Pretty little fellow. He might try, but may be unsuccessful, as NJ gets awful cold in winter. If I wanted to keep him, I might grab him one day, place him in an aquarium, feed him crickets from the pet shop, and place him back in the pond when it warms up in Spring. By next summer, there might be enough muck and dead plant matter on the bottom to support a Bullfrog (insulation and support), and more than likely, since he showed up, I imagine many more of his little friends will too in the future.

I do think I will try to move him to a local pond where I hear them, understanding that the pond is, probably, carrying all it can, already.
I am confident new ones will show up, trapped in the window wells, next Summer. They always have.