Management Tools and Their Applications
The goals and objectives of Maryland's Furbearer Management program are to ensure the ecological integrity of native furbearer species, and balance furbearer populations that contribute to the perpetuation of healthy ecosystems. All native species are integral and irreplaceable components of functional ecosystems. However, inherent population growth characteristics of many furbearers allow unchecked growth to reach levels that negatively impact natural systems. Likewise, non regulated populations of these same species may ultimately impact public health and safety, and/or result in nuisance animal interactions with the general public. As the agency charged with stewardship of all wildlife species, it is the Department of Natural Resource's (DNR) commitment and responsibility to manage furbearers in a manner that enhances ecosystems while simultaneously minimizing negative impacts to Maryland's citizenry.
The professional wildlife conservation community universally endorses traps and trapping as critical and essential wildlife management tools. Highly structured and replicated studies have repeatedly shown that leghold (foothold) traps are the only efficient, practical, and humane live capture/control tool currently available for many furbearer species. They function as the primary and most selective live restraining device currently available and in widespread
Trapping, and more specifically the use of leghold (foothold) traps, is fraught with controversy and pervasive misinformation. Fundamental management decisions that were once based on sound science have now entered the arena of public debate and are subjected to increased scrutiny. Consequently, the following text and salient documentation will attempt to objectively clarify the role of legholds (footholds) and trapping in furbearer and ecosystem management strategies.
By necessity, leghold (foothold) traps are a decisive and entrenched part of most trapping strategies, and it is therefore virtually impossible to sequester them from any discussion concerning trapping. It should be assumed that, unless otherwise mentioned, any further reference to traps or trapping shall include use of leghold (foothold) traps. It should also be noted that leghold (foothold) traps are live capture restraining devices that allow release of captured animals.
Governmental wildlife agencies, universities, conservation organizations, international species recovery groups, and public health officials routinely use, or prescribe the use of traps and trapping for a variety of projects. These include, but are not limited to: research, reintroduction, ecosystem management, endangered species recovery, population and disease management, critical habitat protection, exotic and invasive species control, protection of private property, and control of crop and livestock depredations (1).
The WILDLIFE SOCIETY and the INTERNATIONAL ASSOCIATION OF FISH AND WILDLIFE AGENCIES (IAFWA) are the largest international organizations representing professional wildlife conservation employees and governmental wildlife agencies. Both groups actively support and promote trapping and leghold (foothold) traps as invaluable management tools. Position statements by these organizations relative to trapping include the following excerpts:
The Wildlife Society
The policy of the Wildlife Society in regard to trapping is to: “Support the use of regulated trapping for sustained harvest of some species of furbearers as an effective method for managing or studying furbearers, controlling damage caused by furbearers, and at times reducing the spread of harmful diseases, and for economic benefit, subsistence, and as a legitimate recreational activity” (2).
International Association of Fish and Wildlife Agencies
Resolution No.1 on Traps, Trapping And Furbearer Management states in part:
" WHEREAS, regulated trapping guided by responsible wildlife management principles is a safe, efficient, and necessary means of capturing individual animals without impairing the survival of furbearer populations or damaging the environment; and
" WHEREAS, lethal harvest or control techniques are not feasible or appropriate in all situations and
"WHEREAS, live restraining traps often offer advantages over other techniques in efficiency, safety to humans and domestic animals, release of non target animals and lack of adverse environmental effects” (3).
Animal Welfare and Trap Selectivity
The basic tenants of sound furbearer management dictate that some furbearers have to be captured. By definition, wild animals are free ranging and typically not subject to confinement. Regrettably, it is impossible to capture, restrain, or handle any wildlife species without animals experiencing some degree or level of stress and injury. Similarly, each species has unique physical characteristics and/or behavioral manifestations that predetermine the species specific effectiveness of differing capture devices. While box traps, snares and kill traps work for some species in some applications, for many species and in many circumstances, leghold (foothold) traps are the safest, most ecologically sound, efficient, and humane trap currently available.
In correspondence with Maryland DNR, Dr. Victor Nettles, D.V.M., Ph.D., and former Director of the Southeastern Cooperative Wildlife Disease Study at the University of Georgia's College of Veterinary Medicine, states that after evaluating over 3,500 trapped animals: "as a veterinarian, I condone the relatively short-term injury and pain caused by traps because population control through trapping can alleviate the greater suffering in wildlife associated with disease, parasitism, and starvation. After almost three decades of study of wildlife diseases, I can assure you that there are much worse ways for an animal to die than be captured in a leghold trap” (4.)
Further commentary on the acceptability of leghold (foothold) trap use can be found in the following resolution passed by the INTERNATIONAL UNION FOR CONSERVATION OF NATURE AND NATURAL RESOURCES SURVIVAL SERVICE COMMISSION (lUCN/SSC) which states in part:
“ Whereas, it is often necessary to live trap wolves for research that promotes conservation, and 'Whereas every method of live capturing animals presents a potential danger to that animal, Now Therefore Be It Resolved, that the lUCN/SSC Wolf Specialty Group supports the use of modified steel foothold traps to live trap wolves for conservation research as being the most efficient, effective, and practical method available of catching wolves while minimizing possible injuries. Steel foothold traps represent a method safe enough to be used in any context including wildlife refuges, protected areas for endangered wolf populations” (5).
Concerted efforts between the professional wildlife community, trap manufacturers, and trappers have been undertaken to improve animal welfare. Notwithstanding the major improvements in humane attributes of traps and trapping systems that have occurred during the last 30 years, these same entities have greatly accelerated their efforts during the last decade.
In 1997, representatives of the 50 state wildlife agencies, Canada, Russia, and member nations of the European Union reached multi-national agreements governing the development of ‘Humane Trapping Standards’. Under the auspices of the IAFWA, U.S. and Canadian representatives have initiated the largest systematic evaluation of traps and trapping systems ever conducted. Existing traps, modifications of commercially available traps, and experimental trap types have been tested in efforts to improve the welfare of trapped animals. The results of these investigations will be incorporated in the development of Best Management Practices (BMP’s) guidelines for traps and trapping. The foundation of this monumental initiative is to improve the welfare of trapped animals, while concurrently maintaining adequate efficiency, practicability, and safety standards. Realizing the interdependent complexities of this issue, prudence has mandated an exhaustive testing regime that will ultimately yield scientifically defensible advancements in the humane characteristics of trapping systems.
As of May 2003, over 50 trapping systems for 15 species of wildlife have been evaluated in 32 states. The ‘Eastern Coyote BMP’ has been completed and BMP’s for 7 additional species are tentatively scheduled for 2004. Although incomplete at this time, preliminary data for many species suggest the following (7):
- With few exceptions, there are currently no viable alternatives to leghold (foothold) traps for live capture of many species.
- Various modifications to commonly available leghold (foothold) traps have substantially increased animal welfare properties of some traps in compliance with evaluation guidelines established by the International Standards Organization.
- Not only do leghold (foothold) traps allow the release of unwanted animals, BMP studies document the high degree of selectivity for target animals using these traps. Studies that have included the trapping of thousands of animals have resulted in non target species capture rates as small as 3% of total number of captured animals.
- Contrary to popular belief, the selectivity of leghold (foothold) traps resulted in no non-target captures of threatened and/or endangered species.
Relative Importance of Traps and Trapping as a Management Tool
Trapping and leghold (foothold) traps are the pivotal management tools for modifying population trends in furbearers. Alternative control and/or live capture techniques, including cage traps, hunting, and poisons tend to be more injurious, less effective, and often pose secondary environmental hazards. Leghold (foothold) traps are routinely used to address the following management concerns:
A. Threatened and Endangered (T&E) Species Protection and/or Restoration
Non regulated predator populations possess the inherent abilities to depress recruitment/recovery of several key species. Likewise, high population densities of furbearing species often result in habitat destruction or other ecological perturbations that decrease carrying capacity, displace, and/or preclude survival of additional species. Nationally, leghold (foothold) traps have been employed in innumerable efforts to restore T&E species. In Maryland, DNR has been involved in studies documenting the detrimental effects of red fox predation on nesting waterfowl inhabiting Chesapeake Bay wetland systems, as well as colonial nesting shorebirds (including least terns and critically endangered piping plovers on Assateague Island).
By design, capture devices used to reintroduce extirpated species or augment T&E populations have to ensure minimal injury probabilities for target animals. Nationally, leghold (foothold) traps have been used almost exclusively to capture and reintroduce red wolves, gray wolves, Mexican wolves, lynx, and river otter. Over 4,000 river otter have been released in reintroduction projects conducted in 18 states. The overwhelming majority of these animals are captured by commercial/recreational trappers using conventional leghold (foothold) traps (8).
Maryland DNR has successfully reintroduced river otter to western Maryland and Pennsylvania. Leghold (foothold) traps were used exclusively to live capture otter at donor sites on the Eastern Shore. Viable, self sustaining river otter populations now exist in areas where they had previously been absent for over 100 years.
B. Habitat and Ecosystem Management
Furbearers are essential components of Maryland's divergent ecosystems. Balanced populations contribute greatly to the overall health and viability of these natural communities. Conversely, inflated populations of many furbearers can significantly disrupt the complex interrelationships necessary for the functional health of ecosystems. At high population densities, beaver, nutria, and muskrat have the ability to degrade, destroy or convert existing ecosystems. The net result can often be the total elimination of aligned species dependent on that ecosystem. Deer, squirrels, songbirds, and other forest-associated species are displaced as beaver flood woodlands.
Nutria are invasive, semi aquatic rodents first introduced into Dorchester County, Maryland in 1943. Nutria are a foreign addition to Maryland's natural communities. Therefore, no inherent biofeedback mechanisms exist to naturally control their populations. Consequently, successive population increases and range expansion has resulted in established populations in all eastern shore counties except Cecil. Nutria have also been sighted in Calvert County on the western shore, but it is believed that these are transient animals. Population estimates on Blackwater National Wildlife Refuge, a 10,000-acre parcel located in Dorchester County, have expanded from less than 150 nutria in 1968, to an estimated 35,000 50,000 in 1999 (9).
Loss or degradation of Maryland's coastal wetlands has reached alarming proportions. It is estimated that 65% of these fragile ecosystems have been lost since the 1700s. Nutria feeding behavior damages or destroys existing root mat that binds and secures structural components of functional marshlands. When this fibrous network is compromised by nutria activity, emergent marsh is quickly reduced to unconsolidated mudflats. These areas, in turn, are highly susceptible to erosion processes and are eventually converted to open water, thus eliminating entire ecological systems. Annually, thousands of acres of rich Chesapeake Bay wetlands and the myriad of wildlife species dependent upon them are degraded or lost, wholly or in part, as a result of nutria.
Rapidly expanding nutria population densities, coupled with resultant marsh loss prompted the formulation of the Marsh Restoration Nutria Control Partnership. The 23 entities involved in this working group include representatives from Maryland DNR, University of Maryland, US Fish and Wildlife Service, US Geological Survey, US Department of Agriculture, US Army Corps of Engineers, and 17 additional governmental and private partners.
The partnership is currently initiating a pilot project that is a marriage of applied research and systematic trapping efforts. It is designed to function as a feasibility assessment, and to potentially develop the tools necessary for practical eradication or control of feral nutria populations. Currently, 15 states and numerous sovereignties are enduring established non native nutria populations. The scientific community and officials from these jurisdictions have focused their attentions on this prodigious Maryland initiative and are anxiously awaiting the outcomes. The results of this study will hopefully provide a detailed blueprint for resolving this ecological catastrophe. The national and international significance of this effort prompted Congress to pass legislation supporting implementation of the project. President Clinton signed PL 105 322 into law on October 30, 1998 (9).
The value of trapping and leghold (foothold) traps in this venture cannot be overstated. The success of this project, and the future health of Chesapeake Bay wetlands, hinges to a large extent on these tools. They are undoubtedly the most environmentally sound techniques available to combat this ecological scourge.
C. Wildlife Disease Control
Although disease normally occurs in all wildlife populations, stress resulting from increased population densities may precipitate or confound the occurrence of disease infestations (10). Non regulated furbearer populations can function as disease/parasite reservoirs that pose a continual threat to humans, and also decrease the viability of wildlife populations. Furbearers are the primary vectors for numerous threatening maladies including rabies, giardias, distemper, tularemia, and mange. While trapping may not prevent the onset of these afflictions, it can reduce furbearer population densities. This may result in a reduction in disease transmission and reduce the intensity of further disease outbreaks (1).
Wildlife biologists and wildlife health care professionals have long recognized the integral role of trapping and foothold traps in the control and/or abatement of wildlife disease. Dr. Victor Nettles affirms this in the following statement: "Our main concern at Southeastern Cooperative Wildlife Disease Study is the importance of trapping as a wildlife management tool to deal with health concerns. Under the guidance of professional wildlife biologists, trapping can be the most effective method to maintain some furbearers at optimum population densities. As a result, animals remain in good physical condition, and risk of devastating disease outbreaks is diminished. The reverse is true of some unmanaged populations, where depletion of food supplies due to overpopulation results in declining physical condition. Animals are thus predisposed to increased transmission of disease and parasites. When wildlife are permitted to overpopulate, the net result is weak, pitiful animals that cannot defend themselves or care for their young” (4).
D. Animal Damage Control
As human and furbearer population densities increase, the relative probability of negative interactions also escalates proportionately. Historically, the majority of wildlife complaints attributed to furbearers have been borne by rural residents. These conflicts typically impact agricultural producers and can result in substantial economic losses from livestock and crop depredations. Understandably, extensive attitudinal and public opinion studies document strong support for trapping and the use of leghold (foothold) traps by rural inhabitants and agricultural producers (11). Locally, the Maryland Farm Bureau has issued a policy statement supporting the continuance of regulated trapping. Although these types of interactions tend to define furbearer complaints, shifting human demographic patterns are changing the complexion of many furbearer management issues.
While encroaching suburban sprawl has eliminated and/or fragmented wildlife habitat, many furbearer species have proven extremely resilient and now flourish in close proximity to dense human habitation. Prey species, den sites, etc. may become substantially altered in suburban and urban environments, but basic behavioral traits still fall within genetically predetermined boundaries. Coyote depredations quickly switch from sheep and cattle, to dogs and cats. Fox pursue cats instead of chickens, and raccoons raid garbage cans and pet feeders instead of sweet corn fields. Beaver continue to fell trees and dam bodies of water. However, they are now flooding septic systems and destroying ornamental trees in planned communities instead of impacting farmland and commercial forests. Similarly, preferred densities for raccoons now include attics and chimneys as well as hollow trees and rocky outcrops.
Aesthetically, most people enjoy viewing wildlife safely from a distance, and in “wild” areas. Nevertheless, these symbolic attitudes and tolerance levels quickly change when wildlife behavior deviates from the 'idealistic' norm. The public clearly supports trapping to address nuisance furbearer situations (11). In Maryland, the USDA Nuisance Animal Hotline alone has received over 11,500 complaints attributed to furbearers during its first 11 years of operation.
The economic ramifications of furbearer damage are well documented. Specific examples are as follows: In FY 2000, calf and lamb losses to predators in the US were estimated to exceed $70 million (12). As of 1999, more than 6 million tax dollars was spent annually to address coyote damage. In the absence of trapping, it was projected that coyote populations in the southeastern US (including Maryland) will increase by 210% during the following 10 years (13).
Beaver accounted for an estimated $109,279,000 in annual property damages and losses in the US (11). In the southeast, public employees expend more than 211,000 man-hours annually responding to beaver complaints. In the absence of trapping, it was projected that these beaver populations will increase by 110% during the next ten years (13).
Raccoons were responsible for an annual estimated $41,732,000 in damage in the US in 1999 (11). It was estimated that raccoon populations in the northeast would increase by 100% during the following ten years if trapping were prohibited (13).
The Importance of Trapping in Furbearer Management Strategies
Trapping furnishes the structural foundation for many DNR initiatives. Regulated trapping can accomplish prescribed management practices established by DNR to achieve vital furbearer management objectives. The occupied range and densities of furbearer species in Maryland requires a substantial statewide trapping effort to manage. Trappers function as DNR's unpaid technicians in the implementation of structured management strategies. In many locations across the state, nuisance wildlife control operators use traps to remove nuisance and unwanted animals from around human occupied areas. Without this highly trained community of interest, fiscal and manpower constraints would prohibit DNR from fulfilling many natural resources stewardship mandates.
In addition to overall population efforts, regulated trappers in Maryland have used leghold (foothold) traps to aid DNR in research projects, species reintroductions, threatened and endangered species restoration, ecosystem protection, nuisance animal damage abatement, and public health and safety issues.
- Organ, J. F., et. al. 1996. Trapping and Furbearer Management: Perspectives From the Northeast. Northeast Furbearer Resources Technical Committee. 33 pp.
- Boggess, E. K. 1990. Traps, Trapping, and Furbearer management. Wildlife Society Technical Review. 90-1. 31 pp.
- International Association of Fish and Wildlife Agencies. Resolution No. 1. Traps, Trapping and Furbearer Management. 2 pp.
- Nettles, V. F. May 2000. Personal Correspondence. Southeastern Cooperative Wildlife Disease Study. 3 pp.
- International Union for Conservation of Nature and Natural Resources. October 1993. Survival Service Commission. World Recovery Group. Resolution. 1 pp.
- Linscombe, G., et. al. 1997. Improving Animal Welfare in U.S. Trapping Programs: Process, Recommendations and Summaries of Existing Data. International Association of Fish and Wildlife Agencies. 60 pp.
- International Association of Fish and Wildlife Agencies. April 2000. Fur Resources Technical Subcommittee. Unpublished Data.
- International Association of Fish and Wildlife Agencies. 1999. Furbearer Resources Technical Work Group. Case Studies, Kiss the Babies Hello. 3 pp.
- Colona, R. C. 1999. Game Program Annual Report 1998-1999. Maryland Department of Natural Resources. 50 pp.
- Addison, E. M. 1987. Diseases and Parasites of Furbearers in Wild Furbearer Management and Conservation in North America. Pp 893-909.
- Fleishman-Hillard, Inc. 1999. Human Dimensions of Trapping and Furbearer Management. A report to the International Association of Fish and Wildlife Agencies’ Fur Resources Technical Subcommittee. Fleishman-Hillard Research. 114 pp.
- GAO Report. 2001. Wildlife Services Program: Information on Activities to Manage Wildlife Damage. GAO-02-138. 60 pp.
- Kenyon, S., et. al. 1999. Bears in the Backyard, Deer in the Driveway. Report Prepared by Southwick Associates for the International Association of Fish and Wildlife Agencies. 24 pp.