After about 50 minutes of searching and sniffing on and off a trail in Pupukea on the North Shore of Oahu, Qana, a 4-year-old Belgian Malinois, has found her first invasive plant of the day.

Qana is one of several dogs that belong to a number of owners who volunteer their time to Conservation Dogs of Hawaii, a nonprofit based in Honolulu, founded by Kyoko Johnson.

Qana has been trained by Johnson and her owner and handler, Roberta Bitzer, to sniff out Chromolaena odorata, otherwise known as devil weed, for its pitchfork leaf pattern. This harmful plant is ranked number 23 on the 100 of World’s Worst Invasive Species list, and has a high score on the Hawaii Pacific Weed Risk Assessment, which ranks plants based on habitat, distribution and history.

Conservation dogs of Hawaii
Qana alerting her owner and handler, Roberta Bitzer, that she has found a devil weed shrub. Alicia Lou/Civil Beat/2022

Originally from Tokyo, Johnson is a professional dog trainer who specializes in ecological scent detection. She moved to Hawaii almost two decades ago and first established CDH in 2016. Johnson initially wanted to train dogs to detect cancer but later changed her focus, and began a pilot project in 2019 teaching them to detect devil weed.

Along with their owners, Johnson has worked with nine other dogs — the oldest of which is 6 years old — in devil weed detection, who are all in different stages of training. Qana is one of the three most experienced, while Zephyr, Johnson’s 8-month-old black Labrador retriever, the youngest, knows the odor but has not racked up a lot of experience in the field.

Though the noxious pest can be toxic to dogs if consumed in large quantities, Johnson said the CDH canines don’t try to eat it. They’re too excited to get their reward for locating the invasive plant. It also helps that the devil weed leaves have a distinct turpentine smell when crushed, that even humans, who have 295 million fewer scent receptors than dogs do, can smell.

One of the six devil weed plants 4-year-old Qana finds during a search in Pupukea. Alicia Lou/Civil Beat/2022

Devil weed can quickly take over its surroundings and grow 4 to 15 feet tall. Native to North, Central and South America, devil weed was first detected by the Oahu Army Natural Resources Program in 2011 on the Kahuku Motocross Track on Oahu. The program then alerted Oahu’s Invasive Species Committee. It has since been found in Kahana Valley, Pupukea and Aiea.

Erin Bishop, the outreach coordinator for the Oahu Invasive Species Committee, said that because the Kahuku Motocross Track doubles as a training area for the military, the most logical theory is that the devil weed’s pesky seeds hitchhiked on military equipment, most likely from Guam due to the heavy military traffic. Bishop added, though, that the discovery on the track wasn’t necessarily the initial introduction, as no one can say for certain how the plant made its way to Hawaii.

Since World War II, Guam has been overrun by a series of invasive species such as devil weed and the coconut rhinoceros beetle, which was first detected in Hawaii in 2013 at Joint Base Pearl Harbor-Hickam during a routine survey by the Hawaii Department of Agriculture.

A pathway analysis conducted by the U.S. Forest Service in 2015 identified imported live plants as the highest risk for introduction of pests and diseases to Hawaii. The invasive species committees are collectively working hard to block other species from entering the state, such as the brown tree snake, which has devastated Guam.

Bishop said the Oahu Invasive Species Committee teamed up with Johnson at CDH in late 2018, hoping the dogs could help eradicate devil weed.

Oahu invasive species committee
Where the invasive plant devil weed has been found on Oahu. Courtesy: Oahu Invasive Species Committee

The weed was also detected at a motocross track on the Big Island in early 2020, according to Franny Brewer, the acting program manager for the Big Island Invasive Species Committee. The committee, after hearing about CDH’s success on Oahu with devil weed, commissioned the organization in May with an innovation grant from the Hawaii County Department of Research and Development.

Brewer said in addition to crowding out native species, devil weed has two particularly negative aspects: It contains a chemical that makes the plant extremely flammable even absent dry conditions, and it’s toxic to livestock, such as cattle and horses.

Qana, working with Bitzer and Johnson, was sent to several locations on the Big Island where the committee believed devil weed might be growing. Bitzer said it was the best three weeks of Qana’s life.

The process of training dogs like Qana, Johnson explained, involves classical conditioning. “It’s sort of like Pavlov’s dog where they salivate when they hear the bell that’s associated with food,” Johnson said. “So instead, we pair the target odor, which in this case is devil weed, with their food or toy reward, whichever one the dog wants to work for, and they start to seek out that target odor as if it were their food or toy.”

Though some dogs prefer to be rewarded with a high-value treat such as chicken or steak, Qana’s most coveted pay-off is a plastic frisbee.

Johnson said even though many dogs have a good sense of smell, they lack some of the primary traits for this type of work, including physical endurance, confidence, work ethic and good social skills.

conservation dogs
Owner and handler, Roberta Bitzer, and her dog, Qana. Bitzer, who has a full time job as a canine lead, is also a mother of two. She tries to take Qana out on field searches at least twice a month to keep her happy. Alicia Lou/Civil Beat/2022

Qana embodies all of these qualities. After two hours of sniffing and being dragged in different directions when the wind changed course, according to the GPS tracker built into her collar — Qana had logged five miles and somehow was still full of energy.

For the most part, Qana’s nose led her off-trail, leaving Bitzer no choice but to scoot down steep, pathless hills. But the dirt stains and pine needles on Bitzer’s clothes were a small price to pay, because Qana found five more devil weed plants.

“It is 100% teamwork,” Bitzer said.

Bitzer grew up on the outskirts of Rio de Janeiro, and has rescued more stray animals than she can count, but said she has never before felt the connection she now has with Qana. “It’s unbreakable … doing this kind of training, you truly get to understand your dog and your dog understands you,” she said.

In lieu of barking, which could be considered disruptive, Qana alerts Bitzer by either circling the area, attempting to point with her nose, or looking back and forth between Bitzer and the area where she’s detected a plant, a method that Bitzer said Qana has naturally developed.

Qana is also trained to sit near the plant, and though it’s evident that she tries, she is simply too excited, knowing she’ll be rewarded if she is right. And more often than not, she is.

Each time Qana correctly locates a devil weed plant, Bitzer rewards her with her frisbee. Then, while Qana is busy playing, Bitzer removes the plant by carefully digging it up by the roots, and documents its location and whether it has matured. If it has, its flowers drops seeds that can further exacerbate its spread, and Bitzer or a member of the Oahu Invasive Species Committee will come back to search for new plants.

Outside of working with Qana, Bitzer is also the canine lead for the Coconut Rhinoceros Beetle Response team, and works with dogs trained by the U.S. Department of Agriculture to find the beetle’s breeding sites.

Dogs have also been trained to sniff out the smell of rapid ohia death, Covid-19 and many other scents. Most recently, Johnson, working with Rudi, a one-year-old yellow Labrador, just returned from Maui after they helped search for coqui frogs, though they are still in the early stages of testing.

Johnson, who’s always loved dogs and thought of them as “furry kids,” said she didn’t realize how underutilized their abilities and instincts are. Training dogs to detect scents has given her a huge appreciation. She’s proud of what they’ve accomplished in the last three years, and hopes to continue to build local capacity with dog and handler teams.

“No matter how much I accomplish, I always feel like there’s so much more to do! I think conservation is just that way — the work never ends,” Johnson said.

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