The northern leopard frogs were singing a romantic tune — long, deep, growl-like croaks — on a recent spring night at the beaver pond in the Santa Fe Canyon Preserve.
Their call-and-response routine made Robert Findling happy.
“It gives me hope,”said Findling, director of conservation projects at The Nature Conservancy, which owns the east-side wetlands preserve off Upper Canyon Road. It means, he said, there’s probably a healthy population of the chatty amphibians.
But there wasn’t a decade ago.
As part of a larger effort to restore the 525-acre preserve to what it might have been like in pre-Spanish Colonial times — before a series of dams were built on the Santa Fe River for storage of water supplies to meet growing demand — The Nature Conservancy began to stock northern leopard tadpoles.
Beginning in 2012, the conservancy began using funds from a $15,000 Intel Corp. grant to release more than 1,000 tadpoles and some adult frogs into the ponds at the preserve.
The organization also purchased listening devices so staff could monitor the frogs’ progress — or lack of it.
Now, seven years later, things are looking up for the leopard frogs, based on the crooning sounds emanating from the marsh.
While the frogs are not considered endangered, they have to fight to survive. They have a host of predators: fish, snakes and raccoons. Chytridiomycosis, a fungus that affects their skin and halts their ability to breathe, also kills them off.
It doesn’t help when locals dump nonnative fish species, like goldfish, into area waterways, Findling said.
The frogs face other challenges. While female leopard frogs can lay at least 3,000 eggs in one birthing season, it is believed that only a fraction of the tadpoles survive.
The ones that do survive seem thrive at the preserve, a mix of open ponds and swampy marshes, thick with willows and cattails, that is fed by Santa Fe River flows. The site is perfect for the frogs, Findling said, because it provides cover for the amphibians, which prefer to be heard and not seen. Despite their size — only 4 inches — the frogs can jump up to 6 feet to avoid people and noisy predators.
The preserve is also a permanent or seasonal home to red-winged blackbirds (whose singing sometimes drowns out the frogs’ calls), blue herons, cutthroat trout, bull snakes and garter snakes.
The male frogs call out to let female frogs know they are looking to mate. They’re particularly loud now because mating season is in April and May.
Once a frog begins rhapsodizing, it usually doesn’t take long for others to respond, resulting in a froggy choral performance.
Female leopard frogs don’t make such noises, said Nature Conservancy herpetologist Bruce Christman, who helped stock the preserve years ago.
New Mexico is home to five native species of leopard frogs, he said. While he is not sure whether the preserve area ever was home to the northern leopard frog before 2010, he added, it’s the perfect environment for the species.
When people ask him why the northern leopard frog is important, Christman said, he replied: “Well, they eat mosquitoes and help control the insect population and provide prey for garter snakes and raccoons, among other animals. They are part of our ecosystem. And when you lose things from the ecosystem, you don’t know for sure what the larger impact is.”
Findling said Nature Conservancy staff members will continue to monitor the progress of the frogs in the Santa Fe Canyon Preserve as long as funding is available.
The overall preserve restoration project began in 2000, when Public Service Company of New Mexico donated the initial parcel to the conservancy. Seven years later, a developer agreed to contribute another 335 acres. The conservancy has built a popular 1.5-mile hiking loop with interpretive signage around the preserve. However, the site been closed to the public since early April because high water from ample spring mountain runoff has posed a risk to visitors.
The Nature Conservancy is a global nonprofit with a New Mexico branch headquartered in Santa Fe. The branch is celebrating its 40th anniversary this year and will be moving from its Marcy Street office to the Railyard in June, Findling said.