Barn owl pellets: A useful tool for monitoring small mammal communities?

Monthly fluctuations in the diet of barn owl Tyto alba were compared to prey availability in a typical South African dry sandy highveld grassland over a 12 month period. Mice, shrews, bats, birds and insects were all major prey items, and their contribution in pellets fluctuated significantly over months. Barn owl proved to be very efficient samplers of the small mammal prey group: not only was the owl more successful than museum personnel in sampling the variety of species present during a specific time of year, but peaks in prey utilization were also more characteristic of actual fluctuations than that found by traps. Owl pellet analysis is a valuable asset during small mammal monitoring studies, and is especially useful for sampling small mammal indicator species during environmental impact assessments. However, owl pellet analysis should never be seen as an alternative for small mammal trapping when small mammal community structure is the focus of study.