eggs, as the mixture seems to lose much of its scent quality when maggots develop in it. This preparation may be used within three days after mixing, but it is more lasting and penetrating when it is about a month old.

Fish scent alone gives excellent results, but several modifications have been found highly effective. To the decomposed fish as a basis may be added mice, beaver castors, musk glands from minks, weasels, and muskrats, and the bladders of coyotes and bobcats. Oil gives body to the scent and to a certain extent prevents freezing. If the mixture appears too thin, glycerin, brains, fish oil, butterfat, or other animal fat, such as that from woodchucks and ground squirrels, may be added.

The hunter may commence with a quantity of ground fish placed in a large galvanized-iron container, similar to a milk can, and as the original lot is used on the trap line, he may replenish it by adding more fresh fish and others of the ingredients mentioned. The addition of new material from time to time seems to improve the desirable qualities of the scent mixture.

Figure 4.—Details of placing scent set on cleared space between the trail and a clump of higher weeds or grass used as a scent post. Between the trap set and the scent post may be buried a jar having perforated top and containing cotton saturated with oil of catnip; or other scent material may be sprinkled on the clump of weeds to lure the bobcat to the trap

Catnip Oil as a Lure

Oil of catnip, diluted in the proportion of 35 drops of the pure oil to 2 ounces of petrolatum, has proved an effective lure in bobcat trapping. As this is a fine oil, the petrolatum is used to give it body, and this tends also to prevent loss of the scent when exposed to rain. Pure catnip oil is manufactured at a few places in the United States, but if the pure oil is not obtainable, the leaves of the catnip plant may be boiled to a pulpy consistency in water, and this will produce a mild tincture of catnip which can be drawn off. Catnip in this form has been used as a lure by some trappers with a fair degree of success. A few drops of the mixture of petrolatum and pure catnip oil, or of the tincture, should be placed on the scent spot every third day.

Some Biological Survey hunters employ this lure by burying at one side of a bobcat runway a small glass jar or bottle (fig. 4) into which has been dropped gauze or cotton batting, saturated with catnip oil. The mouth of the container is left open, but level with the ground, and is protected by a perforated top. If the top is bright, it should be made inconspicuous by moistening it, and while wet brushing it over with dust or sand. Trap sets placed, as described around such scent points have accounted for many bobcats.

Care in Details

Success in trapping, whether for bobcats or for other predators, is in many respects dependent upon the trapper's attention to what might seem to be minor details. While digging holes for the sets it is well for the trapper to stand or kneel on a "setting cloth," which is made of canvas or a piece of sheepskin or calf hide about 3 feet square. Human scent on the canvas may be avoided by previously burying the cloth in an old manure pile. The dirt removed from the place where the trap is bedded may be piled on the setting cloth. Surplus dirt not needed for covering the trap should be scattered evenly on the ground at some