Burgeoning populations of wild animals in cities and suburbs throughout the country may thrill folks who rarely, if ever, see such creatures outside a zoo or museum, but these animals can wreak havoc on human health and safety.

Wildlife experts say that human activities, as well as groups that oppose culling troublesome animals, are directly or indirectly responsible for many of the risks to people. To save life and limb, it pays to know what is out there and how to reduce the chances of hazardous encounters with wildlife in our midst.
At least six coyotes have found their way into New York City this year, including one that crossed the Hudson via the Holland Tunnel. The animals move easily into residential areas along travel corridors like greenways, power lines and train tracks, according to Paul D. Curtis, a wildlife specialist at Cornell University who studies human-wildlife interactions and ways to minimize their negative consequences.

Although coyotes are rarely a threat to people, Dr. Curtis said in an interview that they can be aggressive when breeding and rearing pups. In just the last week and a half, in separate instances, two young girls, ages 6 and 3, were attacked by coyotes in their Rye, N.Y., backyards. Small children have been attacked in Los Angeles and Arizona, Dr. Curtis said, and small dogs everywhere are at risk, even when on a leash.

In January 2009, a flock of Canada geese got sucked into the two jet engines of a loaded US Airways flight and forced an emergency landing in the Hudson, a stone’s throw from Manhattan. The resident population of urban and suburban geese has soared to more than 4 million of these 10-pound birds, each of which deposits a pound of slippery excrement a day, often on park paths, golf courses and athletic fields.

Raccoons, the most adaptable of urban wildlife, rummage through trash cans, snack on pet foods left outside and occasionally break into homes, where they can cause serious destruction in search of food.

The animals may bite when cornered. But their main risk to humans and pets is rabies. There are now rabid raccoons in many areas east of Ohio, including Central Park and Nassau County, where wildlife experts are studying novel ways to get them vaccinated.

White-tailed deer wander fearlessly into suburban yards and fields, munching on crops and ornamental plantings, spreading dreaded ticks that cause Lyme disease. A hungry deer consumes six to eight pounds of vegetation a day, often with little respect for lists of deer-resistant plants.

Deer kill far more people each year than do alligators, and cause over 1.5 million car accidents a year (more than 70,000 in New York State alone).
You need not have seen black bears roaming around Woodstock, N.Y., in April to know that they had ended their hibernation. Overturned garbage cans, with their nonedible contents strewn over lawns and roadsides, were a dead giveaway.

The animals are well established on the west side of the Hudson, where they have caused an occasional fatality. Get between a mother and her cub and you may become history.

The range of black bears has more than doubled along the entire southern border of New York State and across the Hudson in the last decade. “I don’t think black bears will come to New York City, but I’d never say never,” Dr. Curtis remarked.
Dos and Don’ts

Heading the list of negative human behaviors is feeding wild animals, directly or unintentionally. Providing food can cause them to lose their fear of people and bring potentially aggressive quick-footed creatures, like coyotes, bears and raccoons, much too close to potential prey, like children and pets.
Edible garbage should not be left outside in unsecured containers where bears and raccoons can forage. If you live near a city park, like Prospect Park in Brooklyn, and you find your trash can ravaged, chances are a raccoon was responsible. Garbage should be placed in metal cans with tight-fitting lids and enclosed in a bin or attached to a solid object.

In residential areas like Woodstock, the bears seem to know what night people put out their garbage for morning collection. They are capable of overturning almost any can except a bear-proof dumpster.
Composting food items is also a bad idea, unless it is done behind a fence that can keep out bears and raccoons. Otherwise, limit compost to nonfood items like leaves.
Pets should be fed indoors; never leave pet food outside. Dr. Curtis recommends taking down bird feeders in summer (bears love bird food) and picking up fruit that drops from trees.

Make sure your chimney has a cap; raccoons without a tree den will use chimneys to raise their young. You can keep out skunks by sealing off openings under porches, decks and crawl spaces.

Unless your property is surrounded by a tall fence, try planting only what deer dislike — plants that are bitter, pungent, toxic or prickly, like rosemary, chives, daffodils, boxwood, barberry, juniper and other evergreens (though a very hungry deer will eat almost anything). Keep bird feeders out of a deer’s reach.
Unless you have a large or aggressive dog that lives outdoors, vegetable gardens should be fenced to keep deer out. (Use chicken wire buried a foot below ground level to deter rabbits and small rodents.) Deer repellents do help, if sprayed often on vulnerable plants. I’ve had luck with a smelly (to deer, at least) fertilizer called Milorganite (made from human waste) sprinkled on the soil around ornamental plantings.

To reduce the ever-growing population of urban and suburban geese, biologists have demonstrated that removing the eggs and nests of locally breeding birds encourages them to find other residences more hospitable than local parks. Other control efforts, like harassing geese with border collies, firecrackers, remote-controlled boats, high-powered lasers and strobe lights, have not worked unless they were done daily, Dr. Curtis said.
Research is under way to control the spread of Lyme-carrying deer ticks. In heavily infested areas of New York State, like Shelter Island and Fire Island, corn-stocked feeding stations equipped with neck rollers treated with tick-killing chemicals have reduced the tick population by 70 to 90 percent, according to preliminary results. A similar tactic under study in Central Park — providing feed laced with rabies vaccine — appears to be effective in reducing this deadly hazard from city-dwelling raccoons.

Dr. Curtis urged prompt reporting of any raccoon acting abnormally, like foraging during the day, coming close to people or walking with an odd gait.
Localities that have experimented with culling deer and bears have demonstrated a significant reduction in motor vehicle accidents and fatalities caused by these animals. Hunting, the main deer-control technique of decades past, has declined greatly. However, states that encourage the killing of does have found that it can control the deer population better than the killing of bucks.

By JANE E. BRODY (NYT. July 5, 2010)