The volunteers of FrogWatch USA will track the frog and toad population in south Louisiana by making note of the croaks and choruses of various species and then uploading their findings into an online database researchers can access.

By studying amphibians, scientists can improve their understanding of environmental changes on the animal world.

"They’re kind of like the canary in the mine, amphibians," said volunteer Harriet Pooler, 59, of Baton Rouge. "If the canary’s not doing well, you know that your environment is not well. If the amphibians are not in a certain area or if you see them dying off or the frogs are coming in with too many legs, it’s an indicator of environmental issues."

Created by the Association of Zoos and Aquariums, FrogWatch USA is a "citizen science" program akin to the Audubon Society's Christmas Bird Count or Monarch Watch, which encourages non-scientists to monitor monarch butterfly populations.

For the second year, the Baton Rouge Zoo is training south Louisianians to join the program. FrogWatch volunteers are asked to find a frog habitat and listen for a few minutes twice a week.

"It can be a ditch in your backyard, it can be a city park, it can be a pasture if you live on farm land," said Darcy Tatsch, an animal technician at the Baton Rouge Zoo who is leading the FrogWatch classes. "It can be anywhere that has water for some or part of the year."

Most of the listening will take place at nightfall, when the male frogs begin calling out to potential mates.

"They are breeding where this water source is because they have to lay their eggs in water," Tatsch said. "We’re looking at breeding calls in animals. We want to know what populations are out there and still getting out there to reproduce."

Volunteers from across south Louisiana attended two training sessions at the Baton Rouge Zoo this month to hear specifics on the program and practice listening to the recordings of the calls of the 25 species of frogs living in the region. Each citizen-scientist received a CD of common frogs and toads.

There's the bell-like call of the green tree frog, Louisiana's state amphibian, and the fire alarm sound of the barking tree frog.

Lisa LeBlanc, 41, calls herself a "nature junkie" and participates in other citizen science programs from her home on seven acres in Tangipahoa Parish.

"I’m very into bird watching … and raise monarch butterflies. This is another layer," said LeBlanc. "I think it’s important because science is so underfunded, and we can be where scientists aren’t."

After moving from the northeastern U.S., Chris Hayes and his wife, Kirsten Dorans, both 30, heard loud choruses of frogs at their home in Slidell and became curious.

"We had never heard that before," Hayes said. "We didn’t know what types of frogs they were. I didn’t know why they were making noise at a particular time."

Both Hayes and Dorans have scientific backgrounds, and after researching the frogs, they decided to help and joined FrogWatch.

Scientists have found that one-third of the world's amphibian species are at risk of extinction. Because frogs have such porous skin, they react quickly to environmental changes, Tatsch said.

"A lot of that has to do with human impact, habitat loss, pollution, climate change," Tatsch said. "That is why FrogWatch was started."

In just a few minutes each week, these civilian scientists feel they can help researchers complete important work just by listening.

"I feel like we have all the answers, the earth has it all for us," said LeBlanc. "We just have to find it and understand it."