NAME THIS BREED of canine.

It possesses lightning speed and Olympian endurance. It’s so keenly intelligent that it’s been known to comprehend the names of as many as 1,000 objects. Its agility is such that it dominates dog dancing and disc competitions. So powerful is its herding instinct that one reportedly fixed its stare on a remote-control toy car for the 120 seconds it was moving.

Not that North Guilford’s Ellen Black, who’s currently preparing her purebred border collies for the sheep dog competition at the Big E in Springfield, Mass. this Monday, expects any of the four to exhibit those kinds of skills, much less move a flock of 500 sheep or cover a hundred miles a day in all seasons and in every kind of weather.

“That’s what they were bred to do so they probably could,” said the perennially upbeat 56-year-old as she stood in the hay-scented air, shepherd’s crook in hand and whistle around her neck, watching her prized three-year-old border collie Peig (Peg) lock her gaze on a sheep with the wolf-like predatory stare hard-wired into every border collie to manipulate stock as massive and menacing as a 2,000-pound Angus Black steer.

Of course, there’s a difference between knowing what her dogs have the potential to do and training them to realize their full potential. Which is precisely what drew Black to sheep dog trials, the series of increasingly popular weekend-long competitions over the spring and summer that have been termed the X-games of the dog world.

It all started in 1997, when she got her first border collie to manage her sheep and goats. “That led to me learning to be a handler, a trainer, and so on,” said the North Guilford native as Peig, her body a blur of paws and tail, drove a reluctant sheep back to the herd on the emerald-green fields of Dragonfly Farm, which has been in her family since 1835.

While making a name for herself and her charges in sheep dog trials, Black also is an investigator for non-profit organizations protecting adults with disabilities. On top of that she writes grants. Not to mention Up, Up & Away, a thriving business she runs with her husband Bill, a retired accountant, that provides relief for property owners bedeviled by Canada geese.

In her spare time, she knits sweaters, mittens, gloves, and hats from the wool of the sheep her dogs herd. Some will warm her and Bill through the winter. Some she’ll sell down the road at the Dudley Farm farmer’s market on Saturday mornings.

So, really, what happened was this. In 1997, Ellen Black met her multi-purpose match. Not only that: she found a group of tireless and enthusiastic companions who were happiest when they had a job to do. Specifically, helping corral any sheep that wandered away from the herd on their way to and from the fields each day.

That’s where sheepdog trials come in. Plainly put, they serve as a barometer of the skills dogs use every day on the farm. They’re also the most difficult test of human-dog communication ever devised.

It seems quite simple, the handler using a dog to herd sheep through a series of gates and into a pen, using only voice and whistle commands to communicate. Except the border collies must outguess unfamiliar and headstrong sheep and disrupt their flock mentality by splitting the herd under the pressure of a time clock and with points lost for any error. And the handler is often so far away that she can see neither dog nor sheep.

That her dog almost invariably gets the sheep and brings them back is, for the modern-day shepherdess, the appeal of working with border collies, both on the farm and in competitions. Not for their vocabulary or their dancing skills or Frisbee-tossing prowess.

“A dog who’s your working partner, who’s got your back when it’s out there reading the physical reaction of sheep for you, who lives and breathes to help you every day,” she said, her face breaking into a smile. “Now that’s truly magical.”

Dragonfly Farm is located in North Guilford. For sheepherding demonstrations and Canada Geese nuisance issues, visit www.canadagoosecontrol.org., email dragonflyfarm@att.net, or call 203-457-1459.