Fat content and morphometric data in barred owls (Strix varia) in the Pacific Northwest

Body condition indices and related metrics can help assess habitat quality and other ecological processes, and ideally these metrics are based on measures of lipids directly extracted from the species of interest. In recent decades, barred owls (Strix varia) have become a species of conservation concern as they invaded older forests of the U.S. Pacific Northwest, and caused population declines of the closely related and federally threatened northern spotted owl (S. occidentalis caurina). A simple and effective measure of barred owl body condition could help to understand how habitat quality varies within their new range, which in turn can inform their management and other aspects of their ecology. Using 77 barred owl carcasses collected during experimental removals in Washington and Oregon, USA, we measured the amount of lipid in each specimen with proximate body composition analysis.