"I thought we'd find just a few, and that they'd all be problem animals, but a whole new world opened up," says Stan Gehrt, an Ohio State University biologist and the lead researcher in a 10-year-old ongoing study in Chicago. The native coyotes withdrew from the rapidly growing metropolis in the late 19th and early 20th centuries. But within decades they were back -- and not just in Chicago. Once concentrated in the High Plains and the Southwest, coyotes have spent the last century moving east even as wolves and cougar populations were being decimated. Coyotes are now found in all 49 mainland states. It's an expansion that has been called "unparalleled by any other species of terrestrial mammal in recent history."

"We've had easily hundreds -- but more likely thousands -- of coyotes in the Chicago metro area, along with 9 million people," said Gehrt. Coyotes comprehend traffic patterns, for example. "They look in the right direction before they cross the road. I had totally underestimated them. I still underestimate them."

The number of nuisance coyotes trapped in the Chicago area increased sharply between 1990 and 2002, but Gehrt says in the last decade there has been "at the most, possibly one bite" to a human.

Southern California, where coyotes are also native, is another story. Perhaps because Los Angeles is surrounded by -- and interspersed with -- so much wild country, coyotes thrived even as the city ballooned. In 1937-'38, Los Angeles County offered a $1 bounty on coyotes. By 1961, they were seen along the edges of movie stars' estates, living "lives of ease and luxury beyond the wildest dreams of their hardscrabble ancestors," according to Robert Froman, author of The Nerve of Some Animals.

Some 136 Californians reported being injured by coyotes between 1961 and 2007, according to Robert Timm and Rex Baker in their 2007 paper, A History of Urban Coyote Problems. The most tragic of these was the case of toddler Kelly Keen, who was bitten in her driveway in Glendale in 1981 and dragged across the street before her parents rescued her and rushed her to the hospital, to no avail. Her death spurred L.A. county officials to trap and shoot 55 coyotes within a half-mile radius of the attack site in 80 days.

Glendale still kills problem coyotes, but the local government also provides education on its website, advising people not to put out their trash the night before pickup, for example, but to wait until the morning.

The only other recorded North American fatality involving coyotes occurred last October, when a 19-year-old woman was killed in Nova Scotia's Cape Breton National Highlands Park. Some theorize that the animals involved were wolf-coyote hybrids.

Despite tragedies like these, statistics don't show coyotes as a significant public safety threat. The only recorded coyote bite in the history of Aurora occurred in 2009, the same year that Aurorans were bitten by domestic dogs 207 times. To add further perspective, Bonnell points out that across the nation, an average of 2.18 people are killed by vending machines every year.

And after the upswing in coyote bites in the Denver area during 2008-'09, things have calmed down again, with only one reported bite so far this year (the 12-year-old Golden boy). "I'd hope the decline is because of our awareness," says Churchill, noting that the year isn't over yet. She adds that a report of a rabid coyote in the Southwestern Colorado town of Cortez in November "at this point is not a cause for undue concern" to Front Rangers.

Unlike wolves, coyotes evolved to eat animals smaller than themselves -- a fact that endears them to some suburbanites. Bonnell recently got two phone calls "lamenting the fact that the coyotes are gone, because now there are raccoons and skunks. People don't realize the ecosystem services that coyotes provide. They do a terrific job of managing economically damaging species. They're the middle-management predators."

That's fine if you're trying to rid your yard of skunks, but not so good if your Bichon Frise gets mauled. Which brings us back to Greenwood Village, where animal control specialist Jay Stewart has snared, trapped or shot close to 200 coyotes since 1993 -- mostly on behalf of private residents. In 2007, under contract for the city of Greenwood Village, Stewart placed rubber-padded leg-hold traps in the Marjorie Perry Nature Preserve. Although he'd posted warning signs, he caught two off-leash dogs, raising the ire of local residents.

He was hired again early in 2009, after the incident with the 14-year-old boy. Stewart shot the coyote he believed was responsible. Following other coyote complaints, he showed up at the crack of dawn in local parks and other open areas to dispatch the culprits, only to have his efforts sabotaged by hazers, who scared the coyotes away.

Stewart professes respect for coyotes -- "They're going to be here long after we're gone" -- and says he followed the instructions of the Greenwood Village City Council and focused only on problem animals.

"I was trying to do the right thing, and the animal-rights people just tried to make it as ugly as possible," he says. His traps were cut, and he says he received 29 death threats, including one that described his home and his two mules in intimidating detail.

Tempers ran so high in Greenwood Village that Stewart was asked to step down a couple of months after he began. The municipal police took over coyote control, shooting eight between mid-November 2009 and Jan. 27, 2010. (No coyotes have been killed since then.) Lt. Joe Harvey says "things have quieted down a lot," adding that the police have done more and more hazing. Still, for coyotes that appear aggressive, lethal control remains an option.

"When it comes down to it, we're going to err on the side of reducing the fear of the citizens," says Harvey. Some residents speculate that the city is also trying to avoid the litigious impulses likely to surface if a Villager were to get hurt by a coyote. "People look for the deep pockets," says one, "and Greenwood Village has the deep pockets."

Says Jay Tutchton, a lawyer for WildEarth Guardians, resident of adjoining Centennial, and a member of a vocal group of critics of the city's coyote policy, "Greenwood Village's fear of coyotes is so delusional. ... I think the city would like to preserve the pretty scenery without any of the inconvenient residents."