"When peepers sing..."

Hello,
Can anyone tell me anything about this phrase? I am wondering what kind of bird they mean and the origin of the saying...

"When peepers sing loud and long and late, the weather will cooperate."

Thank you!
Lorie

I'll look and see if I can find this one under weather-related sayings. One thing I am wondering about is whether "peepers" refers to birds or crickets.

This is one of those occasions when we need a specialist. (Do not trust dictionaries on this one.) The quotation refers to an amphibian, either the tree frog or a small aquatic frog. Each species sings long and loudly in the spring, the tree frog at night and the aquatic peeper during the day (and perhaps at night--I never spent my nights near their habitat). Each species is sometimes known as a Spring Peeper. You probably know that amphibians, especially frogs, have been hard hit by environmental degradation. Aquatic peepers may have become so scarce that you may never hear one. But I have no doubt that everyone reading this has heard tree frogs aplenty. Strangely enough, they live in trees, so you may have thought you were hearing an insect. SS