Effects of Filter Strips on Habitat Use and Home Range of Northern Bobwhites on Alligator River National Wildlife Refuge

Lack of breeding habitat for northern bobwhites (Colinus virginianus) on agricultural landscapes is a factor that limits populations. Therefore, we examined how the addition of filter strips around crop fields and along crop field drainage ditches impacted northern bobwhites. Our study focused on habitat use, home range and brood-rearing range of bobwhites, from April through September I 993-94. Two farms on Alligator River National Wildlife Refuge were sub-divided into filter strip (FS) and non-filter strip (NFS) sections. More bobwhites were found on FS sections than on NFS sections based on flush counts (4.3x more on FS areas: P = 0.02). We used log-linear analysis to examine the distribution of telemetry locations (n = 1796) of radio-marked bobwhites (n = 218) across 5, 4.6m bands parallel to drainage ditches. Bobwhite locations were skewed towards ditches, particularly on FS sections before soybeans matured to a size that was sufficient to provide canopy cover for bobwhites. Bobwhites captured on FS sections had significantly smaller breeding season ranges than those captured on NFS sections (P = 0.001). Adult and sub-adult breeding season (May-Aug) ranges (n = 23) averaged 32 ha (SE = 26) and 182 ha (SE = 41) on FS and NFS sections, respectively. Brood ranges to 14 days (n = 9) ranged from 0.8 ha to 2.2 ha depending on habitat and calculation method. Presence of filter strips shifted habitat use patterns, especially during spring and early summer, and improved crop fields as habitat for breeding bobwhites