Portal de Periódicos da CAPES

An Experiment with Snake Trapping

1949; American Society of Ichthyologists and Herpetologists; Volume: 1949; Issue: 4 Linguagem: Inglês

10.2307/1438377

1938-5110

Lucas M. Dargan, William H. Stickel,

Species Distribution and Climate Change

T HE value of funnel traps for bull-snake control was demonstrated by Imler (1945). The feasibility of using these traps for snake population study was tested on the Patuxent Research Refuge in 1946 and 1947. Since further work with the traps is not planned for the near future, comments on the method are offered for the consideration of those interested in similar studies. The traps are modeled after those described and figured by Imler, but are 4 feet long and 18 inches wide instead of 6 feet long and 24 inches wide. The smaller size of the traps makes it easier to reach animals in corners or wedged beneath funnels. The smaller traps are also less expensive to construct and easier to transport. Within each end of a trap there is a 14-inch funnel, the inner end of which is 4 or 5 inches above the floor. Each funnel is divided by a vertical partition and hence has two inner openings, each 2 inches wide and 2X2 inches high. The partitions are joined to drift fences. These fences are 12 inches high and extend 25 feet from each end of the trap. A 2-foot wing is placed obliquely at each corner of the trap to help guide snakes into the funnels. Animals are removed through a door in the top of the trap. Traps, fences and wings are made of '4-inch mesh hardware cloth. The traps are not baited. Animals simply come to the drift fence and follow along it into the trap. The traps are therefore exceedingly unselective. They catch everything from insects to mammals. Most animals die unless traps are visited at least once a day. Traps should be covered with boards or vegetation to provide shade, even if they are in woods. Few reptiles will die in the traps if this is done, but many amphibians, birds and mammals will still succumb. For this reason funnel traps should not be recommended to the public for capture or control of snakes or other animals. When carelessly tended they are wholesale slow death traps. Game and other legally protected animals are among those killed. The number of deaths probably could be reduced by keeping food and water in the traps. This might also increase the catch. It would, however, add greatly to the difficulty of the project. Our traps were set in an upland pine-oak woods where other studies in progress made possible frequent visits. Sixteen traps were arranged in a grid of 4 rows of 4 traps each, with traps 330 feet apart. The area within the grid was 22.5 acres. Both size of area and number of traps were far too small, as shown below, but circumstances made a more extensive trial infeasible. The drift fences were placed to meet fallen logs, small ravines or other natural objects that might direct animal movement. One corner of the grid was 290 feet from a 50-acre lake. The traps were operated from the last week of May until mid-November in 1946, and from the first week of April until mid-November in 1947. EFFECTIVENESS OF TRAPS.-Upland pine-oak areas on the refuge are con-