Hints on Mountain-Lion Trapping

In Short

This 1933 publication by the Bureau of Biological Survey serves as a practical handbook for livestock producers and federal field staff managing large feline predators in the American West. The text outlines the geographic presence, feeding behaviors, and physical capabilities of the mountain lion before detailing precise field methods for capture. It covers hound tracking, trap selection, territorial indicator placement, and the specific application of catnip oil attractants. Written from decades of field experience, it stands as a historical blueprint of early twentieth-century wildlife management and federal predator control strategies.

The Story

The text opens by outlining the geographic distribution and predatory habits of the mountain lion (Felis concolor) across the western United States. Positioned as the primary natural enemy of deer, the animal is identified as a major economic threat to western range operations, where it preys heavily on young colts, lambs, kids, and mature stock. The author establishes that while wilderness expanses will preserve the species from total eradication, localized control remains essential for the survival of range livestock.

From this ecological baseline, the manual evaluates control techniques. It dismisses chemical poisons as unsafe for hunting dogs and unsuited to the task, advocating instead for systematic tracking and trapping. Trapping relies on understanding the target animal’s routine. Because mountain lions travel long distances along established natural boundaries, hunters target structural terrain features, such as low saddles on mountain divides where lions mark territory with distinct scratch hills.

The core of the text provides step-by-step assembly instructions for field sets. The guide details how to construct carcass sets around fresh kills, arrange blind sets in narrow defiles, and deploy catnip oil lures on trees. To build a long-lasting scent station, the author describes blazing a tree, mounting a perforated tin pie plate containing a catnip-and-petrolatum sandwich, and bedding heavy steel traps directly below the trunk.

The manual closes with precise mechanical adjustments designed to reduce accidental captures. Instructions explain how to bury heavy wrought-iron drag chains, bed the trap mechanisms flush with the earth, and disguise the ground using pulverized manure, canvas pan covers, and native soil. To protect non-target species like birds and small rodents, the text details the installation of pan-support springs and wooden twigs set under the trap mechanism. These refinements ensure the trigger releases only under the heavy weight of a mature lion, concluding a comprehensive operational standard for range managers.

How It Unfolds

The scope of the predator problem The author outlines the territory, feeding patterns, and physical power of the mountain lion across the Rocky Mountain and desert ranges. He highlights the animal's economic impact on western livestock operations and notes its exceptional traveling endurance.

Selecting tools and scent lures The manual evaluates control methods, rejecting poison in favor of trained hounds and heavy steel traps. It details the preparation of catnip oil combined with petrolatum to exploit the feline scent response.

Constructing the tree scent station The guide presents a specific method for mounting a perforated tin pie plate over a tree blaze to create a multi-month scent lure. Trapping sets are then placed at the base of the tree along narrow travel corridors.

Bedding the trap mechanism The text describes digging precise excavations near scent stations, trail bottlenecks, or fresh carcasses to conceal double-prong iron drags and heavy steel traps. Trappers are instructed to use sticks and stones to guide the animal's footstep directly onto the concealed pan.

Fine-tuning pan tension and site restoration The final section details site concealment using setting cloths and pulverized earth to hide human disturbance. It concludes with methods for underpinning trap pans with twigs or specialized springs to prevent non-target birds and rodents from springing the set.

The People

Stanley P. Young As Principal Biologist in Charge of the Division of Predatory Animal and Rodent Control, Young serves as the authoritative voice of the manual. He wants to standardize field practices across western ranges to protect rural livestock economies while maintaining a practical approach to wildlife management.

Biological Survey Hunters These field agents represent the operational backbone of federal control efforts. Possessing exceptional physical stamina, they spend up to ten consecutive hours trailing lions through rugged wilderness, testing trap designs, and refining scent lures through direct observation.

Western Stockmen and Game Conservationists Representing the primary audience, these individuals seek to protect their herds of colts, lambs, and cattle from severe predation in isolated terrain. They contend with the physical challenges of open-range stock raising and depend on systematic federal instructions to secure their livelihoods.

The American Mountain-Lion Depicted as a powerful apex predator weighing over 200 pounds, the mountain lion acts as the primary focal point of the text. Driven by an appetite for deer and domestic stock, it moves silently across long wilderness circuits, leaving behind scratch hills and marked trails that ultimately reveal its position to trappers.

In Its Own Voice

"Game conservationists recognize it as the greatest natural enemy of deer."

The author establishes the predator's ecological role within western ranges before addressing its impact on domestic herds.

"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."

This observation highlights the manual skill and careful attention to detail required of an effective field trapper.

"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."

The text notes the collaborative field trials that led to the development of standardized scent stations.

What It's Really About

Beneath its procedural directives, the book documents an era defined by the systematic management of the American frontier. It captures the tension between wild apex predators and expanding rural agricultural economies, illustrating how federal agencies applied biological research to reduce livestock losses.

The text reflects an early institutional attempt to balance control with preservation, explicitly noting that wilderness areas will continue to support lion populations outside active range zones. Mechanically, it frames successful control not as brute force, but as an intimate understanding of animal scent, movement, and habit.

Why Read It Today

This work appeals to environmental historians, historical researchers, and readers interested in early twentieth-century wildlife policy and frontier woodcraft. Reading it offers an unvarnished look into historical federal predator management, conveying a strong sense of the practical realities faced by range workers in the 1930s.

The writing is direct, highly technical, and completely devoid of romantic embellishment. Readers should note that the text focuses squarely on trap construction, animal tracking, and lethal capture methods, reflecting period attitudes toward predatory species that may prove stark to modern readers. What remains memorable is the manual's remarkable attention to micro-detail—from constructing catnip-smear sandwiches inside tin pie plates to calibrating tension twigs beneath steel trap pans.