New Zealand Journal of Ecology (2008) 32(2): 214- 218

Diet of ship rats following a mast event in beech (Nothofagus spp.) forest

Short Communication
Shirley McQueen 1*
Barry Lawrence 2
  1. Otago Conservancy, Department of Conservation, PO Box 5244, Dunedin, New Zealand
  2. Wakatipu Area, Department of Conservation, PO Box 811, Queenstown, New Zealand
*  Corresponding author

Diet of 98 ship rats (Rattus rattus) was investigated by examination of stomach contents. Rats were trapped (as bycatch in stoat traps) from June to December 2006, in the Dart Valley near Lake Wakatipu, New Zealand, after a Nothofagus beech mast. Plant material was found in 43% of all stomachs, invertebrate fragments in 67%, feathers in 8%, hairs in 46% and skin with hairs attached in 12%, and animal (vertebrate and invertebrate) tissue in 76%. Hair samples examined by scanning electron microscopy were from mice, and rat and/or mouse DNA was found in all (10) samples subjected to DNA extraction. Mice may be an important food resource for rats following beech masts, when mouse population densities are high. Presence of feathers indicates predation of roosting or nesting birds, or scavenging. Consumption of beech seed beyond the time of germination may be due to caching of seed.