Distribution, abundance and habitat selection of northern pygmy and barred owls along the eastern slopes of the Alberta Rocky mountains

Abstract

Surveys for northern pygmy (NPOW) and barred (BAOW) owls were conducted to determine distribution, abundance and habitat selection along Alberta's eastern slopes. The effect of environmental conditions on owl response rates was examined and density estimates were produced using an analytical method that models variation in species detectability (distance sampling). Both species were widely distributed and occurred at low densities throughout the study area (NPOW: D=0.048 birds/km2, CVb=55.8, BAOW: D=0.025 birds/km2, CVb=30. 7). Stepwise logistic and autologistic regression were used to develop predictive models for each species. Autologistic models accounted for observed spatial dependencies. All models considered biophysical variable selection at two spatial scales, minimum and maximum home range. Habitat selection models will enable managers to set and reach habitat goals by quantifying species habitat requirements and determining predicted habitat availability based on management actions.