Local frog watchers find amphibians absolutely 'ribbetting'

[faze]

Date: Apr 12, 2004 - 01:04 PM
by Meredith Hooker
Staff Writer
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Apr. 7, 2004
Groups comb area creeks, parks to
collect data on
indigenous species

After the sun sets, Sligo Creek Park becomes a hotbed of activity for an amorous amphibian population from March through the summer--but they may not know people are listening.

The mating calls of the frogs can be heard from the banks as they breed from about a half-hour after sunset and well into the evening. And about 25 local frog watchers are documenting those calls and identifying species indigenous to the area for Frogwatch USA.

Frogwatch USA is a long-term monitoring program managed by the National Wildlife Federation and the U.S. Geological Survey, which is designed to collect data about the frog and toad population in the United States and promote an appreciation for the diversity of frog and toad species. It has been in place since 1999.

Maryland is one of the 10 most active amphibian states, according to data from the National Wildlife Federation.

This is the first year that the local environmental group Friends of Sligo Creek has participated in the program, said Michelle O'Herron, the organization's Natural History Committee chairwoman. "We were looking for something fun for kids to do" and wanted to help with the inventory of native species in the park, O'Herron said.

In general, there has been a decline in amphibian wildlife, O'Herron said, and no one is quite sure why. Frog watching helps researchers determine the presence or absence of amphibians over time in a particular area, she said.

More than 200 amphibian species around the world have experienced recent population declines, according to the National Wildlife Federation. Amphibians are an indicator of ecosystem health, and the decline of frogs and toads may indicate a decline in the health of the environment, according to the federation. Amphibians' porous skin makes them sensitive to the environment and its pollutants, which is why monitoring the amphibians is important.

Frog watchers are monitoring between eight to 10 sites between the source of Sligo Creek near University Boulevard in Wheaton, all the way down to New Hampshire Avenue and East West Highway in Takoma Park, said Karen Nelson, who is coordinating the program for Friends of Sligo Creek, making sure the entire creek could be monitored by frog watchers.

But it's not frog watching as much as it is frog listening. Before going out in the evening, frog watchers log onto www.enature.com and listen to the calls of the 13 different species that could be in the park. Then the frog watchers go to their designated areas along the creek bed to listen for them, Nelson said. Frog watchers can monitor their sites as often as they wish.

Some frog watchers may not be hearing any calls because some sites along the creek are not good for breeding.

Prime breeding sites are in the creek's headwaters near University Boulevard, Nelson said, and in retention ponds along the creek. It's necessary for the frogs to have slow moving or standing water to breed and lay their eggs, she said.

Last summer, a habitat pond near Dennis Avenue in Wheaton was a prime site for frog activity, Nelson said. "I saw tons there. Well, I heard them."

Right now, four major frog species can be heard singing a chorus in the park after hours. "They're all really distinct," Nelson said.

There are the spring peepers, who--naturally--peep. The American toads trill. The wood frogs sound like ducks quacking and the American bullfrogs sound like they're emitting low, rumbling snores.

Other common species that may be identified throughout mating season include Fowler's toads, gray treefrogs, green frogs and pickerel frogs, Nelson said.

It is up to frog watchers to determine how often to monitor their sites along the creek, following protocol designated on the Frogwatch Web site. When they make their observations, they take data sheets to record what they hear, a flashlight, thermometer -- to verify that it is warmer than 35 degrees -- and a watch. Frog watchers should listen to calls for three minutes, then record the intensities of the calls of species heard, according to protocol detailed on the Frogwatch Web site.

After observing their sites, frog watchers submit their data online to the Frogwatch USA Web site.

Learn more about the Frogwatch USA program and how to become a participant at www.frogwatch.org.