TURNER – Head down, ears pricked forward, Willie Nelson the dog watches the speeding pickup with unmatched intensity.

He’s a dog with a mission.

The truck is 100 yards away. Fifty yards. Twenty.

Suddenly, the border collie can’t contain himself.

Hopping, spinning, he dances at the side of the road. The truck blows past, ruffling Willie’s fur, and he barks once.

Tongue lolling, he trots a few feet down the road until the truck disappears in the distance, then returns to his post at the edge of Nezinscot Farm.

When there are no sheep to herd, Willie makes do with commuters.

“With border collies, they have to stay busy all the time,” said owner Gloria Varney. “This is his pastime.”

Varney got Willie as a puppy three years ago. For a while he stuck with herding the farm’s sheep. About a year ago, he moved onto the cars that travel Route 117.

Varney doesn’t know why.

“I have to control how much he does it. He always wants to herd,” she said.

Willie seems to play favorites. On one recent morning, he barely cast a sleepy glance at a white van. But he spun a couple of times at a passing police car and an orange delivery van.

A teal four-door sent him into a frenzy.

Exhausted, Willie collapses at the edge of the road in between passers-by. He constantly watches, though, sweeping his gaze from left to right. He doesn’t set a paw onto the roadway.

Willie ignores the farm’s roaming cats and chickens. He doesn’t give a second look to people walking by. But he jerks to attention at the throaty chug of a truck a half mile away.

Willie’s roadside antics have gotten the attention of neighbors.

“Now when people give directions they say Look for the whirling dog. Willie the whirling dog,'” Varney said.

After school and during rush hour, Varney brings Willie inside. The summer kitchen is his rest spot. It’s the only place he can’t get out.

When she got Willie, Varney thought her older, sedate Akita-mix, Jack Daniels, would be a calming influence. So far, it hasn’t happened.

While Jack Daniels sleeps, Willie Nelson herds.

“It’s just the behavior of a border collie,” Varney said.