Patterns of Occupancy, Productivity, Site Tenure, and Recruitment in a Population of Burrowing Owls in Idaho, USA

Western Burrowing Owls (Athene cunicularia hypugaea) are ground-dwelling owls of western and central North America that breed in abandoned mammal burrows. The species is of conservation concern throughout portions of its range, so understanding population dynamics, fitness outcomes, and attributes of the most productive breeding sites are important for management, conservation, and the understanding of life history. Between 1997-2021, a mark-recapture approach was used to monitor a nesting population of Burrowing Owls making use of artificial burrows in the Morley Nelson Snake River Birds of Prey National Conservation Area, ID, USA. The study area is predominantly shrub steppe and disturbed grasslands but has a small percentage of irrigated agriculture, and Burrowing Owls breed in both settings. Using data from this 25-yr timespan, our objective was to assess attributes of the most productive and the most frequently occupied artificial burrow sites. We also were interested in deciphering patterns of tenure and turnover of individuals among sites, as well as locations of sites that were sources of recruits to the breeding population. We analyzed data from approximately 4900 individually marked owls from approximately 950 nests, including 800 nesting adult females, 400 adult males, and almost 4000 nestlings. We identified sites with the greatest occupancy, productivity, and number of recruits, assessed land cover characteristics at each, and analyzed relationships with occupancy, productivity, tenure, and recruitment. Finally, we evaluated if patterns were similar between agricultural areas and grasslands/shrublands