A Field Evaluation of the Efficacy of Milorganite as a Repellent for Non-Venomous Rat Snakes (Elaphe obsolete)

The objective of this study was to evaluate the efficacy of Milorganite® as a repellent for rat snakes. Milorganite® is the bio solids by-product left from the activated sludge process from the Milwaukee Metropolitan Sewer District. During 3, 7-day release periods, 5-6 mature rat snakes were placed within a 0.1ha plastic fence enclosure intended to impede escape. The enclosure contained natural and artificial hides and water. Snakes were fitted with an externally attached radio transmitter with location of each snake determined 3 times per day by radio telemetry and visual confirmation. During the first 2, 7-day period, with no Milorganite® treatment, snakes were contained within the enclosure for a similar (p\u3e0.05) duration of 9.1h±1.8 and 9.4h±1.8 respectively, before escaping. Prior to release of snakes in period 3, a total of 907.2g of Milorganite® was applied by hand in a 20cm width strip along the interior perimeter of the enclosure fence. During period 3, 6 snakes were maintained within the enclosure longer (p\u3c 0.005) compared to periods 1 and 2, with an average containment time of 23.5h/day±0.5. Total snake-hours that animals were maintained in the enclosure was higher (p\u3c0.005) during the Milorganite® treatment (164.0h±1.4) compared to non-treated period 1 (64.0h±1.8) or period 2 (66.0h±9.0). All snakes remained within the enclosure throughout the 7-day treatment period. One snake died on day 6, posttreatment from unknown causes. Results of this study suggest Milorganite® was effective as a repellent for the rat snake under these experimental conditions

Field Evaluation of Two External Attachment Location of Radio Transmitters on Non-Venomous Rat Snakes (elaphe obsolete)

The objective of this study was to determine the effectiveness of external attachment of radio transmitters at one of two locations on mature rat snakes (Elaphe obsolete). Transmitters were attached to mature snakes (n = 10; 136.7cm ± 6.4) on either the ventral surface (n = 5) or dorsal-lateral surface of the rib cage (n = 5), approximately 25cm cranially to the cloaca. Transmitters (18mm × 8mm × 2mm) were attached by one drop of acrylamide gel glue to the adhering side of camouflage duct tape (20cm × 30mm), a single drop of glue on the exposed side of the transmitter, and secured by wrapping the tape to the snake’s body with the transmitter in the appropriate location. A second piece of duct tape (20cm × 40mm) overlapped and secured the first piece of tape with the transmitter. Snakes were placed in a 0.1ha plastic fence enclosure, (128.5cm ± 0.5 height, and 17.1° ± 0.5 inward slope) in an unimproved pasture with numerous hides, water and food. Snakes (n = 4) shed their skin and the transmitter, within 6- 17d post-attachment (11.7d ± 2.4). Snakes (n = 4) escaping the enclosure and not located, ranged from 1- 21d post-attachment, (12.3d ± 4.7). There was no difference (p \u3e 0.05) in functional days snakes were located by radio telemetry due to attachment site or sex. Transmitter reception distance was typically \u3c 50m and often problematic. Results of this study suggest that the location of external attachment of transmitters had no influence on duration of effectiveness. However, shedding and limited telemetry range under these conditions should be considered to determine if the methodology is appropriate for the desired objectives

Anatomy of a Snake Fence Intended to Prevent Escape of Non-Venomous Rat Snakes (Elaphe obsolete) from an Enclosure

We constructed a fence enclosure with the objective of preventing escape of rat snakes (Elaphe obsolete) as part of a repellent study. A 25cm trench was dug in a 30m × 30m square (0.1ha) in an unimproved pasture. Wood posts (8.9cm × 8.9cm × 2.0m) were secured on corners and at 15m intervals between each corner at an average height of 128.5cm ± 0.5 height with an inward slope of 17.1o ± 0.5. Steel T-posts (2.0m) were erected to a similar height and angle at 4m intervals between wood posts and fitted with plastic insulated caps. Three strands of 17-gauge wire were secured to the top, middle and 10cm above the ground of each post. Plastic sheeting (3.04m × 30.4m × 4mm) was draped over the suspended wires with the bottom 25cm secured within the trench with dirt. All overlapping seams of plastic were secured with polypropylene tape. A single strand of 17-gauge electric fence wire and a strand of electric polyfence tape were attached by duct tape to the top of the inside of the plastic fence. An additional strand of electric polyfence was attached by duct tape to the plastic 20cm above the ground. A loop of the electric polytape was also attached in each corner and connected to the wire and polytape on the top and lower strand of polytape. The electric fence strand and all polytape was energized by a solar powered charger with an output \u3e 5000v. During two releases of 5 mature rat snakes (n = 10; 136.7cm ± 6.4), containment within the enclosure was similar (p \u3e 0.05), and limited to 9.1h ± 1.8 and 9.4h ± 1.8 respectively. Video analysis indicated snakes were climbing the electric charged polyfence tape and escaping over the fence without evidence of receiving an electric shock. This fence design was not sufficient to maintain mature rat snakes