Caffeine Formulation for Avian Repellency

Authors

Scott J. Werner, USDA-APHIS-Wildlife ServicesFollow
John L. Cummings, United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research CenterFollow
Shelagh K. Tupper, United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center
Jerome C. Hurley, United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center
Randal S. Stahl, USDA-APHIS-Wildlife ServicesFollow
Thomas M. Primus, United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center

Document Type

Article

Date of this Version

June 2007

Comments

Published in JOURNAL OF WILDLIFE MANAGEMENT 71(5):1676–1681; 2007.

Abstract

Nonlethal management alternatives are needed to reduce avian depredation of agricultural crops. Caffeine has promise as an effective, economical, and environmentally safe avian repellent, yet formulation improvements are needed for field applications. We included sodium benzoate in subsequent formulations to enhance the solubility of caffeine. Red-winged blackbirds (Agelaius phoeniceus) discriminated between untreated rice and rice treated with 250 ppm or 10,000 ppm caffeine and sodium benzoate in captivity. We observed a positive concentration–response relationship among birds offered rice treated with 250 ppm, 1,000 ppm, 2,500 ppm, 5,000 ppm, 10,000 ppm, or 20,000 ppm caffeine and sodium benzoate. Relative to the pretreatment of the concentration–response test, repellency was .85% for rice treated with our 2,500- to 20,000-ppm treatments. We conducted seed germination experiments and associated residue analyses to evaluate the potential phytotoxicity of various caffeine formulations under controlled environmental conditions. The optimized formulation enhanced the solubility of tank mixtures and ameliorated the negative impacts of seed treatments to germination. Our caffeine formulation provides an applicable, nonlethal alternative for managing blackbird impacts to agricultural production.