Predator Research

Forest and Bird, Issue 293, 1 August 1999, Page 40

Predator Research

‘Video photography identifies the main predators at birds’ nests as cats, ferrets and hedgehogs. Stoats, a hawk and a magpie also preyed upon chicks and eggs, says project scientist Mark Sanders. Video cameras set up at nest sites provide indisputable proof of the impact predators have on nesting birds. Little is known, however, of the survival rate of mobile chicks that leave the nest. Using radio-transmitters on blackfronted tern chicks and juveniles, and banded dotterel juveniles, PhD student Rachel Keedwell is measuring chick and juvenile mortality to establish population models. Banded dotterel chicks are too small for transmitters, so a muzzled tracker dog will be used to locate them next season. More than 1000 hedgehogs were caught in a trapping campaign which was undertaken in response to the illegal introduction of rabbit haemorrhagic disease (RHD, formerly known as RCD). Videos also identified them as important predators. Over two summers hedgehogs were tracked by research student Kirsten Moss, who found they ate a wide range of insects. However their guts also contained feathers, egg shells and lizards. She also discovered that they have large home ranges, but mostly use a core area of about eight hectares. This is important information for designing hedgehog-control operations. Several other predator research projects are underway in the upper Waitaki, by Landcare Research, university students and DoC. A regular research meeting run by the project brings these parties together to discuss methods, findings and directions, and helps to avoid unwanted overlaps between experiments.