Chorus frogs sing in these ponds in the daytime, but at night the spring peepers take over. By mid-April the chorus frogs all head back to the forest, and we won't see or hear them again until next year, although if you pay VERY close attention, you might notice tiny chorus froglets, no bigger than your pinky nail, leaving the pond in May and June. If you have good speakers on your computer you might want to turn them down - these are tiny little frogs, but they're very LOUD!
The purpose of all of this noise is for male frogs to entice female frogs to choose them for breeding. Singing uses incredible amounts of energy for the male frog, and those that can sing loud and long are likely to be the most fit and healthy mates. The male frog clasps the female in "amplexus" and fertilizes the eggs as she lays them:
Freshly laid chorus frog eggs:
After being in the water for awhile, the clear egg jelly surrounding each egg expands, and the eggs orient themselves dark side up, making them hard to spot against the dark bottom of the pond: