Monday, March 9, 2009

Chorus Frogs

Spring is here! Maybe not officially, but don't tell the frogs. Temperatures were in the near 70's on Sunday, and the chorus frogs (Pseudacris triseriata) were singing full tilt in the wet areas around the ice skating ponds. It's quite amazing - you can be surrounded by hundreds of frogs singing until your ears ring, and not see a single one! It took me almost 20 minutes of waiting before the frogs closest to me came back out and I could finally locate one. They usually call from the base of a clump of reeds or grasses:

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:

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