Wood frogs to me are another sign of spring.
These frogs are the first on the pond, and can even be heard calling before the ice has fully melted off the pond. These are some pretty cool frogs, super distinct looking, and I would commonly find juvenile wood frogs hopping around the forest floor while I would be doing field work. If you want to be able to identify them in the field.
Check out the wikipedia page for them, it has a great example of a breeding call (under habitat):
I am working on finding a photo still, but hopefully I can get one to you soon, even if I gotta go and get it myself 🙂
UPDATE: GOT A PICTURE UP-CHECK IT OUT- species page found under amphibians heading at top of blog site.