Seasonal and Sex-Biased Survival of Adult Interior Western Screech-Owls (Megascops kennicottii macfarlanei) in Southeast British Columbia

Abstract

In Canada and in British Columbia, the interior Western Screech-Owl (Megascops kennicottii macfarlanei) has been assessed as a species at risk primarily as a result of loss and degradation of low-elevation riparian habitat. Few data exist on population demographics of this subspecies. We analyzed annual survival of 19 radio-tagged adult owls from 2009 through 2013 using known-fate models. Time and sex dependence in annual survival rates were examined. The best approximating models suggested that female annual survival (28%) was lower than male survival (83%). Owl survival was lowest prior to incubation and during brood rearing, times when owls are most vocal. Mortality was attributed to avian predation and road mortality. Management practices to preserve habitat during the critical breeding period are encouraged in light of this research.