining a balance between the ungulate population and the environment. However, when carnivore numbers increase, certain age classes of the ungulate population can be negatively affected. Spotted hyena, contrary to popular thought, do hunt extensively and predate mainly on the juvenile age class, although they will also take down adult animals. Spotted hyena are the most common and abundant large mammal predator in many African ecosystems. In Zambezi National Park and surrounding areas it has been reported that there is little recruitment into the juvenile age class in the large ungulate population and it is hypothesized that this is due to a large spotted hyena population. In addition, reports have been received that hyena are significantly involved in livestock predation in nearby human-populated areas. To date no studies have been carried out on spotted hyena in the area and this study will look at the population dynamics of this species in the areas mentioned to obtain population size, population dynamics, recruitment, home-range, prey preference and interaction with livestock. The interaction between lions and hyena will also be studied as these two species are major competitors and are known to limit population growth within their populations. This study will be undertaken as a joint project between the Parks and Wildlife Management Authority and the African Lion and Environmental Research Trust and is expected to last at least three years. At the end of the study management recommendations will be presented to ZPWMA.