Grassland bird populations are experiencing major declines due to habitat degradation, pesticide use, and fire suppression throughout North America. Large-scale grassland restoration efforts to improve and provide suitable habitat are ongoing, but there is little data on productivity of birds breeding in restored habitats, nor on the impact of specific vegetation characteristics on reproductive success. Since 2005, agriculture fields at Panola Mountain State Park in central Georgia have been undergoing restoration to warm-season grasslands; however, until now, data on nest success or productivity was lacking. The goals of this project were to: (1) quantify reproductive success and (2) determine which vegetation characteristics were associated with successful nests. From March-August 2019, we monitored all active nests, recorded nest outcome, and measured several vegetation characteristics. We used Akaike’s Information Criterion (AICc) to determine which variables were most strongly associated with success. We found 52 nests of 11 species, with an overall success rate of 34.62%. Seventeen nests were cup nests, 35.29% of which were successful. The most common cause of failure for all nests was predation (91.18%). Nest type, plant height, plant height above the nest, and distance to water were most strongly associated with nest success overall; nest success was higher for nests in taller grasses with more grass above the nest, and those located further from water edges. All of these factors are linked with predation risk because they provide more concealment and/or are farther from areas where predators concentrate. We recommend that prescribed fires occur either in the winter or early enough in the spring so grasses can grow to appropriate heights and, when possible, that managers create natural buffers around abrupt water edges near nesting areas to ensure high quality, productive habitat for grassland birds.
Biological and Environmental Sciences
Allen, K., & Stumpf, K. J. (2021). Avian Reproductive Success is Associated with Multiple Vegetation Characteristics at an Active Grassland Restoration Site in Central Georgia. Georgia Journal of Sciences, 79(2).