space there is at least one-fourth inch deep. The trap pan should be covered by a pad made of canvas or old descented slicker cloth, and cut to fit snugly inside the jaws, and all should then be covered with finely pulverized earth, leaving the immediate area looking, as nearly as possible, as it did before the trap was buried. Finishing such a task properly and thus leaving the ground over the trap in a perfectly natural condition so that it blends with the surrounding area is an art that requires much practice.

Figure 4.—Devices to prevent capturing small animals and birds in traps set for mountain-lions or other predators: A, Fan supported by twig (grass or a light coil spring may be used); B, splint support; C, forked-twig support; D, Biological Survey pan spring

Traps Accidentally Sprung

When traps are set near carcasses additional care should be undertaken to underpin the trap pan so that it will not spring under the weight of a magpie, buzzard, or other carnivorous bird that may be attracted to the carcass.

In forested areas a mountain-lion hunter may find his traps sprung by small animals, for squirrels and other rodents (and sometimes small birds) may dig or scratch around and between the jaws of the trap. Unless the trap pan is properly supported, these animals are unnecessarily endangered, and in addition the trap is frequently sprung. This may be prevented by setting the trap pan so that it will carry a weight of several pounds.

One simple way of underpinning the trap is to place a small twig perpendicularly from the base snugly up to the middle point of the pan. Instead of the small twig, some hunters use a fine coiled-steel spring. Such contrivances will permit the trap pan to carry the weight of the smaller mammals or birds without endangering them or releasing the trap jaws and thus spoiling a set well placed for a mountain-lion. Devices adjusted to mountain-lion traps to prevent their being sprung by small mammals and birds are illustrated in Figure 4. The Biological Survey pan spring (fig. 4, D), recently developed in this bureau can be readily attached to the No. 14 steel trap used for mountain-lions. A slightly larger spring is required for the No. 4½ trap. A patent on this device has been applied for, to be dedicated to public use.

Care in Details

In trapping, attention to simple details is essential. Though the mountain-lion trapper need not be so cautious about human scent as the trapper of wolves or coyotes, it is well, when placing a trap, for him to stand or kneel on a setting cloth, if for no other reason than convenience. This cloth may be about 3 feet square and made of canvas, slicker-coat material, or the skin of a sheep or calf. It will also help to avoid disturbing the ground about the trap set. Excavated soil can be placed on it, and that not needed in completing the work can thus be easily removed. In addition, at the completion of a set, the trapping equipment can be rolled up in it and carried away. Minor trapping details include removing rust from traps, boiling them in water to eliminate the conspicuous fresh odors noticed when they come from the manufacturer, carefully repairing traps with faulty springs, taking care that the trap pan moves freely on its post, and seeing that the jaws are adjusted to close snugly and rapidly. Without attending carefully to minor details, no farmer or stockmen can expect success in trapping