ECOLOGICAL DATA ON MICROMAMMALS COLLECTED BY BARN OWLS TYTO ALBA IN THE WEST COAST NATIONAL PARK, SOUTH AFRICA

ABSTRACT

Barn owls Tyto alba catch large numbers of micromammals and incidentally accumulate information concerning their prey. Here an outline is given of the contribution of barn owls to micro-distributional studies at five closely situated roosts in the West Coast National Park, southwestern South Africa. Seasonal variation in proportions of species and a positive correlation between mean mass of individual in monthly samples and rainfall at Geelbek B reflect the influence of rainfall on vegetation cover. Strong, but possibly spurious, correlations exist between various climatic factors and proportions of young in the vlei rat Otomys irroratus population at different times of the year. High incidences of co-occurrences of different species in owl pellets suggest possible co-habitation of the species concerned while co-occurrences of adult and perinatal O. irroratus provide reproductive information.