Even in winter, there is still the occasional deer poacher, Harner said.
On this morning, Harner stays close to the Potomac River, surveying the tow path. At one point he locates a vehicle parked off the path. He gets out of his truck and inspects it for signs of hunting - a gun case or other gear.
Nothing doing here. If he had found evidence the car's owner was hunting, the next step would have been to search the nearby area.
This morning is quiet. Weekdays are normally calm, because most people are working, Harner said. Weekends and nights provide much more activity, he explains.
Even during busy times, though, Harner said there is only so much that officers discover on random patrol. A good bit of their work comes from tips that people call in.
"I don't think I can emphasize enough how much we depend on citizens for information and complaints," he said. "They're our eyes and ears."
At about 10 a.m., Harner hears a report of a bank robbery on Virginia Avenue. Picking up his two-way radio, he swings into action. Guessing the robber might be heading for nearby Interstate 81, Harner makes a sweep south to the West Virginia border, looking for anything out of the ordinary.
It is the kind of action Harner said he takes from time to time. Natural Resources Police have full arrest powers and carry weapons. Mainly, Harner said, they assist investigations along the river and on state property.
Harner said he has helped conduct investigations of rapes, assaults, car break-ins, missing people and a host of other crimes. He said Natural Resources officers' knowledge of the Potomac River is a great asset in many criminal investigations.
On this day, Harner uses the lull to check out a few taxidermists in the county. Harner and two other officers must check 152 permits for game husbandry, taxidermy and fur dealers by April.
In a little more than a month, depending on the weather, Harner will start gearing up for fishing season. As with hunting season, it will present a new round of cat-and-mouse between authorities and those who would bend the law.
Harner said some are so bold that they follow trucks as officials stock the waterways with trout and other fish.
"Greed - nothing but greed," he said.
There is no Most Wanted list, but Harner said there are about a dozen or so perennial law-breakers. Catching them can be as difficult as nabbing a murder suspect. Natural Resources officers employ many of the same techniques used in other criminal cases.
Harner said those pursuits are the most challenging aspect of his job.
"Trying to locate these known outlaws, notorious outlaws and catch them," he said. "The good ones have done it a long time and gotten away with it."
Harner said he greatly enjoys the variety and changes of pace that come with the job.
"When hunting season winds down, I'm about ready for it to end and about the same can be said for boating season," he said.
A lifelong hunter, Harner said he was attracted to the job by the same culture that prompts good outdoorsmen to police themselves.
And for those who do not, Harner said he'll be ready.