Grassland systems in South Africa are under severe threat and estimates place more than thirty percent of the biome as permanently transformed. The transformation has occurred primarily due to cultivation, forestry plantations, urbanisation and mining. Untransformed grassland tends to be highly fragmented and the threat of continued transformation is high due to the suitability of the biome for important economic activities.
Climate change models predict that as much as fifty-five percent of the remaining extent of grassland systems may be reduced in future.
The African Grass Owl, Tyto capensis, as its name implies, is a grassland specialist and with population estimates in South Africa of less than 5000.
This species has a listed conservation status of Vulnerable.
Preferred habitat includes patches of tall, rank grass, sedges or weeds. These dense patches of vegetation are utilised by the birds for roosting and nesting, often close to wetlands. The nests, located on the ground, are susceptible to predation, trampling by grazing animals and fires. The Grass Owl breeds in autumn and early winter (peaking March – April), when the grass cover is at its thickest, rainfall at its highest and rodent populations at their largest.
Incorrect burning practices, specifically the burning of veld at the incorrect time of the year when Grass Owls are breeding, lead to the failure of many nesting attempts. Overgrazing and trampling of remnant grassland patches may lead to low reproductive success as well as abandonment of territories.
The threat of birds being struck by motor vehicles has been exacerbated by the transportation of grain by trucks along the road networks of South Africa. Grain that falls from the trucks increases the densities of rodents along the road verges, which, in turn attracts owls that predate on them. Further threats that the species is heavily prone towards include disturbance and frequent visits to nests by humans hoping to view the species may lead to the abandonment of nests and young.
Grassland systems are not well represented in South Africa’s protected areas and the importance of private landowners in the management of rank grasslands and wetlands cannot be ignored. Correct burning cycles and grazing regimes will improve the breeding success of the species, but the rehabilitation and restoration of degraded habitat will prove crucial to increasing local populations and new ranges for birds to populate.
Populations of the Grass Owl are already believed to be decreasing in many of the most populated sections if the species’ range and the environmental threats facing grassland systems are unlikely to diminish in the foreseeable future. The Endangered Wildlife Trust Birds of Prey Working Group has developed a dedicated African Grass Owl task force to answer questions relating to the distribution, behaviour and conservation status of the species. Public awareness, conservation of remaining habitat, best practice in the agricultural landscape and a respect for the species over critical breeding periods will go a long way towards their protection.