Assessing occurrence and effects of neonicotinoid pesticides on Loggerhead Shrike body condition, immunocompetence, survival, and reproduction
September 2019 - June 2023
- Brett DeGregorio, Co-Principal Investigator
- Than Boves, Co-Principal Investigator
- University of Arkansas Graduate School
- Arkansas Game and Fish Commission: State Wildlife Grant
The Loggerhead Shrike is a grassland associated avian species that is one of the fastest declining passerines in Arkansas and North America. Despite the dramatic decline, there is no clear censensus for why these populations continue to trend down so precipitously. One hypothesis that has yet to be evaluated is the influence of agricultural chemicals on the health and reproductive behavior of the Loggerhead Shrike. To improve our ability to conserve this Species of Greatest Conservation Need, we are evaluating the occurrence and impact of neonicotinoid pesticides on individuals. Together with Dr. Than Boves from Arkansas State University and funded by Arkansas Game and Fish Commission's State Wildlife Grant Program, graduate student Connor Gale and I are capturing shrikes and collecting blood and fecal samples from adult and nestlings that inhabit a variety of row-crop habitats as well as more natural grassland and pasture habitat. We are also capturing adult birds across seasons in these same habitat types to assess how pesticide concentrations and potential impacts vary between growing and non-growing seasons. We are also monitoring marked birds to better estimate survival and nests to assess reproduction. These results will inform management by state and federal agencies regarding how to conserve shrikes in human- modified habitats and may elucidate one of the major threats to population viability.