The ponds, creeks and nature trails in St. Charles could soon see more visitors listening intently to the sounds in the air, trying to identify the ribbits, croaks and grunts of frogs.
Identifying different types of frogs in the area helps a regional effort to track which varieties might be disappearing locally. Naturalists say it's important to identify vanishing species to determine overall environmental problems.
"Globally speaking, amphibians are in a decline," said Pam Otto, manager of nature programs and interpretive services at the St. Charles Park District. "They're very vulnerable to threats. If there's a problem with water, land or air, these are usually the guys that pick up on it."
The St. Charles Park District heads up Kane County's contribution to the Chicago Wilderness Habitat Project's frog identification program. The group — along with Chicago region of the National Audubon Society — keeps a database with information on species of frogs in the Chicago collar counties and northwest Indiana, and has been doing so for about a dozen years.
"This is done all around the world," said Karen Glennemeier, science director at the Audubon Chicago region.
Volunteers are trained by their local forest preserve or park district, and then on their own can listen for frog calls — which are unique to each species, she said. They can then input that information on the group's website.
St. Charles will offer its annual training Saturday at Hickory Knolls Discovery Center for anyone age 8 and older. At the training, volunteers will receive recordings with frog calls, instructions on what to do and when during the year to start listening depending on which species, Otto said.
There are about seven or eight species of frogs in the Kane County area, but about 13 throughout the Chicago region, Otto said.
"The good news is we haven't seen any big changes in the frog population," Glennemeier said of recent survey results. "The rare ones are still rare and the common ones are still common."
But that doesn't mean the area has always been in such good shape, she said. About 40 years ago, there used to be a common species of frog in Northern Illinois called the Northern Cricket Frog. Since then, the species has nearly disappeared.
"They think it's just due to climate changes," Glennemeier said of the frog, which likes a colder and wetter environment.
In that case, "there's not much we can do at the local level," she said, but in other cases, action can be taken.
Some frog species could be threatened by chemicals used to treat water and landscaping, building projects or diseases that only affect certain species, Glennemeier said, adding some of the problems could wind up hurting humans.
"Sometimes it's obvious; sometimes it's not," she said.
Why care about frogs? Besides identifying larger environmental issues that could also affect humans, Glennemeier said there's another, deeper reason.
"It's sad when we lose a species," she said. "They're part of the wonderful richness of life."
For more information, visit habitatproject.org or stcparks.org.