Avian translocations and disease; implications for New Zealand conservation

Abstract

There is little published information on the pathogens present in New Zealand passerines. We report here on a preliminary survey of selected pathogens and haematology profiles for seven species in the Auckland region. Avian translocations are commonly used for the recovery of threatened species. Translocations may increase the risk of spreading disease to immunologically naïve populations. It is therefore important to take every opportuntty to gather baseline disease data and test hypotheses associated with disease. Blood, cloacal and faecal samples were collected from Fernbird Bowdleria punctata, Tui Prosthemadera novaeseelandiae, Bellbird Anthornis melanura, Tomtit Petroica macrocephala, New Zealand Robin Petroica australis, Whitehead Mohua albicilla and Starling Sturnus vulgaris during four translocations to and from Tiritiri Matangi Island. Birds (n = 137) were also examined for external lesions typical of avian pox. Blood samples (n = 40) were screened by microscopy for Plasmodium spp., Atoxoplasma spp. and other blood parasites and a differential white blood cell count was made. Cloacal swabs (n = 38) were cultured for Yersinia spp., Salmonella spp. and Campyobaeter spp. Faecal samples were screened for coccidia spp. (n = 28). An unidentified coccidian sp. and a Haemoproteus sp. were detected in one Fembird and one robin respectively. No other organisms with the potential to cause disease were detected. Despite the effort required to complete disease screening, we argue that disease samples and baseline haematology normal values should be collected at an opportunities. We make recommendations for future disease screening, and discuss the importance and potential significance of disease to the conservation of New Zealand's biodiversity.