Keeps you warm, too, Mr. Schmidt said, patting his chest on a recent cold morning at Golden Gate Canyon State Park, about an hour west of Denver, as the snowcapped peaks of the Continental Divide shimmered in the distance.
Two recent shootings of wildlife officers one killed in Pennsylvania while confronting an illegal hunter, the other seriously wounded after a traffic stop in southern Utah have highlighted what rangers and wildlife managers say is an increasingly unavoidable fact. As more and more people live in proximity to forests, parks and other wild-land playgrounds, the human animal, not the wild variety, is the one to watch out for.
We're seeing a little bit more of the urban spill into the wild spaces city violence in the country, said John Evans, an assistant branch chief of law enforcement operations at the National Park Service.
At this time of year, when hikers give way to hunters, there is a corollary to Mr. Evans's point that would make even the most hardened urban police officer blanch: weapons are everywhere in these woods.
I know that everybody I confront has a gun, said Mr. Schmidt, 36, who has five years on the job with the Colorado Division of Wildlife.
Guns also became legal in many National Parks this year under a law enacted by Congress in 2009. And many parks and recreation areas around the nation have also suffered staff cuts in recent years, reducing the presence of badge-wearing authority figures on patrol. But rangers and wildlife workers say the key variable defining the job has not changed: because of the vast distances to be covered, especially in the West, every ranger is a solo act.
In the lonely, beautiful places where they work, knowing when to walk away, or run, rangers say is Lesson 1. Fifteen wildlife or park employees have been killed on duty, most of them by gunshot, since 1980, according to the North American Wildlife Enforcement Officers Association.
A huge portion of it is gut instinct, said Jacob Dewhirst, 26, a state park ranger who works in western Colorado, where checks on hunters' or fishermen's licenses often take place in the lonely back country.
Many wildlife agencies have responded to the heightened dangers with new equipment and training. Since 2007, National Park rangers in many parks have been equipped with Tasers that can immobilize a would-be attacker.
Mr. Schmidt has an AR-15 semiautomatic assault-style rifle in his truck, and a computer on the dash that can in ways old-time rangers never knew check a vehicle license plate before a ranger's first approach.
But rangers and wardens also inhabit a mixture of roles that they say can sometimes make them more vulnerable. They are ambassadors and stewards of a public resource, and most have backgrounds in some aspect of the natural sciences. But they also have full police authority, up to and including using lethal force if necessary.
Mr. Evans described it as a duality: A nice guy, prepared for an idiot who is ready to do me harm.
For Mr. Schmidt, who has a degree in wildlife biology, that balancing act welcoming and wary comes down to always having a clear line of retreat. Whenever he stops to check a vehicle or speak to a hunter, his truck door is always left open, the engine running.
What has made the recent shootings even more chilling to many rangers is that events unfolded from encounters of the sort officers do all the time. In the Utah case, the gunman, who has still not been caught, apparently opened fire when a Utah State Parks ranger, Brody Young, 34, approached after a traffic stop. In the Pennsylvania case, David Grove, 31, was killed after he confronted a man hunting illegally with a spotlight, which makes deer and other animals disoriented and easier to shoot.
It's very easy to comprehend exactly what David was dealing with at the time of the shooting, said Richard A. Johnston, a regional law enforcement zone officer with the Fish and Wildlife Service, who traveled from his home in Kansas to attend Mr. Grove's funeral.
For some officers, like Ty Petersburg, who manages a heavily used district west of Denver for the Division of Wildlife, the line between urban crime and wildlife crime gets blurred all the time.
A couple of years ago, Mr. Petersburg began following a suspicious-looking vehicle on Interstate 70 a pursuit that led all the way into the suburbs of Denver, where the driver leaped from his car to attack. Minutes later, perhaps 30 local and county police officers arrived in a siren-screaming swirl of backup that Mr. Petersburg, 31, had summoned by radio. It was a familiar scene: the police helping out their own.
More often, he said, it is the opposite case, where help is willing in spirit, but impossible in practice. Earlier this fall, for example, Mr. Petersburg was in a mountain region in the middle of nowhere and came upon a vehicle driven by a man with outstanding arrest warrants on his name and lots of cocaine in his car. He again called for backup.
We'd like to come help you,' he quoted the nearest big urban county sheriff's office as saying, But we don't have a clue where you're at.' | 
