BOBCAT is the name by which the wild cats of the genus Lynx are known in most of the United States, particularly the warmer parts—West and Southwest. Though related to the mountain lion, or cougar, both being members of the same family, the bobcat is a much smaller animal and of somewhat different habits, so far as the selection of prey is concerned. Its larger cousin, the Canada lynx, is found in the northern, more forested, parts of the United States and in Canada. The economic relations of the two are similar, except as forest-dwelling habits are modified by the bobcat's environment of plains and deserts in the Southwest. The bobcat has keen eyesight and a good sense of smell, though the latter is not so acute as in the wolf or the coyote. Most of its hunting for food is done at night, and the animal is aided by sight rather than by scent. The advance of settlement and the occupation of the bobcat's former ranges for stock raising have not so much crowded back this predator as they have given it a new and satisfying provender, particularly in the young of the flocks and herds of the stockman and the poultry of the farmer. Control of its depredations at times becomes necessary to man's economic welfare.
|Washington, D. C.||Issued June, 1931|
For sale by the Superintendent of Documents, Washington, D. C. – – – – – Price 5 cents
|Nature of depredations||1|
|Where to trap||2|
|"Blind" trap sets||2|
|Scented trap sets||3|
|Preparation of scent||4|
|Catnip oil as a lure||5|
|Care in details||5|
|Rust on traps||6|
|Paper trap pads||6|
TRAPPING has been found to be one of the most effective methods of bobcat control. On its wild ranges the bobcat feeds to a large extent upon rabbits and other injurious rodents, but it preys also upon such valuable forms of wild life as antelope, deer, and other game animals, especially the fawns, and on wild turkeys, quail, and other ground-nesting birds. With human occupation of its former haunts, it finds in the young of domestic livestock very satisfactory substitutes for its ordinary fare in the wild. When its food is less easily obtained in nature than among the flocks and herds of the range country, it may become exceedingly destructive to domestic livestock, especially to sheep during the lambing season, to pigs, goats, and calves, and to poultry. The depredations of bobcats in parts of Arkansas in recent years have made hog raising on an extensive scale impracticable in such localities. Losses caused by this predatory animal among sheep are particularly severe when lambing is conducted on the open range and the lambing grounds are in close proximity to the broken, rough, rocky canyons that favor the presence of the bobcat. Sheepmen often choose such rugged country for lambing grounds because of the protection it affords against storms.
On gaining entry into a flock of sheep at lambing time, commonly under cover of darkness, the bobcat carries on its depredations in such manner as to cause little commotion there. The lamb is usually killed by a characteristic bite on the back of the neck or head, and then it is pulled down to be eaten. If its lust for killing is not satisfied, the bobcat may kill other lambs by the same method, continuing its work quietly until a large number have been destroyed. A single bobcat has been known to kill 38 lambs in this manner in one night.
Bobcats are easily caught in traps of the common double-spring steel type, in sizes 2 and 3. Such traps have been used by many generations of trappers, and although deemed inhumane by some persons, no better or more practical device has yet been invented to take their place. The brief description here presented of trapping methods to be used in bobcat control is based on field experiences of Federal and cooperative trappers who have applied methods developed by the Bureau of Biological Survey.
In selecting a site for trap sets, one should be guided to a large extent by the tracks of the animal (fig. 1) and by other traces of its presence, which are commonly found in the rugged recesses of the open range. Such places as leached limestone ridges, limestone cap rock, or eroded granitic canyons containing an abundance of small caverns and holes surrounded by rather extensive underbrush form the ideal habitat of the bobcat. This may be in low-lying country or in adjacent higher mountainous areas. Though it is advisable to use the greatest caution in setting bobcat traps, the care with which the art is practiced need not be so great as in the case of the wolf or the coyote.
When the trail of a bobcat has been found, by track or sign, along, or leading from its rocky lair, traps may be placed in either double or single sets. If the trail is not frequently used by livestock also, or by such big-game animals as deer, the so-called "blind" trap set may be employed. This set is called a blind because no lure or scent need be used around it when completed.
Whether single or double blind trap sets are employed, they should be placed in holes dug directly in the trail of the bobcat close to such an obstruction as an exposed root, a rock, or a clump of weeds, for the bobcat seldom fails to step over rather than on such an obstruction in its path. (Fig. 2.) If the double set is to be used, the trap holes should be only about 1 inch apart, separated just far enough to prevent interference of the jaws when the trap is sprung. Each hole should be dug only slightly larger than the size of the trap and just deep enough to hold the set trap and allow this to be slightly lower than the level [Pg 3] of the surrounding ground. When two traps are used, they may be joined together with a lap link at the ends of their chains, which in turn may be attached to a stake pin driven slightly below the ground level; or a drag may be used either made of wrought iron or consisting of a fairly heavy stone. The drag should be bedded under the traps, in which case more excavating will be required. It is well to have a free-acting swivel at the top of the stake pin to prevent a captive animal from twisting and breaking the trap chains attached to it.
After the trap has been firmly bedded it is advisable to cover it with fine pulverized earth similar to that found in the mound of a pocket gopher. This will do for the spring of the trap. Dry and finely pulverized horse or cow manure may be more advantageously used to cover the inside of the trap jaws. Care should be taken to keep all loose dirt from getting under the pan and to see that there is an open space beneath it of at least a quarter of an inch.
A trap pad made of canvas or of old descented slicker cloth for finally covering the pan should now be placed on the inside of the jaws; then over all should be sprinkled dry dirt to the depth of a quarter to a half inch, of the same color as the ground surrounding the trap. The spot where the trap is buried should be left in as natural a condition as possible.
A scent attractive to bobcats may be used to advantage to lure the animals to trap sets. When scenting is resorted to, however, the traps should not be placed in the runway proper, but on either side of it, or on one side only, and parallel to Sets the trail. They should be set in the same manner as described for the blind sets, between the trail and the spot selected for scattering the scent. (Fig. 3.) This spot should be no more than 6 to 8 inches from the trap. In placing the scent, advantage should be taken of any stubble, bunch of weeds, exposed root, or object known as a scent post. These are so termed from the fact that they are the places selected by the animal for voiding urine or feces.
Bobcats usually have their scent posts slightly off the trail, on stubble of range grasses, on bushes, or even on old bleached-out [Pg 4] carcasses. Where the ground conditions are right for good tracking, natural scent posts may be detected by the claw scratches and the small mound of dirt where the bobcat has covered its excrement. Such habits are similar to those of house cats. In passing along its trails, the bobcat will usually revisit these scent posts.
When natural scent posts can not be readily found, one may be easily established along the determined trail of a bobcat by dropping scent (of a kind to be described) on a few clusters of weeds, spears of grass, or stubble of low brush. The trap should be set between the trail and the place scented, about 6 or 8 inches from each. (Fig. 4.) Any number of such scent stations may be placed along a determined trail. The farther from the trail a trap is set, however, the more scent will be needed. For dropping the scent, a 2 to 4 ounce bottle fitted with a shaker cork may be used.
The basis of the scent may be any kind of fish, but oily varieties, such as sturgeon, eels, suckers, and carp, are preferred. The flesh should be ground in a sausage mill, placed in strong tin or galvanized-iron cans, and left in a warm place to decompose thoroughly. Each can must be provided with a small vent to allow the escape of gas, otherwise there is danger of explosion. The aperture, however, should be screened with a fold of cloth to prevent flies from depositing 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.
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.
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 [Pg 6] some distance from the set. It is well also to wear gloves while setting traps, and to use them for no other purpose, though the precautions against arousing the suspicion of bobcats are less necessary than those in trapping wolves and coyotes.
Rust on traps.—Rust is often the cause of the failure of traps to spring properly, particularly when the trap pan rusts on its post. Most steel traps are so constructed that when the trap pan is moved back and forth it will spread the joint and thus permit the pan to work freely. Putting a few drops of fine oil on the post, as well as in the slots that hold the jaws at the base of the trap, will overcome such difficulties.
Frozen ground.—When the ground is frozen it is difficult to keep the traps in working order. Some hunters overcome this difficulty by lining the bottom of the hole in which the trap is to be bedded with clean coarse cotton or wool, and by packing more of this material around the pan, springs, and jaws after the trap is placed. When the ground is frozen, the dirt cover for the set can be made of such debris as is found on ant hills, or by using dead leaves or the fine earth obtained under spruce, fir, hemlock, or aspen trees.
Deodorizing traps.—When received from dealers or manufacturers, traps frequently smell of grease, perspiration from human hands, or other odors caused by contact with various kinds of merchandise in the course of shipment. As some of these odors are likely to arouse the suspicion of predators, it is advisable to clean all traps before using them. This may be done by boiling them in a tincture of sage leaves, or of leaves from other native trees. Common soil is a good deodorizer, but it acts slowly. Simply burying the traps for a few days in a manure pile (the odor from which does not arouse the predator's suspicion) will often remove all other odors. It is better, however, before using traps to clean them by boiling, as mentioned. Never attempt to burn off an odor over a fire, as this may destroy the temper of the springs and make the trap worthless.
Paper trap pads.—Paper pads are not dependable, as they are usually too smooth to hold the covering of soil. This is soon swept' off the paper when the trap is set in a windy place, and when this is gone the trap is exposed. Furthermore, rain will readily soak a paper pad, causing it to break or collapse and expose much of the set. Another objection to paper pads is that when an animal steps lightly into a trap jaw, resting its toes barely inside of it but not on the trap pan, it is likely to hear the rustle of the paper under its foot as well as to feel its smoothness. The result is that it will be shy of that particular spot, and thus a catch is lost. Trap pads made of fairly thick canvas or woven wire of fly-screen consistency are therefore preferable to paper pads. Such trap pads should be free from all odor, and when not in use should be kept in a clean container, such as the 1-pound cans used for ground coffee.
The trap may be reset after a bobcat has been caught, the same spot being used if the ground and the natural surroundings have not been too badly scratched up or otherwise defaced, and if evidences of disturbance can be cleared away. It may be highly desirable to reset the sprung trap in the same place, particularly if other good spots are lacking for scenting or for taking advantage of the natural obstructions needed for blind sets.
U. S. GOVERNMENT PRINTING OFFICE: 1931