Hog Wild in Parks

November 1, 2013, Feature, by Richard J. Dolesh

Across the United States, many types of human-wildlife conflicts are increasing in areas where nuisance wildlife numbers are expanding. Illustration: Jeff Byrd.People love wildlife, and wildlife love parks. But what happens when natural systems in parks become unbalanced and wildlife becomes a problem for humans?

Wildlife can cause problems for humans that range from minor annoyances to truly dangerous situations for human health and safety. Species that become a “nuisance” are just what the term implies: They cause inconveniences or problems to humans, but they don’t rise to the level of significant economic damage or dangers to human health. Because of their adaptability, nuisance species can flourish in a wide variety of habitats and thrive on many food sources. When they live in close proximity to man, their behavior can cause major aggravation for humans.

For example, native wildlife in parks that are fed by humans, such as resident Canada geese or mallard ducks, can become totally dependent on the handouts and will congregate in numbers far beyond what their habitat will support. Other adaptable animal species, such as white-tailed deer, can eat a wide variety of foods and can exploit new habitat niches even in close proximity to humans. Some species that have high reproductive rates and few population controls from predators can quickly reproduce beyond the ability of natural habitats to support them.

Deer, wild pigs and other species can succeed precisely because new habitats and new food sources have been created by man’s activities. Other wildlife species, like beavers, can become harmful to humans when their activity impacts roads, bridges and developed infrastructure. Finally, some species, such as Canada geese, become a nuisance or even a health hazard from the waste they deposit, or because they can be a vector for diseases that are harmful to humans.

No matter what the reason, those species of wildlife that cause human-wildlife conflicts can suddenly become a huge problem for park and recreation agencies when their activities affect the public. So, what are managers of parks, public spaces and recreation resources to do when wildlife becomes a problem?

Human-Wildlife Conflicts in Public Parks

Across the United States, many types of human-wildlife conflicts are increasing in areas where nuisance wildlife numbers are expanding. Reasons include loss of suitable wildlife habitat, the growth of human and animal populations, and human-caused changes to natural environments that increase the chances for conflict.

Nuisance wildlife species may be native or exotic; their problem quotient depends more on where they are located and what they do in relation to human activity than where they came from. In fact, many of the most prevalent nuisance species in parks are native. Sandy Spencer, supervisory research biologist at Patuxent Research Refuge in Laurel, Maryland, says, “Any wildlife species has the potential to become a nuisance to man — it all depends on their location and numbers, and what the human priorities are.”

Some of the most common species that become a nuisance in parks are resident Canada geese, white-tailed deer, beavers and wild pigs. Other animal species, such as seagulls, ground squirrels, coyotes, alligators, bear, nutria and muskrats may be nuisances locally, but due to their limited range or habitat requirements, they don’t rise to national prominence. Ironically, the restoration of some of these species to their former ranges across North America is considered a conservation success story.

White-Tailed Deer

At the turn of the 20th century, conservationists feared that white-tailed deer could become extinct from overhunting. Strong conservation efforts brought the species back, and the gradual changes to landscapes in their range, such as the clearing of forests, the expansion of agricultural lands and creation of more edge habitat from residential development, have created a greater food supply and expanded the range for the species. These factors combined with population management for hunting have caused an extraordinary growth in the population of deer. The U.S. Department of Agriculture (USDA) now estimates that there are more than 30 million deer in the continental U.S., the highest number of deer ever recorded. And deer have become more than a nuisance in some areas of the country, reportedly causing nearly $1 billion in crop damage and more than $4 billion in damage from deer-vehicle collisions each year.

Overabundance of deer can actually cause large-scale changes to ecosystems as well, including significant damage to forest health from extensive browsing and loss of ground plants and nesting areas for birds, amphibians and mammals. Kelli Kovacevic, superintendent of natural resources management for the Morris County Park Commission in New Jersey, says, “The largest impact from deer that we are trying to mitigate is damage to forest health. Many of our forests have little to no understory left because deer are consuming the native plants that are within reach to such an extent that many species are no longer regenerating. The lack of native plants facilitates the establishment of invasive species, which are an enormous problem in all of our parks.” Other park and recreation systems report significant losses to landscaping, floral gardens and demonstration farms. Some park and recreation agencies have reported increased incidence of deer-vehicle collisions because of overconcentrations of deer in park areas near public highways.

Practical control measures for deer are somewhat limited due to the range and habits of this species. Fencing of arboretums, horticultural gardens and native forests is expensive and not practical for large areas. In addition, the exceptional adaptability of deer allows them to browse a huge range of plant species for food. When park managers and naturalists see their supposedly “deer-proof” plantings chewed down to nubs, they recognize that they have a problem much bigger than they can control.

Many park agencies instituted deer-control measures years ago when exploding populations of deer began to destroy the integrity of forests and woodlands. John Watts, resource manager for Columbus and Franklin County Metro Parks in central Ohio, says, “Some of our parks had concentrations of 400 to 450 per square mile.” Deer biologists say that concentrations of deer at 40 to 50 per square mile can be considered overpopulated and can cause damage to natural ecosystems. Watts described the development of a management program that first started with gathering data, engaging the public, and employing a variety of control methods including deer contraceptives, culling, managed public hunts and continuous public education. He says, “After our years of experience, it is clear that there is no one answer that solves all problems or applies to every situation. We found that we needed to keep all options on the table, and that seems to work.”


Who doesn’t love these large, endearing, semi-aquatic rodents with giant teeth? Beavers build intricate marvels of natural engineering and create acres of valuable new habitat for wildlife. What’s not to like about them? Plenty, if you ask highway engineers, landscape designers, golf course superintendents and park managers.

Beavers are remarkable animals. They feed exclusively on plants, usually the inner bark of softwood tree species that they cut down, and store caches underwater for their winter food supply. They also build dams on the headwaters of streams for one primary purpose — to submerge the underwater entrance to their lodges.

Beavers were once widespread through North America, but trapping nearly extirpated this species from its entire range. They have made a significant comeback in most areas of their historic range in the last 50 years, sometimes to the point of overpopulation, causing no amount of consternation to park managers and public works employees.

Beavers are one wildlife species in which creative management solutions can sometimes work. When biologists observed that the primary stimulus that caused beavers to build dams was the sound of running water, they devised ingenious pond levelers and water-control structures that allow water to drain almost silently in normal flow conditions. The beavers no longer hear running water, and as a result, they cease or slow construction of their dams.

When beavers have filled their available habitat, they will resort to living in areas undesirable to man, such as highway drainage culverts, roadway crossings or golf courses. Live trapping and relocating beavers is usually not a viable solution for control for a number of reasons, including state and local laws prohibiting transportation of these and other furbearers.

Canada Geese

“Resident” Canada geese, as distinguished from migratory Canada geese, have only become a nuisance wildlife problem in recent decades. Once a beloved wildlife species, Canada geese numbers were greatly reduced by overly permissive hunting laws and other factors, and the populations in the major flyways were reduced to much smaller wintering flocks. Dale Humburg, chief scientist for Ducks Unlimited, says, “Efforts to restore historic populations of Canada geese began in the ‘60s and ‘70s. Giant Canada geese had almost become extinct as a subspecies.”

State natural resources agencies actively tried to reintroduce them within their historic wintering range by trapping and translocating them to parks, agricultural ponds, rivers and lakes. Here, geese benefited from the lack of predators, abundant local food supply and congenial climes. They bred very successfully, and then, not having the ancestral knowledge of how to fly home, no longer migrated back to Canada each spring. They are now year-round species throughout every flyway. “Wherever they wound up, especially in a park, people really enjoyed them,” Humburg says. “They had no idea of the potential problem that would develop.”

Today, there are about 4 million resident Canada geese in the U.S., grown from a population of about 250,000 in the 1970s. Resident geese are particularly prevalent on golf courses, beaches, ponds, lakes, rivers, and open areas of public and business parks. Although beautiful creatures, each adult Canada goose deposits about one pound of feces per day, which causes no end to problems for stewards of public space. While the physical “leave-behinds” are objectionable enough, greater issues arise from enrichment of nearby waters from nutrient pollution and the potential threat of disease transmission from E. coli bacteria and other pathogens.

To compound the problem, geese are prolific and successful breeders. Both parents defend the nest and protect their young. Egg oiling and egg addling are effective for future population control, but these methods will not reduce existing populations. Deterrents rarely work for any length of time, even active deterrents such as pyrotechnics, predator decoys, harassment and other methods. One nonlethal form of control that does work is the consistent use of sheep-herding dogs, such as border collies, but only when they are employed on a daily basis.

The Chicago Park District (CPD) uses border collies as part of a comprehensive program to deter geese and seagulls from its 26 miles of Lake Michigan shoreline. The collies do an excellent job and are well-supported by the public, but the annual cost for CPD may approach $100,000 for dawn-to-dark coverage by private contractors for the entire beach season. Some park and recreation agencies report good success with limited daily visits by trained dogs at a cost of around $10,000 for the season.

Wild Pigs

“The whole state is under siege!” says Valerie Carter, resource management biologist for South Carolina State Parks. “There are now approximately 150,000 feral pigs statewide, and they are even starting to impact cultural and historic resources.” Hampton State Park, one of South Carolina’s most important state park historic sites, is ground zero in the efforts to halt the depredations of wild pigs that are destroying subsurface archeological and cultural resources by rooting behavior.

The populations of wild pigs, also called feral swine or wild boar, are growing explosively throughout the South, the Southwest, the West and now the Midwest. The USDA now estimates that there are more than 5 million wild pigs in the U.S., 3 million in Texas alone, and they are expanding their range dramatically. In a New York Times article, Ed Reed, a wildlife biologist for the New York state Department of Environmental Conservation, said, “They eat everything. They’ll eat the understory in a forest and dig up plants by rooting the ground for insects and roots. They compete with wildlife for food. They’re the most destructive mammal out there.” Park managers are especially concerned about dealing with wild pigs in park settings because the public often doesn’t realize the danger they can be to children and adults.

Managing the Public

If there is one solid lesson to learn from wildlife-management professionals for dealing with nuisance wildlife, it’s that the root of many wildlife conflicts is human behavior. This proves true not only in trying to educate the public on why they shouldn’t feed wildlife, but also for gaining understanding and acceptance of management and control actions that need to be taken to address human-wildlife conflicts. “It takes a lot to educate the public about cause and effect, but you must invest the time and effort,” says Jennifer Schaeffer, government affairs director for the Association of Fish and Wildlife Agencies (AFWA). 

A number of park and recreation agencies are either reluctant to enforce no-feeding ordinances or intimidated by pushback from the public, media or elected officials. Dave Mizejewski, naturalist for the National Wildlife Federation, says, “People love wildlife — it is part of why they love parks. When there are human-animal conflicts, education is the key. I can’t overstate the importance of education, and that is our job. We can funnel and channel the passion that people have into appropriate ways to respond.”

Cathy Breitenbach, director of lakefront operations with CPD, concurs. “Most people we have dealt with have no idea there is a connection between feeding the birds and water quality,” she says. “Once they learn what the impacts are, they are very willing to take action to change their behavior.”

Taking Action

Dealing with nuisance wildlife takes sustained collective effort, and your partnership must include all stakeholders, even those who might be opposed to the actions you may want to take. Humburg says, “Have all the methods on the table, and bring all stakeholders together. Try to achieve broad agreement among all interests. Consider every possible course of action and look at all possible solutions. Be willing to adapt as you learn, and anticipate the potential for additional problems as you work toward solutions.” 

Trapping and translocating nuisance wildlife is rarely a good solution. Not only are there not many suitable places for such wildlife, but state and local laws often prohibit the transport of such species. In the most difficult decisions dealing with nuisance wildlife, public park and recreation agencies should consider lethal control measures for nuisance wildlife only as a last resort. There are very few cases regarding nuisance wildlife in parks that truly warrant the taking of wild animals, and unless there are compelling public safety or public health reasons to resort to such measures, it is better to expend every effort to seek nonlethal solutions. This may reasonably involve considerable resources and time to modify environments, utilize deterrents, establish control measures, change human behavior, educate the public and find sustainable long-term solutions to coexist with wildlife. Yes, this course of action requires time, resources and patience, but it will prove to pay dividends in the long run. However, there are cases involving legitimate public and wildlife health issues or public safety concerns about wildlife, and there may be no other good alternatives. USDA Wildlife Services and state natural resource agency personnel are the best-equipped to advise if such situations develop.

Partnerships with conservation and humane animal care organizations are valuable in engaging the public, gaining public consensus, and in some cases providing volunteers for monitoring and even some management activities. Their participation will also ensure you have broad concurrence for actions you may wish to take.

It’s the Law

When confronting wildlife problems, park managers need to know that most native and even most invasive wildlife species are protected by law and regulation. You must be fully knowledgeable of the requirements of the law before attempting any control measures.

Park and recreation professionals can get information and guidance on law and regulations from the following sources, as suggested by wildlife subject experts at the USDA’s Office of Wildlife Services:

In general, native mammals are managed by the state wildlife agency, such as the department of natural resources. 

In general, native birds are managed by the U.S. Fish and Wildlife Service (USFWS) in the Department of the Interior. European starling, sparrows, pigeons and mute swans are not native birds and are not managed by USFWS. Some states do have rules regarding these birds, and USDA Wildlife Services can offer state-specific guidance.

The best course of action when presented with human-wildlife conflicts and damage is to call USDA Wildlife Services at 866.4USDA.WS (866.487.3297) or visit the program's website to reach the office in your own state. The USDA’s Wildlife Services program staff have good knowledge of and relationships with other agencies that manage the wildlife itself. Private wildlife control cooperators can help agencies that don’t have the knowledge or capacity to deal with wildlife problems.

Appropriately dealing with nuisance wildlife is a complex issue with different contributing factors for every situation, but there are ways to ethically deal with the needs of the wildlife in your jurisdiction as well as the perceptions of the public you serve.

Says Watts, “If it was just a question of wildlife control, solutions would be easy. However, there is a social value to wildlife in parks, and as managers of parks and wildlife, we must respect that. We have to understand that everyone has an opinion and places value on wildlife.”

For an extensive listing of contacts and resources for how to deal with nuisance wildlife, including outreach to private wildlife cooperators and contractors, visit www.parksandrecreation.org/2013/November/Hog-Wild-in-Parks.

Richard J. Dolesh is NRPA’s Vice President of Conservation and Parks.


Got Conflicts?  Here are Resources for Help

State-by-state list of state natural resource, fish, and wildlife agencies 

Federal government agency that provides technical assistance and support to local government and private property owners: U.S. Department of Agriculture, Wildlife Services (APHIS): USDA Wildlife Services at 866.4USDA.WS (866.487.3297)

State members of the National Animal Control Association. For state and local animal control offices responsible for dealing with wild animals, dangerous animals and confirming animal bites, contact your local municipal or county government listings.  

Private sector organizations providing wildlife control services to local governments:

  • National Wildlife Control Operators Association, NWCOA Executive Office, P.O. Box 655, Fredericksburg, VA 22404. 855.GO.NWCOA (855.466.9262), 540.374.5600
  • National Pest Management Association, 10460 North St., Fairfax, VA 22030. Phone: 703.352.6762, Fax: 703.352.3031, Email: NPMATeam@vaultcommunications.com (Consumers and Media) 
    jrickwalder@pestworld.org (Members).

Some info resources for managing conflicts with specific wildlife species:

  • DeNicola, A.J., K.C. VerCauteren, P.D. Curtis, and S.E. Hygnstrom. 2000. Managing white-tailed deer in suburban environments: a technical guide. Cornell Cooperative Extension. 56 pp. (currently being revised)
  • Exemplary info on deer history, biology, forest health, and deer management:  https://www.dcnr.pa.gov/Recreation/WhatToDo/Hunting/Pages/default.aspx