Date of Award
Master of Science (MS)
Division of Agriculture (SAFES)
Dr. Kyle Barrett, Committee Chair
Dr. Robert F. Baldwin
Dr. Catherine M. Bodinof Jachowski
Dr. Patrick Jodice
Despite extensive accounts in the literature describing Barred Owls (Strix varia) as obligate forest-interior species that are sensitive to development, Barred Owls have increasingly been found in urbanized landscapes. Due to the limited number of studies on Barred Owls within the context of development, our understanding of the processes that facilitate Barred Owls within anthropogenic landscapes is limited. In the Piedmont region of the southeastern United States, South Carolina, the presence of Barred Owls in suburbs and small-town centers precipitated our research team to examine which habitat features facilitate their occurrence near development.
We conducted surveys using callbacks and autonomous recording units within a 300 km2 region centered around Clemson, South Carolina. We used detection/nondetection data to model the influence of habitat features on Barred Owl occupancy along a development gradient. Tree height was the best predictor of Barred Owl occupancy, regardless of forest coverage. We did not find Barred Owl occupancy to decline with increasing impervious surface density.
To further investigate habitat selection at a finer scale, we deployed GPS transmitters on 20 breeding Barred Owls in our region during a single breeding season. We selected territories containing a variety of development density and habitat types to examine predictors of home range size and habitat selection along an urban-rural gradient. We related nocturnal (foraging) locations to habitat features using resource selection functions (RSFs). We explored differential use along a development gradient by modeling interactions between habitat parameters and measures of development in the home range. After accounting for variation attributable to sex, we found that Barred Owl home ranges expanded significantly in size with increasing forest fragmentation in the landscape. Tree height was one of the most important habitat predictors of foraging selection among the variables we evaluated, thus mature urban canopy could be the key to Barred Owl presence in developed landscapes. Barred Owls exhibited differential use based on development in the home range; owls within zones of higher fragmentation had stronger selection for anthropogenic features, such as roads and forest edges. Although our findings confirm that certain habitat features, such as tall canopy, are integral to supporting a breeding population of Barred Owls within development, our results also demonstrate the plasticity of a forest predator previously described as sensitive to urbanization. The presence of Barred Owls in developed landscapes suggests that retaining key habitat features can promote multi-trophic communities even when other aspects of the habitat are highly altered.
Clement, Marion Alice, "Habitat Features and Behavioral Plasticity Promote Barred Owl Presence in Developed Landscapes" (2020). All Theses. 3364.