It is the call of eight Eastern Gray Treefrogs (Hyla versicolor) that we rescued from our POOL last night. They were crawling up the sides but could not navigate the overhang.
Armed with a net and a flashlight, my girl and I helped them on their way. Later that night we could hear them further into the woodlands.
ADDED NOTE- 6pm :
We saved another frog today and got some pictures too.
The undersides of his inner legs are a brilliant GOLD color. I tried to make him move to snap a picture but he jumped away too fast into the woodlands