Colorado wildlife officials are celebrating some long-awaited good news – the mountain toads are making tadpoles.
For seven years, biologists have been toting tadpoles to high-elevation bogs and ponds in a massive effort to save the inch-long boreal toad. And for the first time at a mountain wetland above Pitkin, they’ve discovered that those transplanted toads are making their own babies in the wild.
“It’s a really big deal,” native aquatic species biologist Daniel Cammack said in a Colorado Parks and Wildlife news release.
Boreal toads, which live in wetlands around 11,500 feet and spend their winters buried under multiple feet of snow, have been dying off at a rapid pace across the Rocky Mountain states. A fungus that infects the toad’s skin with a cluster of spores, then bursts and spreads through the water to other toads, is to blame.
Colorado biologists have been trying to stop the fungus by dipping the tiny toads in a wash nicknamed “purple rain” and have been taking new tadpoles from a hatching center in Alamosa and dropping them in wild ponds.
This summer, when Cammack went to check on his transplanted toads above Pitkin, northeast of Gunnison, he found they were reproducing, a discovery that Colorado Parks and Wildlife called “potentially game-changing.”
Cammack’s team has been bringing tadpoles to the wetland since 2018, which is about the length of time it takes for a female toad to reach reproductive age.
The state wildlife agency has stocked about 20,000 tadpoles at the Pitkin bog, most of which began as eggs that were collected from the backcountry and raised to tadpoles at the Native Aquatic Species Restoration Facility in Alamosa. In 2022, biologists threw in 570 tadpoles from the Denver Zoo Conservation Alliance.
Before the relocation efforts, there were no boreal toads at the Pitkin bog.
“Everyone who has been involved in this project has poured their heart and soul into it,” Cammack said, calling it a “really special day.”
Now, biologists will watch to see if the tadpoles turn into toadlets and then into adult toads. It will become only the second place in Colorado where transplanted toads have had tadpoles that grew into toads. The first is near Cameron Pass, outside of Fort Collins.
Boreal toads are the only high-elevation toad in the Rocky Mountains and are an endangered species in Colorado. They live at elevations from 7,500 to 12,000 feet, just below tree line, and hibernate beneath the snow for six to eight months of the year. Researchers say that when the toads are stressed, they release a secretion that smells similar to peanut butter.
The toads were once abundant, even sitting under Buena Vista lamp posts at night in the 1960s to feast on insects that swarmed to the light, according to historical articles reviewed by CPW. Then the fungus came, killing off thousands of the tiny creatures in the 1980s and 1990s.
The fungus – Batrachochytrium dendrobatidis – is blamed for the death of amphibians all over the world, including in Australia, Asia and South America. Aquatic biologists say the toads lived in Colorado before humans and are an important part of the high-elevation ecosystem, where they eat bugs and serve as food for snakes, birds and weasels.
In Colorado, some transplanted tadpoles have received antifungal bacterial baths before they are packed into plastic bags and released into mountain bogs and ponds. The wash is called “purple rain” because of its lavender tint.
In one project, University of Colorado researchers injected boreal toads with either a spot of pink or green dye, visible through amphibian skin when they held a toad up to the sunlight. Green-spotted toads got the antifungal bath, while pink-spotted ones did not. Then they tried to capture the toads the following summer, searching for them in a pond above Buena Vista, to see whether they were infected with the deadly fungus.
A “Boreal Toad Recovery Team,” which includes biologists from Colorado, New Mexico, Utah and Wyoming, has been working to save the toads for 20 years.
“The boreal toad is a truly unique and resilient amphibian,” said Cammack, calling the discovery of the new tadpoles a monumental day in his career. “We are up at 11,500 feet, at timberline practically. They gut out big winters covered by multiple feet of snow and experience only three to four months of warm growing season.”
