Traps set along a trail and near an obstruction meant to divert the mountain-lion close to a scratch hill, are only partly successful. The trapper may, however, take advantage of the mountain-lion's keen sense of smell by dropping a few drops of oil of catnip in the center of the undisturbed scratch hill, as a lure.
Why catnip is so attractive to members of the feline family is not yet fully known. Experiments have indicated that it produces sexual excitation and also that it has a soothing effect on the nervous system, similar to that of opiates on man. In some of the larger circuses catnip has been used for years in gentling animals of the cat family. The use of catnip oil in this country to lure members of this family within trapping distance has been remarkably effective.
When pure catnip oil is obtainable it should be used, diluted with pure petrolatum, in the proportion of 40 drops of the catnip oil to 2 ounces of petrolatum. A catnip lure so placed that it will last a long time has been experimented with by members of the Provincial Game Conservation Board of British Columbia, and later by the writer in the United States. Prepared as follows, it promises to increase the effectiveness of trapping in mountain-lion control:
Figure 3.—A 2-trap "blind" set for mountain-lions. In the saddle of a divide the traps are placed in the trail where it narrows. A small stick or other obstruction should be put between the traps and one at either approach, to make the lion step into one of the traps rather than between or over them
The petrolatum-diluted catnip oil is smeared thinly over a piece of cotton batting about 8 inches square, and this is covered with another piece of the same size. The catnip-oil sandwich thus made is placed on an ordinary tin pie plate, brown in color, so that the bottom will be inconspicuous against the bark of a tree. Two or three feet from the ground a tree is blazed to make the sap flow, the cut being made in the shape of the plate. The plate is spiked over this blaze, with the batting next to the tree so that the cotton will be kept moist by the sap. To prevent its being torn out by a bear, the plate should fit snugly into the cut, the lower edge flush with the bark. The bottom of the plate should be perforated with small holes made with a shingle nail, so that the scent will escape slowly. The plate should be shaded from the sun as much as possible.
Such scent stations should be placed on trees along creeks where mountain-lions are known to travel, particularly near deer trails that lead to water. They are probably best placed on trees in narrow canyons, where the chances of successful trapping are greater because of the narrowness of the path along which the mountain-lion must travel. The writer has known catnip pans to be visited by mountain-lions in such places as long as 6 months after placement, and in British Columbia the game authorities report a lion's visit to a station 10 months old. After the scent station is made, traps should be set, as described later, near the base of the tree. The mountain-lion, attracted by the catnip odor in the plate, steps into the trap when approaching the lure.
Setting the Traps
The hole for the trap set should be dug about 15 to 20 inches from a carcass, a single undisturbed scratch hill, or a tree on which a scent station has been placed, or directly in a trail where it narrows naturally or is made to narrow by rocks, brush, or other obstructions placed at the sides. ([Fig. 3.]) The hole should be only slightly larger than the trap, and just deep enough to hold the set at a level slightly lower than the surrounding ground, with the drag and chain buried beneath it. The drag, which should preferably be of ½-inch wrought iron, should be attached to one end of the chain by a figure-8 swivel and it should end in two well-curved prongs. ([Fig. 1.]) Bedding the drag under the trap, of course, requires more excavation. The drag chain should be at least 8 feet long and attached to the base of the trap or to one of the springs. At scratch hills it is well to place a trap on either side, the springs at right angles to the known direction of approach. In a trail the traps should be in line, the springs at right angles to the direction of travel. Experiments have proved that most of the larger predators, and particularly the mountain-lion, tend to avoid stepping directly on any hard object in a path. Knowing this tendency, the trapper may place a stick or a stone between the two traps and another at each approach; these will cause the animal to break its gait and step into one of the traps rather than over or between them. In approaching a scratch hill, a scent station, or a carcass where sets have been made, or in passing over a blind set in the trail, the predator is usually caught by one of the forefeet, though it may step into a bedded trap with a hind foot. No scent is used at carcass or blind sets. (Pp. [4], [6].)