Evaluation of lime as an avian feeding repellent

We evaluated the effectiveness of dolomitic hydrated lime as a feeding deterrent to captive brown-headed cowbirds (Molothrus ater) and Canada geese (Branta canadensis) during July-September 1995. We conducted 1- and 2-choice tests using grains with caged cowbirds and geese, and applications of lime to turf in dry and slurry form for geese. Lime mixed with millet or whole-kernel corn at 25, 12.5, and 6.25% (g/g) reduced cowbird and goose feeding in 4 day, 2-choice (treated or untreated grain) cage trials. Reductions in total food intake occurred for both species during similar 1-choice tests with lime (25% [g/g]) and millet or corn. Body mass of cowbirds and geese increased or remained constant during 2-choice tests. In contrast, body mass declined for both species during 1-choice tests. Application of lime to enclosed 10- x 10-m-grass plots in powder or slurry form at an application rate of 544 kg/ha also reduced goose feeding on treated plots for 2-3 days. Mean numbers of geese and mean fecal mass on control and treated plots were similar during both turf experiments. No phytotoxicity of grass was observed greater than or equal to 40 days posttreatment. We recommend additional studies to determine the lower limit of repellency of lime to various bird species and its utility for turf and crop damage reduction.