Dear deer are a nuisance

“Put your chest on the deer. Reach out and hold the legs. Never let go of the hooves.” Bill McShea, a wildlife biologist at the National Zoo in Washington, D.C., is instructing a handful of assistants in the art of subduing a wild white-tailed deer.

The researchers are in Virginia’s Blue Ridge Mountains on a warm morning. The night before, the group had sprinkled a trail of alfalfa pellets into five deer traps, wooden boxes about 5-feet tall with doors that fall shut when a deer steps inside and trips a string. This animal went for the bait.

McShea and co-workers guide the deer through a door in the trap into a smaller box, then pull the squirming nearly 100-pound animal out by its hind legs. Two people pin it to the ground, and each grabs a set of kicking legs. Another helper covers its eyes with a dark towel.

“That’ll take 90 percent of the fight out of the deer,” says McShea. The animal is female, so McShea reaches for a syringe and injects her in the rump.

The syringe contains an experimental contraceptive drug. McShea and others are testing, first, whether it will reliably block a doe’s reproductive cycle for life and, second, whether birth control drugs could possibly make a dent in America’s deer population boom. When it comes to controlling deer populations, McShea tells Smithsonian magazine, “You want to have as many tools as possible.”

Once overhunted, white-tailed deer have returned in such explosive numbers that they’re ravaging forestland and besieging rural and even suburban communities. The animals cause car accidents, carry ticks that can transmit infectious diseases to people, chew up landscaping and otherwise make pests of themselves, albeit sometimes strikingly graceful ones.

Deer numbers are rising in part because their traditional predators, including mountain lions and gray wolves, were eliminated from most Eastern forests long ago. Also, white-tailed deer reproduce quickly – a female has one to three fawns each year – and they’re one of the more adaptable species around, living from subarctic to tropical climates. Past restrictions on deer hunting have also fueled the boom.

But deer are also thriving because of the ways people have carved up the countryside, unwittingly creating prime deer habitat.

Deer, says McShea, are an “edge species,” meaning they thrive where forests meet fields. They seek shelter in forests, but most forest food is too high for them to reach. Edges abound in plants deer can munch.

“Originally, the eastern United States was one deep, dark forest,” McShea says. “Now it’s deer nirvana. It’s one big edge.”

Nationwide, cars hit at least 1.5 million deer a year, the Insurance Institute for Highway Safety reports, causing more than a billion dollars in vehicle damage. In 2003, collisions with animals killed 210 people, and three-quarters of the encounters involved deer.

Deer transport ticks that carry Lyme disease; more than 21,000 cases were reported in 2003.

Deer browsing transforms forest ecology too. For the first time in its 108-year history, the New Jersey Audubon Society recommended hunting in its sanctuaries as a wildlife-management strategy. But in many areas, including almost all suburbs, shooting deer is both unpopular and illegal – which is why deer contraception may be an idea whose time has come.

At the 3,200-acre campus of the National Zoo’s Conservation and Research Center near Front Royal, Va., McShea has been overseeing a study of immunocontraception, or using a vaccine to prompt the animal’s immune system to prevent conception. Since 2003 he has been testing a Canadian PZP-derived drug called SpayVac, which costs $110 per dose but may last a deer’s lifetime.

The drugs aren’t perfect. Not even reliable contraceptives can, by themselves, solve the problem. Before the SpayVac tests began in 2003, McShea had 232 deer culled from his 850-acre experimental area, leaving about 50 deer behind. Now the population in that area is growing, despite contraceptives, because new deer are immigrating to the property. He says widespread hunting will be needed to reduce deer populations to a sustainable level.