Bambi has Outgrown the Forest, and Alternatives for Control are Elusive, Inefficient or Unpleasant
By: Norma Bennett Woolf Date: 01/12/2012 Category: | Wildlife Journal |
t’s late afternoon at Big Meadow in Virginia’s Shenandoah National Park, and dozens of deer mosey along, nibbling on tender shoots and keeping wary eyes on people trekking across the open expanse or hiking along Rapidan Road. Get too close and they subtly shift direction, but there’s no panic, no flagging of white tails to signal danger: they just go browsing along.
Thirty years ago, hikers and horseback riders were fortunate to see a white-tail in the park; today, it is a rare hiker who leaves the park without having his path crossed by Odocoileus virginianus.
Shenandoah is not an aberration: white-tailed deer are overwhelming their habitat in state after state. Pennsylvania, Michigan, Ohio, Maryland, New Jersey, Wisconsin, New York, Massachusetts, and other states are grappling with awesome numbers of deer that are causing vehicle collisions, destroying native plants, eating farm crops, and feasting on expensive landscaping.
Hamilton County, Ohio, is coping with up to 200 deer per square mile in parks that can support about one-tenth that number. At its November 7, 2002, meeting, the park board voted to hire sharpshooters to cull deer from three parks that are severely impacted, a plan supported by the Hamilton County SPCA and the Cincinnati Nature Center as the most humane option available.
The Maryland Legislature passed a deer management bill this year to aid in dealing with its estimated quarter-million deer, but the governor vetoed the bill when weekend hikers complained.
Pennsylvania changed its hunting rules to allow more does to be killed because overpopulation of deer is causing serious damage to state forests.
A New Jersey court upheld the authority of cities to hire sharpshooters to cull excess deer in urban and suburban areas.
The US Department of Agriculture reported that more than one million deer-auto collisions take place each year with more than 29,000 human injuries and estimated vehicle repair costs of more than $1 billion.
There’s no doubt that people love to see the beautiful and graceful white-tailed deer in parks and green spaces along country roads and highways. There’s also no doubt that the deer have used human development as a springboard to population growth that is causing millions of dollars in crop damage, vehicle repairs, loss of human life and devastation of wildlife habitat.
Nature arms its animals with survival mechanisms, and deer have an overabundance. They have a high reproductive rate, browse and graze on a wide variety of plants, have keen senses of hearing and smell, and warn other deer of danger in the vicinity with their tail flags.
Humans have improved deer habitat by deliberately saving large tracts of land, as by-products of agriculture, and through a growing acceptance of urban and suburban planning schemes that provide green space in residential, commercial, and industrial zones. Farm fields provide a smorgasbord of crops and edge habitat – that blending of field and forest that deer prefer. City and suburban parks, state parks and recreation areas, and federal monument reserves provide protected areas where hunting is rare or forbidden altogether. Developers leave green space in residential, commercial, and industrial areas and public spaces; counties set aside land for parks and recreation; and organizations acquire land to develop urban nature centers and environmental education areas – and deer love it all.
Deer are ruminants, an order of hoofed mammals with an even number of toes on each foot and a chambered digestive system capable of converting plant matter to energy and muscle. They browse and graze on a wide variety of grasses, shrubs, wildflowers, saplings, bark, fruit, fungus, nuts, grains, legumes, and landscape plants, changing diet as the year progresses. They wear pathways through fields and woods and crush plants in their bedding spots.
A high rate of reproduction (30-40 percent is possible) keeps the population up, even in years when browse is scarce. Although deer generally wait until their second year to breed, some does are fertile in their first fall. The annual rut, or breeding season, occurs from October–December; most fawns are conceived by the end of November and born in May and June. From one to three fawns are born with the number dependent on doe age, nutrition level, and winter conditions. Scarce food supplies and high doe-to-buck ratios can cause the breeding season to lengthen and result in late-born fawns that may be too weak to make it through their first winter.
Vehicle accidents involving deer are highest during the rut as bucks stake out and defend territories and pursue does to breed.
Damage to orchards, crops, and landscaping and deer-auto accidents can be prevented or minimized with precautions and creativity, but many of these techniques simply shift the animals and the damage they cause to neighboring yards and farms.
Homeowners can erect eight-foot fences around their property, plant shrubs and flowers that deer don’t find tasty, and use deer repellants. However, fences are expensive and are forbidden in some residential developments, and deer will ignore repellants and change eating habits when driven by hunger.
Highway departments can place “deer crossing” signs in areas frequented by the animals, and communities can enforce laws that prohibit feeding of deer (especially near highways), and provide driver education information to help reduce collisions.
Deer whistles are promoted as a warning system to deer approaching the road, but the evidence that they work is skimpy. The Ohio State Police did not note a reduction in collisions with deer after installing the whistles on their vehicles, and university studies have failed to prove that the whistles are effective.
Most deer-auto collisions happen at night, so some highway departments have installed reflectors that are supposed to confuse deer when they are illuminated by vehicle headlights. These reflectors create a low-intensity light beam that bounces across roads, creating a moving light pattern that baffles deer and stops them from crossing.
Deer have few natural predators, especially in the eastern US. Fawns may be taken by bears or coyotes, but humans – hunters and drivers – are the major forces for population control.
Deer hunting is carefully regulated, but state biologists have changed tactics in recent years by expanding seasons and allowing more does to be shot. However, growing populations of deer in urban and suburban areas where discharge of firearms is not permitted and parks are crowded with visitors has led to research on alternative methods of reducing deer numbers, including the use of hired sharpshooters outside regular hunting seasons, testing of contraceptives and surgical sterilization, and capture and relocation projects.
Hunters continue to remove hundreds of thousands of deer from forests and farmland each year, but they generally prefer to shoot bucks for the trophy as well as the meat and hides. Although more and more doe permits are being issued, most hunters don’t want more than one or two deer for the freezer and many hunters can get into the field only a day or two during the season, so permission to kill several does doesn’t necessarily mean that the does will be killed. Gun hunting season in most states occurs in late November and December, when many does have already been bred, so removing bucks may have little impact on next year’s crop of fawns.
Sharpshooters work at night. They draw deer to bait stations in areas with natural barriers between the guns and any nearby development. They attempt to reduce the herd by a specific number of animals and donate the meat to charity food kitchens.
Immunocontraceptives (birth control) have been studied in recent years as an alternative to hunting, but they have limited effectiveness except in closed herds that do not have an exchange of animals over a large territory. The Humane Society of the US, an anti-hunting organization, has funded development and testing of contraceptive control, but so far the successes have been with isolated groups of animals such as the Fire Island population off the coast of Long Island, New York.
Although administration of contraceptives is considered a high-cost alternative to hunting or sharpshooting, the five year Fire Island project was relatively inexpensive – about 240 deer were darted and tagged for a total estimated budget of $40,000. However, the project depended heavily on volunteers, four of the five project leaders were paid by their universities, not out of project funds; residents provided lodging for the team members, and the Fire Island National Seashore office provided a vehicle.
Connecticut, Ohio, and Indiana are also experimenting with deer contraceptive projects in urban areas, but results are not yet available and there are no long-term studies of the effects of contraception on the animals.
An analysis of alternatives published by Cornell University in conjunction with a 1998-2001 deer population study in Cayuga Heights, New York, compared the use of immuno-contraception vaccines, surgical sterilization, use of abortive agents, bait and shoot plans, and a combination of bait and shot and sterilization.
The study determined that:
Use of immuno-contraceptive vaccines is time-consuming, labor-intensive and expensive. Success of this method depends on capture and immunization of 70 percent of the does in an area followed by annual boosters for all of these does. Cost was estimated at $1000 per doe for two years followed by the cost of darting in subsequent years. The advantage of the method was high public acceptance. The disadvantages noted were the substantial effort to capture, tag and treat does and to provide booster treatments in subsequent years; the potential for stray darts; the need to tag deer to warn that the meat might be tainted by hormones; and lack of an immediate population reduction.
Surgical sterilization (either tubal ligation or vasectomy) is 90 percent effective for the treated deer. This method requires capture of deer; removal to surgical site; capital equipment investment for surgery; and payment for veterinarians. Cost estimate was $200 per deer for the first 40 animals plus costs of equipment and veterinary services. Advantages of this slow, long-term population reduction method include public acceptance and one-time cost for the single capture and surgery.
Contragestation to cause abortion requires annual treatment with drugs delivered in bio-bullets. Annual cost was estimated at $300 per deer for bait and labor and capital costs for special guns to shoot bio-bullets. Disadvantages include a narrow window of treatment, negative public perception, the need for annual treatment of all does, and lack of an immediate population reduction.
Bait and shoot plans have low public acceptance but are cost effective and result in immediate population reduction. Cost was estimated at $300 per deer with possible extra expenses for additional law enforcement.
Combination bait and shoot plans to reduce herd followed by surgical sterilization of remaining animals to prevent future overpopulation results in immediate reduction in numbers but requires capital expenditures for sterilization equipment and veterinary services. Deer are also likely to be more wary following the bait and shoot portion of the program and therefore more difficult to locate and capture.
Relocation is not an option. Relocation areas are hard to find because overpopulation is a problem throughout the deer’s range, and darting and moving deer is stressful on the animals.
Reduction of the population to acceptable levels might be achievable if biologists and other scientists charged with making the decisions had the final say, but their efforts are being thwarted by activists who use emotional rhetoric, public demonstrations, and the courts to block any solutions that result in deer deaths.
Animal rights activists oppose hunting in any form, even if populations are out of control and are destroying habitat for other species. On one hand, they praise those who live in harmony with nature; on the other, they scorn the presence of humans in an environment they would reserve for animals. They want no development, even if that development encourages the presence of species that can live in harmony with man. They disregard the economic loss to farmers, plant nurseries, and homeowners when deer feast on crops, gardens, and landscaping and take little notice of the danger deer pose to motorists and the burden paid by insurance companies.
When local officials settle on a control method, activists claim that any solution that involves the death of deer is inhumane. City and suburban residents listen and react: decades of pleas to conserve land, media coverage of endangered species, and the joy of seeing wildlife all work in the radicals’ favor, giving them a platform from which to rally support for their no-kill option.
The anti-hunting group In Defense of Animals alleges that hunting, land mismanagement, and human encroachment on deer habitat have caused the conflicts between people and white-tails. They contend that deer-auto collisions occur because hunters chase deer onto roads, and claim hunting is ineffective as population control because reduced numbers of deer allow the habitat to recover and cause increased births to take advantage of increased food supply. They conveniently ignore the lack of undergrowth and seedlings in forests, the destruction of woodland wildflowers, the changes in dominant plant species, and the loss of nesting habitat for songbirds and ground-nesting game birds and cover for small mammals.
The IDA plan for reducing deer overpopulation is
- Ban sport hunting.
- Reintroduce natural predators, such as wolves and mountain lions, where possible. Maintain existing populations of natural predators.
- Ban clear-cut logging.
- Allow fires to burn naturally in wildlife areas. Limit new human habitations in wildlife areas, decreasing the risk of property damage in the event of a fire, and making controlled burns a more acceptable wildlife management tool.
- Prevent humans in residential areas, state parks, and federal parks from feeding deer. Deer should be reliant on their own habitat for food.
- Erect high fencing around crops and plants. Electric and sturdy fencing increase the effectiveness of this deterrent. Fences should be at least eight feet high and buried one foot deep. Openings in the fence should be small. Contact a university agricultural extension office or landscape business before purchasing and installing your fencing.
The IDA abhorrence of deer hunting is echoed by the HSUS, People for the Ethical Treatment of Animals, Fund for Animals, Friends of Animals, and many other national, state, and regional animal rights groups, and they are not reluctant to take the matter to court if local officials ignore their protests.
These groups embellish their arguments in opposition to hunting with claims of conspiracy between state agencies and hunters because fish and game budgets are greatly enhanced through a tax on hunting equipment and supplies. They ignore the high reproductive rate of deer and the ideal habitat created in and among cities and suburbs and instead assert that populations are high, in part, because state biologists have a financial stake in management systems that increase deer numbers so hunters will have more deer to kill.
The experts speak
Here’s how biologists describe the conflict between deer, people, and the environment:
The Minnesota Daily reported as follows on a university study of deer browsing in 1998.
“In some areas deer are changing the whole plant community and the tree community, too,” said Lee Frelich, director of the University of Minnesota Center for Hardwood Ecology and one of the authors of the study. The research, published in the latest edition of Conservation Biology, a national scientific journal, suggests that efforts to preserve natural areas will fail unless white-tailed deer populations are reduced by hunting or other means.
“Deer, Ecosystem Damage, and Sustaining Forest Resources,” a paper about Pennsylvania white-tail populations by deer specialist David S. deCalesta, concluded that, while hunters have a strong lobbying presence and bring about one billion dollars into state coffers each year, continued high densities of deer are detrimental to diversity in the state’s forests. Specifically, the report noted that
“Once deer density exceeded 10 per square mile, five songbird species were no longer observed on study sites. Abundance of songbirds declined when deer density exceeded 10 per square mile.” And “Species richness and abundance (expressed as percent of ground cover) of shrubs and herbaceous plants were significantly impacted when deer density exceeded 10 per square mile. Two shrub species and one herbaceous species disappeared when deer density exceeded 20 deer per square mile.”
A deer control measure was passed in the Maryland Legislature in 2002 with the following notes:
“As demonstrated by a 1998-1999 survey of Anne Arundel, Howard, Montgomery, and Prince George’s counties in which the number of deer in the areas studied increased by approximately 50 percent in the course of only one year, this population is not only thriving but reproducing at a startling rate.
“When a deer herd reaches its upper density limits, as is now the case, the results are the poor health and weakened physical condition of the animals and over-consumption of native plants, shrubs, and trees that are necessary for the survival of other species in the natural ecosystem.”
Maryland’s governor vetoed the bill because it opened the deer season to Sunday hunting. His veto message said in part: “Our outdoor resources should be shared fairly by everyone. Currently, Sunday during hunting season is the only day of the week when outdoor recreation such as hiking, picnicking, birdwatching, photography, angling, horseback riding, and other non-hunting activities can occur in the State’s natural areas without the fear of nearby hunting. Many naturalist societies routinely schedule nature field trips only on Sundays during hunting season to be certain they will avoid the interference and potential danger from hunting. I have received numerous letters from persons across Maryland opposing House Bill 9 because they would lose the certainty of having one weekend day during hunting season when their families and children can safely enjoy the outdoors.”
This fall, the Philadelphia Inquirer reported that “Deer have browsed their way through everything they can reach in Pennsylvania forests; anything green and less than five feet tall is, very often, simply gone. And that also threatens the birds and other animals that make their homes in the forests.
“At the end of hunting season last year, there were about 930,000 deer in the state’s forests, which was about 400,000 more than they can support.”
In late summer, the Haverhill Eagle-Tribune in Massachusetts reported “Deer population across the state was estimated at about 37,000 in 1984 and has been growing at rate of five to 10 percent a year, according to William J. Davis, a wildlife biologist for the Massachusetts Division of Fisheries and Wildlife. He said deer, fox and coyotes all thrive on development.
“‘People think that as we continue to develop, we squeeze wildlife out of the woods. But that’s not true with deer,’ Davis said. ‘They are among certain species of animal that absolutely thrive in suburbia. They do better in suburbia than they do in a similar size area of virgin woods. We’re actually making conditions better as we develop.’”
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All Authors Of This Article: | Norma Bennett Woolf |