Influence of Relatedness and Nest Site Characteristics on Return Rates in Burrowing Owls

Burrowing Owls (Athene cunicularia) were listed as an endangered species under the Wildlife Act in British Columbia (BC) in 1996 and have been extirpated from the province since 1980. To counteract their declining numbers, several captive breeding and release facilities set up across BC are attempting to re-establish sustainable breeding populations. However, these efforts have met with limited success due to low return rates of the birds released. The goal behind this research is to discover whether or not historical pedigree data combined with nest site characteristics can predict and improve owl return rates and reproductive success. The pedigree records enable us to examine not only relatedness, but also general trends over time, for example, bird weight and fecundity among owl lineages. The study also encompasses an investigation of various burrow characteristics, including height, depth and entrance direction - this is then compared with known occupancy and return rates to ensure optimum placement and construction of burrows. Ideally, this research will assist understanding which birds are returning to BC, and to which location, so that resident Burrowing Owl populations can be restored in BC