WHEN Albuquerque, N.M., joined the list of Sun Belt cities that have grown by leaps and bounds in recent years, residents begrudgingly accepted the big-city problems they would have to face. But they never expected a bear invasion. Since Aug. 13, 21 black bears have wandered into the city's eastern outskirts. Some have been seen walking through shopping centers, across rooftops, and even falling into people's swimming pools, as they have been chased by New Mexico fish and game officials. Two have been killed by cars. One bear - presumably searching for her cub - climbed a utility pole, was injured, and was brought to the city's Rio Grande Zoo.
Mama Bear, as she is called, is now recovering well at the zoo. Her cub and another female bear are also being watched at the zoo. In addition, seven bears have been captured and trucked to northern New Mexico, where they were released in a more remote wilderness area.
Most people had no idea there were bears in the Sandia Mountains, just northeast of Albuquerque, a national forest containing the world's longest tramway. Recent upscale housing developments have pushed into the foothills of this mountain range.
Even state fish and game and National Forest Service officials say they have no clue how many bears live in the Sandias. They do know that berry and acorn crops failed this year because of a dry winter and early spring, depleting the black bears' main diet.
The bears are moving down the mountains to feed before hibernation, officials explain. So far, no bears have bothered household pets or foraged in people's garbage.
Residents of Albuquerque's Northeast Heights are worried about attacks from the bears. Some have suggested setting up a guard system or bear traps. But most people want to see the bears fed. Many have flooded the Animal Humane Association with donations for food. A television station offered use of its helicopter to make food drops in the Sandias. That plan brought an outcry from people who didn't like the idea of feeding bears dry dog food. Federal and state officials declared that no food could be dropped or backpacked in without a permit.
State game and fish officials brought in a bear biologist from Arizona to assess the problem. He explained that it was best not to feed the bears, to keep them from mating before they hibernate. Their instinct dictates that they put on certain weight before mating, and cubs normally are born during their mother's hibernation.
``They have the shelter and water they need,'' says Al LeCount, the bear expert. ``They will be able to den and make it through the winter, but this may not be the last time we see bears coming into the city if this winter is similar to last year's.''
Bears have always come down from the mountains when food supplies were scarce, he added. ``As Albuquerque keeps growing, if there's not some planning and zoning restrictions to keep people out of the bear habitat, we'll continue to have problems. Bears can't change. They're doing what they've always done,'' Mr. LeCount says.
Fish and game officials said they would only consider the problem serious once male bears came down from the mountains. The first 19 bears were females and two cubs - until Sept. 3, when a male arrived, followed by another the next day.
The Animal Humane Association now convinced state and federal officials to let them apply for a permit to leave food at the edge of the wilderness. The permit process, however, will take at least a month. Experts say the bears should start hibernating by mid-October.
``It's symbolic at this point,'' says Bill Mayhall, vice president of the Humane Association, ``whether feeding is going to hurt or help. Nobody knows. None of the experts even know how many bears are up there. That's what's so amazing. When you say experts, what are the federal people experts on?
``People want to do something; they've come in and offered their entire fruit crop, but it would spoil before we got it there. Dog food is the most feasible; a couple of experts have told us that would work,'' Mr. Mayhall says.
``But we've discovered this is a very bureaucratic world, even up in the wilderness,'' he added.
In southern New Mexico, several black bears have been moving out of the Capitan Mountains into farm areas, killing sheep. State officials, declaring that they have nowhere to move the bears, issued permits to kill them. Government hunters have killed 19 bears in the past two weeks, after bears reportedly killed 60 sheep.