The Barn Owl Monitoring Programme: Establishing a Protocol to Assess Temporal and Spatial Variation in Productivity at a National Scale

Abstract

Once regarded as Britain's most abundant owl species, Barn Owl Tyto alba numbers declined substantially from 1850 to 1950. While more recent surveys suggest that numbers may now have stabilized, breeding range declines and the species' unfavourable European conservation status have resulted in its inclusion on the Birds of Conservation Concern Amber List. As existing schemes were not suited to monitoring the abundance of low density, nocturnal species, the Barn Owl Monitoring Programme (BOMP) was established by the British Trust for Ornithology in 2000, assisted by the Wildlife Conservation Partnership. Under BOMP methodology, approximately 600 potential breeding sites (c. 10% of the national population) located throughout the British Isles are visited by volunteer observers each year who record owl occupancy and productivity. These data are used to assess long-term trends, and the results from the first six years of data collection (2000–05) are presented in this paper. As expected, given the short time-...