Just as the spring peepers are winding down (early May), the gray tree frogs are winding up!
There are two species of gray tree frog -- common and Cope's -- but you can't tell them apart by looking at them (you need a DNA test), so I'm going to just call them gray tree frogs.
Some gray tree frogs are actually gray, but many are slightly green, and some are BRIGHT green. They make a sound like a very loud cricket chirp.
Gray tree frogs seem quite unafraid of people, and if you pick one up, it's hard to get it to leave you because it wants to hop UP your arm (like climbing up a tree?) and with those sticky toe pads, it can hop right up your shirt and onto your head!
A noisy yardful of tree frogs (With a green frog's "glunk" at 00:20)