BOULDER — AF69, a 90-pound female cougar, makes a healthy living on human habitat — stalking, eating and hiding deer around houses — usually when people aren’t looking.

But one day, while she was dragging a dead doe past a front door west of Boulder, homeowner Ian Morris caught AF69 on his camera — first as he peered through his screen door, then over two days as she cached her kill under grass clippings and periodically gorged.

“I wondered what she could see,” Morris said. “Could she see me? Would that be a good thing? We’re told that we should avoid any contact, which will make the animal more confident in approaching humans.”

He notified the Colorado Division of Parks and Wildlife, and wildlife researcher Mat Alldredge came and darted the cougar. Now AF69 is being tracked, along with 61 others, as part of a study that finds cougars may be living much closer to people than previously believed.

State researchers say AF69’s adaptive lifestyle, including regular night forays into the western edge of Boulder, reflects an emerging pattern for many of Colorado’s estimated 3,500 cougars. GPS tracking shows cougars at hundreds of locations near Front Range neighborhoods.

For example, during one week last month, AF69 was located at three spots near Broadway in Boulder between dusk and 2 a.m.

Tracking data also detail AF69’s move that week from foothills north of Boulder Canyon to a neighborhood where she killed a young buck, which she cached under a conifer tree near a house, covering it with landscaping mulch and pine needles.

“The interesting thing is that she’s living in these neighborhoods but she is rarely seen,” Alldredge said. “By and large, this cat is making a living in the urban-exurban environment. She’s killing deer. She’s doing the best she can in this area where she was born and raised. Part of the city is her home range.”

The growing body of research on how AF69 and other cougars survive as Colorado’s human population expands includes a case where a cougar cached a deer carcass in a suburban carport under a Chevy Blazer.

State researchers are driven partly by a need to test the effectiveness of the hazing techniques wildlife officers have been relying on to deal with mountain lions that get too close to people for comfort. They douse offending cats with pepper spray, shoot them with rubber buckshot or set off explosives.

The hazing is intended to drive the cougars back to undeveloped land. The question is whether hazed mountain lions will stay away. State supervisors say hazing, if it works, could help reduce the number of mountain lions euthanized each year.

At least 48 cougars have been put down over the past decade, according to data provided by a Parks and Wildlife spokesman. The data show 37 were killed between 2006 and 2010, more than triple the 11 killed during the previous five-year period.

In the Boulder area, two of six cougars tracked in recent research appeared to be spending at least 15 percent of their time in edge neighborhoods. Those two were killed. Another two that entered the city only rarely were darted and moved more than 100 miles away. AF69 and another cougar have been left alone.

Hunting mountain lions is legal in Colorado, and about 350 are killed each year.

The total population of 3,500 cougars is considered stable, but the estimate is soft because the big cats are hard to count. In a separate state study, researchers are looking into the impact of hunting.

Two incidents last week raised familiar concerns about public safety. A cougar attacked pastured llamas west of Loveland. Another snatched a small dog near a porch outside Carbondale.

“We continue to get incidents where people are confronted by animals. But typically, there is no threat involved. It is just a person running into a mountain lion,” said Steve Yamashita, northeast regional manager for Colorado’s Division of Parks and Wildlife.

Nobody is expecting the human-cougar interactions to abate as more people move to Colorado. For that reason, state wildlife managers want to expand long-running efforts to teach people about mountain-lion behavior, Yamashita said. “We’re trying to tell people how they can live with these predators,” he said.

At his house west of Boulder, Morris said he was impressed with how state biologists handled AF69 — prioritizing human safety but indicating that cougars have rights. It’s an approach he supports.

Living with mountain lions “makes you wary. However, it doesn’t stop us from doing anything,” said Morris, who keeps his pet cat indoors, saying it would not survive long in the surrounding woods.

“I know there are some people who are concerned about going out after dark on the streets. But I think that’s more from bears rather than mountain lions,” he said. “We’re aware that these lions do not want to be near humans.”

Bruce Finley: 303-954-1700 or bfinley@denverpost.com