Prey Delivery Inside an Artificial Nest Box and Burrows Used by Nesting Burrowing Owls in el Paso, Texas

Abstract

ABSTRACT Determining the diet of species that nest underground, such as the Burrowing Owl (Athene cunicularia), is challenging. Prey information for Burrowing Owls is often limited to prey remains at nest sites and in owl pellets, images collected from above-ground trail cameras, or direct observations of prey acquisition and delivery. To document prey use and nesting behaviors, we equipped an artificial nest box and burrows at Rio Bosque Wetlands Park in El Paso, Texas, with a digital video recorder and three underground infrared cameras. Herein we document the types and frequencies of prey items delivered inside the nest box during the 2019 nesting season, as reflected in videos and images collected continuously from 1 April to 5 July. We reviewed 23,039 video files and documented 580 prey deliveries. We identified 463 (80%) of the delivered prey items to class and 237 items (41%) to family. Invertebrates made up 75% and vertebrates 25% of the identifiable prey items by frequency. Most (55%) of the invertebrates were insects, especially in the orders Orthoptera and Blattodea; scorpions (Scorpiones) were the second most common group (2% of all items). Vertebrate prey were delivered less often and mostly consisted of rodents (14% of all prey items), especially heteromyids, followed by squamate reptiles (6%). Results from this project will aid in conservation and management of this species.