Use of GPS to identify the grazing areas of hill sheep

Within flocks grazing land contaminated with radioactive fallout following the Chernobyl nuclear accident, certain sheep have comparatively high levels of radiocaesium. To understand why only certain sheep are affected, the precise grazing areas of these animals need to be identified. An animal behaviour and tracking system, that utilises the Global Positioning System (GPS), has been developed and was tested in upland West Cumbria, UK. Although there was evidence that hilly terrain did occasionally affect the function of the GPS receiver, this was for only 2.5% of the time in the worst case. The study clearly demonstrates that GPS can be used to track domestic sheep, and could be used to identify home ranges and the specific areas giving rise to contaminated animals. (C) 1997 Elsevier Science B.V.