Presence, Habitat Use, and Prey Selection of Champlain ValleyOwls, New York

Abstract

In this study we examined species-specific owl occupancy and detection, habitat usage and distance to landscape features, as well as food availability of owl species encountered in Clinton County, New York. Through broadcasting owl vocalizations, we were able to identify and determine owl habitat usage using an inexpensive, non-invasive technique. Lunar cycles were also assessed to determine when the owls were most active. Lastly, we hand collected owl pellets to determine what the owls may be eating in Northern New York. Program PRESCENCE was used to assess presence and occupancy across sites. We encountered barred owls (Strix varia) and great horned owls (Bubo virginianus) occurring and co-occurring at 100% of our sites. Detection probabilities for barred owls were 29% and only 4% for great horned owls. Through the use of ArcGIS is was determined that agricultural land-use and forests were the dominate habitat types surrounding the broadcasting sites. Roads and wetlands were reoccurring habitat across sites. We observed that owls were more vocal on nights of high lunar illumination. Through the dissection of owl pellets we concluded that small mammals such as grey squirrels and mice (Peromyscus spp.) were selected prey of a great horned owl. Understanding owl habitat-use patterns is important for habitat conservation purposes in the future as habitat fragmentation and habitat destruction become more persistent across the landscape. We hope to expand our research to other location including residential areas and urban parks to create a better understanding of owl habitat usage in Clinton County.