Breeding biology of the Barn Owl (Tyto alba) in the Lower Mainland of British Columbia

Abstract

Breeding of the Barn Owl was studied from 1990-1992 in the Lower Mainland of British Columbia, the northern limit of the species' North American range. Over 3 years, mean clutch size was 6.5 ± 3.5, mean brood size at time of banding was 3.3 ± 2.0, and mean number of nestlings fledged was 2.6 ± 2.1. Clutch size ranged from 2 to 18 eggs. There were no significant differences in fledging success rates between years. Severe weather in 1991 resulted in high Barn Owl mortality. If the number of nestlings banded per year is used as an index of productivity and the number of barn owl carcasses reported per year is used as an index of mortality, the year of 1991 has both the highest mortality and the lowest productivity of the 3 years. The use of man-made sites by Barn Owls for roosting and nesting provides increased thermal cover and security from predators which may be vital for the species at the northern limit of its distribution.

Parent Publication

• Biology and conservation of owls of the Northern Hemisphere: 2nd International symposium

Citation

Andrusiak, Lorraine A.; Cheng, K. M. 1997. Breeding biology of the Barn Owl (Tyto alba) in the Lower Mainland of British Columbia. In: Duncan, James R.; Johnson, David H.; Nicholls, Thomas H., eds. Biology and conservation of owls of the Northern Hemisphere: 2nd International symposium. Gen. Tech. Rep. NC-190. St. Paul, MN: U.S. Dept. of Agriculture, Forest Service, North Central Forest Experiment Station. 38-46.