The department says there's been a documented worldwide decline in the population of frog, toads and other amphibians since the 1980s. It says amphibians may be disappearing because of habitat loss, pollution, disease and collection.
The state says it conducts the surveys with volunteer observers along a system of 200 survey routes. They're visited three times during spring when frogs and toads breed. Observers listen for calling frogs and toads at each site.
