Habitat use by the critically endangered Blue Swallow in KwaZulu-Natal, South Africa

Abstract

Background: Habitat loss and fragmentation continue to threaten the survival of many species. One such species is the Blue Swallow Hirundo atrocaerulea, a critically endangered grassland specialist bird species endemic to sub-Saharan Africa. Objectives: Past research has shown a serious decline in range and abundance of this species, predominantly because of habitat transformation and fragmentation. Method: The influence of land cover on Blue Swallow habitat and foraging home range, in both natural and transformed habitats, was investigated by radio tracking adult birds. Results: Results showed that tracked birds spent over 80% of their forage time over grasslands and wetland habitats, and preferentially used these ecotones as forage zones. This is likely owing to an increase in insect mass and abundance in these habitats and ecotones. There was reduced selection and avoidance of transformed habitats such as agricultural land, and this is a concern as transformed land comprised 71% of the home range with only 29% of grassland and wetland mosaic remaining for the Blue Swallows to breed and forage in, highlighting the importance of ecotones as a key habitat requirement. The results indicate that management plans for the conservation of Blue Swallows must consider protecting and conserving natural habitats and maintaining mosaic of grassland and wetland components to maximise ecotones within conserved areas. Conclusion: To this end, the stewardship programme spearheaded by local conservation agencies, which aims to formally conserve privately owned patches of untransformed grassland and other natural habitats, may have a strong impact on the long-term persistence of Blue Swallow populations.

Keywords

• critically endangered
• natural land
• transformed land
• radio-tracking
• blue swallow
• foraging