Nest structure and breeding habitat characteristics of Barred Owls (Strix varia) in Manitoba, Canada

Abstract

Barred Owls were located through audio playback surveying searching in southern Manitoba. Sixty-one confirmed home ranges were located and nine nest sites were located. Mean diameter at breast height and cavity depth and width were determined to be limiting factors governing Barred Owl distribution. Barred Owl habitat use was examined at two scales: immediately around nest trees and within estimated breeding and non-breeding home ranges. Barred Owl breeding and non-breeding home ranges had significantly more hardwood and mixedwood than random plots. Barred Owl breeding season commenced in early March, egg laying in early April, hatching in early May, and fledging at the start of June. Mean and standard deviation of clutch size were 1.91 ± 0.83. Barred Owl diet was determined to be generalist in nature. Dietary breadth was calculated, using Simpson’s formula for measurement of diversity in a sample, of D = 0.1525.