Movements and habitat use of feral house cats Felis catus, stoats Mustela erminea and ferrets Mustela furo, in grassland surrounding Yellow-eyed penguin Megadyptes antipodes breeding areas in spring

This paper reports a radio-tracking study of movements of feral house cats Felis catus, stoats Mustela erminea and fer refs Mustela furo during spring around Yellow-eyed penguin Megadyptes antipodes (hoiho) breeding areas in coastal Otago, South Island, New Zealand. Grassland around these breeding areas has been retired from grazing by domestic stock to establish 'vegetation buffers' intended to reduce predation of hoiho chicks by introduced mammalian predators. The 'vegetation buffers' did not exclude or deter predators. In fact, the opposite effect was evident: 'vegetation buffers' attracted cats, stoats and may have attracted ferrets to the area. Attraction of predators to 'vegetation buffers' could increase encounter rates between predators and penguin chicks, especially by stoats, which are difficult to trap. 'Vegetation buffers may therefore increase predation rates, but this is unmeasured. This research highlights the need for rigorous testing of proposed biological controls such as habitat modifications before widely implementing them as ways of protecting native wildlife. (C) 1998 Elsevier Science Ltd.