The Zambezi National Park Hyena Project
On the 4th of September, a female hyena, CH81, was collared with a VHF radio collar to launch ALERT’s Zambezi National Park Hyena Project, in partnership with the Zimbabwe Parks & Wildlife Management Authority and Lion Encounter.
This programme aims to study the population ecology of spotted hyena as well as their relationship with their key competitor; lions. This is the first such study carried out on spotted hyena in the area. The study will also identify key habitat elements of spotted hyenas (e.g. den sites) which are required to facilitate conservation, establish descriptions of their home range which include the size, position, habitat and density and also to provide an assessment of population dynamics such as mortality and survival.
CH81 is affectionately known by the research team as Rusa after two ladies that were part of the collaring process, which took place at the edge of an open grassland area, also known as the Chamabondo vlei, in the Southern section of the Zambezi National Park.
This is now the 4th week of monitoring this female and a den site has been identified. The communal den site is being used by hyenas of several age classes; to date we have observed CH81 along with 2 adults 4 sub-adults and 3 juveniles.
When Rusa was collared she was noticed to be lactating. She has since been seen suckling one of the cubs at this den, but as there are three cubs present they likely belong to more than one female. These 3 sub-adults and 3 juveniles spend most of their time alone at the den without any adult present to watch them, behaviour common of spotted hyenas. One of the sub-adults however is already spending time out with the adults foraging.
Spotted hyenas are the most common and abundant large mammal carnivore in many African ecosystems and the Zambezi hyena population is no exception. This in turn puts pressure on them to actively hunt as they do not have a reliable source of carcasses to scavenge on. They are however very efficient hunters and although not yet observed, obviously do hunt the widespread prey species found in the area. Nevertheless, several herds of zebra and sable of mixed age classes are often seen comfortably foraging around this den site, despite the risk of predation they face.
This den is also located in the middle of a grassland which, at the moment, has new shoots of grass that have come out after the seasonal fires had burnt the area a few months ago. This has attracted grazers that are utilizing the new grass and they presumably value acquiring nutritious forage over the threat from predators.
As a source of food, these hyenas also have lots of Kori Bustards (largest flying bird native to Africa) that also forage and like the good view that the short grass provides. Considering these birds do not nest and just lay their eggs on the ground, they are possibly a substantial source of food for the hyena.
The images below show where this hyena has been since we started following it.
Key: Zambezi National Park (black polygon), Communal den (white circles), Rusa sightings (green placemarks), Rusa strong signal but no sighting (yellow placemarks), Rusa collaring site (red cross), Chamabondo borehole 3 ( blue triangle).
Hayward (2006) found that the dietary niche breadth of the spotted hyena is similar to that of the lion, and the two species have a 58.6% actual prey species overlap and a 68.8% preferred prey species overlap. These results highlighted the flexible and unselective nature of spotted hyena predation and are probably a reason for the species’ success throughout its range, despite a large degree of dietary overlap with lions.
Large carnivores are iconic species, but because they naturally live at low densities they are at increased risk of extinction (Gittleman et al., 2001; Macdonald & Sillero-Zubiri, 2004). Spotted hyenas are classified as ‘least concern’ by the IUCN, but their population is decreasing across their range (Honer et al., 2013), including within protected areas, as is the lion population (Bauer et al., 2015). The relationship between these two carnivores is a complex balance of competition and facilitation, and therefore there is need of a better understanding of their effects on each other in order to make decisions about their conservation (Periquet et al, 2014). This study will also examine the spatio-temporal relationships between hyenas and lions at different scales and investigate how these relationships can influence the whole-ecosystem functioning through trophic cascades.
Monitoring of Rusa and the rest of Chamabondo clan is going to continue and will provide more information on the range and hopefully the diet of these spotted hyenas within the Zambezi National 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, the African Lion and Environmental Research Trust and Lion Encounter and is expected to last at least three years. At the end of the study management recommendations will be presented to ZPWMA.