Yes, I'm curious too where they learned the behavior. It may be that they taught themselves. That is, they may have gotten used to garbage and will now pursue human food wherever they smell it, even if it means breaking in. I had bears take out all the downstairs screens in the house one night ten years ago when bread was baking inside. Ever since, at night, I never leave the windows open more than a foot high. The trend for bears to "go urban" and live on garbage is spreading quickly, and it's easy to see why: the average "urban" bear spends 8.5 hours a day feeding as opposed to the average wild bear, who has to put in 13 hours a day to feed itself. The urban bear is doing better scoring on calories, too, as its average weight is greater. Yesterday's NYT Science section had an interesting piece on urban v. wild bears. The article starts out talking about the west but shifts to the ADKs. Looks like they got it wrong, though, about urban bears in NJ.
NYT Science Section
June 7, 2005
With Carryout, Bears Find a Life-Changing Experience
By CORNELIA DEAN
Until recently, the black bears in the Nevada mountains had a hard life. Housing developments, ski resorts and golf courses were moving into their habitat. In dry years, finding protein-rich pinyon nuts, a staple of their prehibernation diet, could be a challenge. Often, the berry patches produced thin fruit crops.
About 10 years ago, though, the bears discovered a source of food that is widely available, regularly replenished and nutritious. They discovered garbage. And they have moved en masse into urban areas to enjoy it.
"Garbage is the ultimate resource for bears," said Dr. Jon P. Beckmann, who studied the black bears of western Nevada for his doctoral dissertation and now works in the mountain West as a field ecologist for the Wildlife Conservation Society, the organization that manages the Bronx Zoo.
Garbage is richer in calories than nuts or berries, he said, and it is much easier to find, turning up regularly in the trash bins and garbage cans of every subdivision. And unlike a berry patch that produces fruit only once a year, the trash bins are like a chain of luncheonettes for bears that never run out of food. Bears that live on garbage are heavier and taller than their country cousins, Dr. Beckmann said. They even have more cubs.
In the early 1990's, 90 percent of the region's bears were living in the wild and 10 percent were urban, Dr. Beckmann said. But drought in the late 1980's and early 1990's sent bears to towns in search of food, and today 90 percent of the region's bears are urban, with some living full time inside city limits or even in single neighborhoods.
"Once they discover garbage, they don't look back," he said.
Dr. Beckmann said the shift was unusually pronounced in the Nevada mountains he studied because the contrast was so great between the sparse forage of the hills and the abundance of the bins. But similar problems are cropping up all over the mountain West and other locales where bears and people come into contact.
Dr. Beckmann, who described his research in a talk last month at the zoo, came East to describe bear-control efforts to wildlife managers and other officials in the Adirondacks, which has its own nuisance bears.
"There has been a huge increase in bear incidents in the high peaks," said Bill Weber, director of the Wildlife Conservation Society's North America Program, referring to the 46 mountains south of Lake Placid and Saranac Lake that are more than 4,000 feet high. In part, he said, the increase is attributable to more building in areas open to development there.
The New York State Department of Environmental Conservation has proposed changing rules in wilderness areas of the Adirondack Park to require visitors to keep food, garbage and toiletries in containers "manufactured for the specific purpose of resisting entry by bears." To be bearproof, Dr. Beckmann said, a container must be made of thick, nonpliable metal, and have latches in recessed compartments bear paws cannot reach.
In New Jersey and Connecticut, where the black bears were almost wiped out by 1900, populations are also on the rise. So far, urbanized bears are not a big problem in those states, but wildlife agencies nevertheless advise rural residents to invest in bearproof garbage containers; to store garbage in garages, sheds or basements; to make sure the grill is cleaned after every barbecue; and to otherwise avoid tempting bears with food.
Requiring bearproof containers is one of the few effective measures for getting rid of nuisance bears, Dr. Beckmann said, noting that when he and others captured Nevada bears and moved them far out of town, even hundreds of miles away, 92 percent returned, 70 percent in less than 40 days.
At Yellowstone, where he is working now, nuisance bears dispersed into the woods after the widespread adoption of bearproof trash bins. But naturalists are beginning to wonder whether urban living has changed bear habits so much they will have a hard time readjusting to the wild. Dr. Beckmann, who used radio collars and other means to identify and track bears, said bears in the wild were typically active 13 hours a day, in daytime, hunting for food. The urban bears were on the move only about 8½ hours and at night, "cruising through the garbage under cover of darkness."
Abundant food and relative lack of exercise may explain why urban bears are so much larger than their rural cousins. In the wild, males rarely weigh more than 250 pounds, but garbage-fed males routinely reach 400 pounds or more.
And while the rural bears retire to their dens for winter on Dec. 4, on average, the urban bears put it off until New Year's. "We had several male bears giving up on hibernation entirely," Dr. Beckmann said.
Although there are occasional reports of black bears attacking or even killing people, these incidents are rare, Dr. Beckmann said. Even attacks on livestock are unusual. But when bears are kept out of garbage cans or trash bins, they sometimes turn to cars and houses.
Black bear claws are shorter and more curved than the claws of the larger brown bears, Dr. Beckmann said, which makes them ideal for ripping open a car door, tearing a kitchen window out of its frame or clawing through siding.
He can cite many examples of bears breaking into kitchens and overturning refrigerators, napping in people's hallways after ransacking their pantries or otherwise terrorizing householders.
That is just one reason naturalists hope that bears will eventually give up the bright lights and return to their wild roots. In spite of the urban abundance of food, and the fact that urban females have on average 2¼ cubs per litter, compared with 1½ for rural bears, the overall bear population is not increasing, Dr. Beckmann said, probably because so many urban bears are killed by cars and trucks. Also, bears living in towns do not perform the ecological tasks - like seed dispersal or insect-eating - they would normally perform in the wild.
But given the sprawling growth in places like Nevada, bears do not have to move to town to find themselves urbanized. "We had a bear that had 400 homes go up right in the middle of its home range," Dr. Beckmann said. "Now it spends its entire time within those 400 homes."
