by Mona Patterson and Kristen Goodhue

Dogs, with their ability to sniff out unseen objects, have become key players for many teams, from search and rescue missions to hunting. But lately, they’ve received a new welcome—onto the team of plant conservation. This summer, orchid scientist Melissa McCormick embarked on a search for the endangered orchid Isotria medeoloides, commonly known as the “small whorled pogonia.” Accompanied by two Labradors and their handlers, McCormick set out to survey Fort Walker, Virginia, for any sign of the elusive orchid.

The small whorled pogonia hasn’t been seen in Maryland or D.C. for at least two decades. Federally listed as “threatened,” the orchid is endangered or imperiled in almost every state where it still occurs. Recently, however, scientists discovered a significant population in Virginia, where it’s also listed as endangered.

Surveying the small whorled pogonia can be tricky. Their small size and green color make them blend into their surroundings. To make matters worse, it has a doppelganger: Medeola virginiana, the Indian cucumber root. Both plants share a similar leaf pattern and color when not flowering, making them difficult to distinguish with the naked eye.

“It’s not super obvious,” said McCormick, a biologist with the Smithsonian Environmental Research Center (SERC) and director of the North American Orchid Conservation Center. “But to a dog’s nose, apparently it is.”

Training Paw Patrol

Two Labradors joined McCormick on the search: Encore, a 9-and-a-half-year-old black lab, and Grand, a 7-year-old chocolate lab. The North American Orchid Conservation Center, a coalition that McCormick leads, spearheaded the effort, with support from the U.S. Botanic Garden.

“Encore is a little bit more of a timid dog,” said Carl Dunnock, Encore’s handler. “Very high energy, but as we are surveying, he tends to stay a little bit closer to me.” Grand, on the other hand, tended to wander a bit farther from his handler, Carl Messick.

Both dogs learned to sniff out orchids at the Maryland Detector Dog Program, run by the U.S. Department of Agriculture (USDA). The USDA looks specifically for high-energy adult dogs, and nearly always recruits them from shelters. They’re generally not too picky about breeds in the recruitment stage, according to Trevor Michaels, a USDA wildlife biologist who works with the dogs. The dog’s personality and abilities—and enthusiasm for toys as a reward—matter more. Breed comes into play when deciding which environments are best for the dogs.

“We wouldn’t want a Chihuahua working in the marsh with us in Alaska,” Michaels said. “It’s probably not going to work well.”

Grand and Encore already had experience with animals, sniffing out red-tailed boas, feral swine and the droppings of invasive nutria rodents. But the small whorled pogonia was their first plant.

To train them on the orchid, Dunnock and Messick began indoors. First, they exposed the Labradors to the scent of small whorled pogonia leaves in small vials. Gradually they moved outdoors, where the dogs searched for dried pogonia leaves in tea bags. Finally, they took the dogs to Fort Walker and Prince William Forest Park to see if they could find live, already-known populations of small whorled pogonias in the wild. Upon sniffing out the orchids’ scents, Grand and Encore would sit by the suspected orchid, waiting for their handlers’ approval—and their requisite toy prize.

Sniffing Out the Sleeping Flowers

Once field training was over, McCormick, Dunnock and Messick moved on to the real test: finding orchids the scientists didn’t yet know about. In their most recent expedition, Grand and Encore found several new Isotria orchids just outside populations scientists had already been surveying.

“We’ve also had them cue in on some areas that, as far as we know, there are no plants there,” McCormick said. “And often both dogs will cue in on the same spot.”

McCormick suspects—though cannot yet confirm—that the dogs were finding dormant orchids underground. Some orchid species can enter a dormant phase that can last for years, likely living off stored nutrients and relying on their relationships with soil fungi.

Because orchids are so fragile, scientists can’t dig them up without endangering the orchids’ lives. Instead, McCormick’s team marked the areas the dogs identified with flags. Next year, they will return to the marked locations to see if any small whorled pogonias have reemerged.

Once Encore and Grand “retire,” they’ll almost certainly spend their remaining days in a dog-loving home. Handlers always get first dibs on adopting their canine partners. And if for some reason a handler can’t adopt, there are plenty of eager households waiting on the sidelines. Even dogs that fail their training and wash out of the program typically find homes, according to Michaels.

“There’s always a long waiting list for these dogs,” he said.