The urban landscape is understudied compared to less developed ecosystems, despite providing suitable habitat for wildlife, including some species of grassland birds. Loggerhead Shrikes (Lanius ludovicianus) are predatory songbirds that frequent grasslands and have been observed using grassy areas in developed and more natural landscapes, yet remain largely unstudied in developed landscapes. We investigated the effects of development, measured as impervious surface percentage, on Loggerhead Shrike occurrence in urban areas in South Carolina, U.S.A, and also tracked canopy cover (%), highway density (m/ha), non-highway road density (m/ha), total road density (m/ha), and powerline density (m/ha). The first author searched 300 2.25-ha sites in Charleston, Florence, Georgetown, and Horry counties for shrikes along a gradient from low to high impervious surface. All predictor variables were measured within every 2.25-ha survey site and also for a 20.25-ha “neighborhood” surrounding and including each survey site. Impervious surface and canopy cover were also measured within a 1-km circular buffer around each survey site. We used generalized linear models to identify factors associated with Loggerhead Shrike occurrence. In total, we detected Loggerhead Shrikes at 31 sites. Shrikes occurred at 2.25 ha sites with a wide range of impervious surface, ranging from 6.9 to 84.6%, with an average of 37.6% (SD = 26.2). Habitat variables at larger spatial scales (20.25 ha and 1 km circle) did not explain occupancy, but Loggerhead Shrike occurrence had weak negative relationships with impervious surface and highway density at the 2.25-ha scale. Highway density ranged from 0 to 148.1 m/ha at occupied sites, with a median of 0 m/ha. Despite its classification as a grassland bird, this study shows that Loggerhead Shrikes can use developed areas, including high-intensity development.
This article was published Open Access through the CCU Libraries Open Access Publishing Fund. The article was first published in the journal Urban Naturalist: https://www.eaglehill.us/URNAonline2/access-pages/060-Hill-accesspage.shtml
Krauser, M.A., & Hill, C.E. (2023). Loggerhead Shrike Occurrence Along Urban Gradients in South Carolina’s Coastal Plain. Urban Naturalist, 10(60), 1-14. https://www.eaglehill.us/URNAonline2/access-pages/060-Hill-accesspage.shtml. Available at https://digitalcommons.coastal.edu/biology/5/.