Dr Rob Little (PFIAO)
Alex Atkins (CB MSc student, PFIAO)
Beth Mackay (BSc Hons, UCT)
Jess Sutton (Scholar, Reddam House)
Frances Morling (Research Assistant)
Managing Egyptian Geese on golf courses
Human-wildlife conflict is increasing in the modern world where human populations are usurping indigenous wildlife habitats. South African golf courses experience similar problems with Egyptian Geese Alopochen aegyptiaca as are experienced with Canada Geese Branta canadensis on golf courses in North America.
Although indigenous to the Western Cape, Egyptian Geese numbers have recently increased. Habitat choice is influenced by the presence of predators and visual obstructions which decrease perceived safety levels. Preferred habitats are at water bodies, particularly man-made dams, with open shorelines and unhindered view of the surrounding area. Predation risk is also reduced by adjusting group size, with less per capita vigilance required in large groups. Urbanization may further alter perceived predation risk, since natural predators are often scarce and open areas with open water are plentiful, thus geese experience safer conditions than in natural landscapes. South African golf courses are attractive to geese because large, irrigated grazing lawns are interspersed with artificial water bodies and predators are largely absent. The accumulation of goose faeces pollutes the greens and fairways which diminishes the aesthetic and recreational value of the area.
Assessing the issue
To assess perceptions towards Egyptian Geese, Jess Sutton (Grade 12 scholar) surveyed the residents and members of the Steenberg Golf Estate, Cape Town. Of 548 questionnaires sent to residents and non-resident golfing members, most respondents (84%) considered that geese were a problem on the estate. However, only 57% of non-golfers perceived the geese as a problem, suggesting that the issue is more problem specific to the golfers. Most golfers (87%) felt that the goose population requires active management. The majority (86% of all respondents) considered that the goose population should be reduced by 50% or more.
Traditional goose control methods can be non-lethal or lethal. Non-lethal methods have included visual and audio displays, including scarecrows, fake predators, flashing lights, bird alarms and fireworks. However, most have had little success because the geese soon become habituated to their presence. The use of trained herding dogs has proved to be more successful. However, trained dogs are expensive and have high maintenance costs. Relocation of geese to new habitats is also expensive and there are concerns that the geese will return to the site of capture, or will begin novel conflicts in other areas.
Lethal measures include egg addling and culling. However, the high mobility of the geese renders both relatively ineffective at the level of local populations. Furthermore, when geese abandon unsuccessful nests, they typically make a new nest and thus a repeated clutch. Shooting geese in residential areas is considered unethical, and while lethal methods are more cost-effective than non-lethal options, they are often deemed socially unacceptable. In general, the failure of most control methods is due to their short term efficacy, high cost or ethical unacceptability, with no long-term solutions to the problem. While it is not necessary to eliminate geese from a property, managing their numbers at a level where they are tolerated by managers and golfers may be important.
Dealing with the issue
Following the perceptions survey, Beth Mackay (BSc Hons student) investigated the vigilance behaviour of Egyptian Geese at Steenberg and the attributes of various habitat features at ten golf courses in the Western Cape to understand what makes them attractive to the geese. Predation risk is reduced by being vigilant, which includes visual scanning to increase the probability of detecting a predator. Vigilance is thus higher in areas of increased predation risk and can act as a surrogate for the perceived safety of the geese in their surroundings. Beth found that although goose vigilance levels were inversely related to group size, vigilance levels were less in ‘hotspots’ than in areas less favoured, ‘non-hotspots’, independent of group size, confirming that certain habitat characteristics cause the geese to feel secure. Hotspots, where geese aggregate on a daily basis, and thus where goose faeces needed most frequently to be removed, were defined by two predictable habitat features. The most important of these was the distance to water, with hotspots most often being areas <100m from the nearest water body. The other important correlate of goose hotspots was the size of open patches of lawn, with patches >1.5ha in size most favoured.
Golf course management should therefore shift from focusing on the birds themselves to reducing the number of favoured sites or to have favoured sites located in the non-playing areas of the course. Whilst water bodies adjacent to large, open lawns could be avoided when designing a golf course, poorly sited ponds on existing courses should be modified with physical barriers to restrict access to the water. These barriers can be fences along the edge of the water, or a wire grid placed over the water surface. The most inexpensive and attractive method is to plant vegetation along the edge of the water which will interrupt their access to the water and decrease their ability to detect predators.
Considering that large patches of open lawn are attractive safety features for geese, tall grass and shrubs can also be planted around the fairways of existing golf courses which will reduce the openness, and hence the safety levels perceived by the geese. Designing golf courses and adjacent vegetation so that they are attractive to local bird species while simultaneously being less attractive to Egyptian Geese involves short-term costs with potential long-term benefits.
As an extension of the investigation of potential management practices during the second half of 2014, Alex Atkins (CB MSc student) assessed the effects and response of harassing Egyptian Geese on Rondebosch Golf Course with a Harris Hawk Parabuteo unicinctus. He measured both the response of the course population numbers and the vigilance levels before, during and after the harassment pressure from the raptor.
Thanks to the golf course managers for their assistance, the members of the Steenberg Golf Estate for participation in the perceptions survey, and to Rachel Colyn at NCC Environmental Services who helped with GIS mapping of the golf courses.
- The perceptions and habitat manipulation aspects of the research were published in Ostrich and in the Journal of Wildlife Management, during 2013 and 2014 respectively.
- Comprehensive articles on the research have appeared in African Birdlife, Environment and the national Golf Club Management magazine during 2014.
- A management plan, a research presentation, and implementation advice have been given in collaboration with NCC Environmental Services to the Steenberg Golf Estate.
- Research findings and management best practice guidelines for golf courses have been conveyed to the Western Cape golf course managers committee and to CapeNature.