Upon completing his Black Friday shopping at Savers in Kahului, Upcountry resident Lenie Lawrence heard a loud chirping coming from somewhere in the parking lot.

Other shoppers heard it too – one woman insisted someone’s car alarm had been triggered.

But Lawrence recognized the call of a coqui frog, an invasive species that could decimate native ecosystems if it gains a foothold on Maui. Lawrence, a retired police officer, investigated further and followed the chirping sound to a cluster of hedges near the neighboring gas station. He quickly spotted the brown, dime-sized frog, knocked it out of the bushes and squashed it with his shoe. He subsequently reported the sighting to the Maui Invasive Species Committee.

“I don’t usually like to get involved with this kine stuff, but if you don’t do something, one can turn into one thousand,” he said by phone Monday.

Native to Puerto Rico, the frog was accidentally introduced to Hawaii hidden in plants around 1988. Populations have exploded in the last 15 years from presumably a single infestation to over 200 on the Big Island alone. A female coqui can lay a cluster of 34 to 75 eggs once every two and a half weeks, and the frogs have no known predators in the islands. Coquis have voracious appetites that can threaten Hawaii’s unique insects and spiders, and the endemic birds and other native fauna that rely on the insects for food.

The frog has already established itself on over 60,000 acres on the Big Island, keeping residents and visitors awake with high-pitched mating calls, often from dusk till dawn. An infestation could contain as many as 20,000 frogs per acre, experts said. Hopes of eradicating the species from the Big Island are lost, but experts are working diligently to ensure the frog does not spread to other islands.

“I can see if one get into your property, you never going to get any sleep,” Lawrence said. “They make the chickens look like nothing.”

Coquis have been found on Maui, Oahu and Kauai as populations on the Big Island grew. The Maui Invasive Species Committee has been systematically tracking and controlling the coqui presence on Maui since 2005. A total of 19 population centers, where there are five or more calling frogs, have been found on Maui. MISC has eradicated 12 of those.

Encountering a single coqui frog in areas like Kahului or anywhere around the island, is not uncommon, MISC Manager Teya Penniman said.

“It’s been true for a number of years. The reason we continue to get new introductions to Maui is from the Big Island, so we have for years been chasing down single frogs in different places,” she said.

Many of the frogs found in Central Maui, like the one in the Savers parking lot, could have hitchhiked in plants or cars that sneak past agricultural inspectors at harbors and ports, she said. The tiny frogs and eggs are also introduced via plants shipped to nurseries.

Penniman said that some nurseries that import plants from the Big Island make the effort to be certified by MISC as “coqui-free,” but not all nurseries do. Customers should ask nurseries if they are certified to prevent the spread of coquis on Maui.

Meanwhile, a full-time crew is working with landowners to contain a known coqui infestation in Maliko Gulch that stretches about 4 miles from Kaluanui Road to Maliko Bay.

“Maliko is our huge, huge challenge at the moment,” Penniman said, adding that the effort to contain the infestation will take “years.”

Much of the challenge is habitat modification, she said. For example, the team must first cut down overgrown cane grass in parts of the remote area before it can effectively spray pesticide.

Neighboring landowners have aided in the effort, wanting to limit the population before it gets out of control.

“It’s a problem that’s been in the making for a long time. We’ve had a perfect storm of excellent weather the last few years and (frog) population reaching critical threshold and reductions in state and federal funding,” Penniman said.

If you spot a coqui frog, contact MISC at 573-6472 or miscpr@hawaii.edu.

* Eileen Chao can be reached at echao@mauinews.com.