The time of year was a contributing factor. "From January through March, they're pairing up and defensive," says Division of Wildlife officer Claire Secrist. And hungry, too: During the winter, food sources like berries aren't available. When subdivisions are built on traditional coyote habitat, confrontations between humans and coyotes tend to be intensified. Gardens, shade trees and water attract squirrels and other small animals, which in turn attract coyotes, whose weight can range between 25-35 pounds.

Shortly after the Broomfield attacks, marksmen hired by the Division of Wildlife killed five coyotes in the area. They also pursued the coyotes in Denver but never found them. As for Erie, "I believe we removed one coyote in that area after that incident," says Churchill.

Other encounters didn't involve attacks, but were nonetheless alarming. A family of coyotes denned underneath the porch of an elderly Lakewood woman in June 2008, dining on local dogs and cats; their reluctant hostess was afraid to leave her house. The DOW hosted a daylong symposium early in 2009 to encourage municipal officials to formulate their own plans to deal with the problem. How do you smooth out relations between arguably the two most successful omnivores on the continent?

Aurora, a city of 330,000 people on Denver's eastern border, emphasizes education:

"We do a full-court press," says Mary Ann Bonnell, Aurora's senior natural resources specialist. At homeowners' meetings and in brochures, residents are urged not to feed coyotes, and to keep their dogs on leash. As Churchill points out: "Fifty percent of the incidents where a human gets injured involve an off-leash dog."

"The people who love coyotes inappropriately are as bad as those that hate them," says Bonnell. "They're the ones who are 'cootchy-coo'-ing them onto the back porch, feeding them peanut butter and jelly sandwiches."

Bonnell also urges Aurora residents to scare coyotes away -- by clapping their hands, stomping their feet, shouting or (her favorite) noisily shaking an Altoids tin filled with pennies. "If you see one in the wilderness, that's fine. But if it's walking down a suburban street, casing the joint, it's not something you should be a passive observer of. If you don't scare them off, I think that does create a different kind of coyote."

Bonnell listens to the owners of $600,000 homes yell that golf courses are no place for wildlife, and receives phone messages like this one, from a resident of a low-income housing development: "There's a lotta coyotes over here. ...They're all over the place, chasing rabbits and shit. ... If you walked up on them they'd probably tear your ass up."

The city of Denver, which has more than 600,000 human inhabitants, has not experienced the sharp recent increase in coyote incidents reported by the suburbs, perhaps because the city proper has less open space. Still, Denver is formulating a coyote plan with the same educational emphasis as Aurora, Broomfield and Centennial, three communities whose coyote control program is run with the help of the environmental group WildEarth Guardians. Like those suburbs, Denver doesn't rule out calling in the state Division of Wildlife to kill coyotes seen as dangerous. In January, after a coyote trotted toward a 4-year-old child in City Park, DOW officers killed it. They also killed a coyote that bit a 12-year-old boy in the western suburb of Golden in April.

To better understand how to reduce conflicts, a group of Front Range communities has funded research to analyze 3,600 local human-coyote encounters over the laFst five years. Over 80 percent of these were simply coyote sightings. This particular study, which will conclude in about a year, will add to the knowledge generated by studies of coyotes in a range of cities, extending as far east as Newport, R.I. -- where coyotes are thick in the mansion district.