Proceedings of the Vertebrate Pest Conference

The objective of this study was to determine the effectiveness of Milorganite® as a potential repellent for non-venomous snakes. Milorganite® is the biosolids by-product left from the activated sludge process from the Milwaukee Metropolitan Sewer District. Within a climate-controlled building, two triangular enclosures consisting of panels (2.4 × 1.2 m) resulting in 2.6 m2 floor surface area, were secured to plastic floor covering and provided with cypress mulch and a container of water. Corners of the enclosure were demarcated using a 63.5-mm monofilament line placed 10 cm above the floor, providing a .09-m2 visible triangle of floor surface area. Round metal containers (8.3 × 3.0 cm) were secured to a board and individually placed within each enclosure corner. Treatments consisted of a control, or the addition of 250 mg or 500 mg Milorganite® within respective metal containers, within each corner. Wild-caught snakes (n=20), including rat (Elaphe spp.), corn (Elaphe guttatus), king (Lampropeltis spp.), black racer (Coluber constrictor priapus), and pine (Pituophis melanoleucus) snakes, were placed individually within an enclosure for a 24-hour period. Activity of the snake was digitally recorded using an infrared camera placed above an enclosure. Treatment application was repeated for each individual snake. The amount of time each snake spent within the respective enclosure corners or outside the demarcated areas during the 24-hour period was utilized as an indication of the effectiveness of Milorganite® as a repellent. During the 1440-min trials, snakes spent more time (p<.01) in the control corner (559.9 ± 98.9 min) or outside the demarcated areas (548.49 ± 89.1 min) compared to the 250-mg Milorganite® (214.5 ± 70.1 min) or 500-mg Milorganite® (117.2 ± 21.6 min) -treated areas. While not different (p>.05), there was a trend toward a dose-response effect of the Milorganite® treatment levels. Results of this study indicate Milorganite® demonstrated potential as a snake repellent.