Foraging ecology and space use of breeding Flammulated Owls (Psiloscops flammeolus) in northern Utah

Abstract

Flammulated Owls (Psiloscops flammeolus) are small, insectivores that are of conservation concern due to climate change, shifts in habitat, and fluctuating resources. Flammulated Owls in northern Utah tend to occupy different habitats compared to other populations in the west. Primarily, we evaluated space use by male owls during the nesting period to better understand how habitat characteristics influence foraging behavior. We deployed GPS trackers on males to obtain location data. We documented habitat characteristics at owl locations to generate detailed information regarding habitat characteristics and quality as measured by moth abundance over the breeding period. Analyses suggested that birds used patches with high herbaceous plant richness, diversity, and less canopy cover which supported nocturnal moth abundances. Additionally, we concluded that two study areas differed significantly for the woody richness. While evaluating the mean distances traveled from the nest to owl locations, we found tree density, herbaceous species richness, and nocturnal moth biomass may all predict movement patterns. Owl density maps were created to visualize space use. Home range size was predicted by canopy cover and woody species richness. These data provide valuable information on how to support and manage habitats for this unique owl species.