The impact of human disturbance on the breeding success of nightjar Caprimulgus europaeus on heathlands in south Dorset, England.
Abstract
The effects on birds of human disturbance through recreation is an issue of conservation concern. With the passage of the Countryside and Rights of Way Act (2000) access patterns to heathland sites are likely to change. Yeat, very few studies have been published on the effects of access on heathland bird species. The nightjar is one of the key breeding species associated with lowland heathland in the British Isles. The breeding success of nightjars was compared on several sites in Dorset with varying levels of public access. Sites with no public access showed significantly higher breeding success than sites with open access. On sites with public access, territory centres and nest sites occurred considerably further away from urban development. In addition, nests that did succeed were located significantly further away from paths. The probability of nest survival was 12%. The key cause of nest loss was predation (60% of all nests failed, 93% due to predation). The evidence from nest remains, post predation, suggested that 63% of failed nests were predated by corvids. The results therefore suggest that predation and disturbance may bel inked, the possible mechanism being that birds nesting close to paths are flushed from the nestm ore often, betraying the nest site to predators. A necdotal evidence suggests that dogs off leads may be a particular cause for concern. The results have been presented with recommendations for site management and further work.