A video of a woodpecker, but who is doing the singing?

This is the Black-backed Woodpecker. I assume the singer is a warbler, but that is as far as my guessing goes. Once again the SaskBirders have come through. They tell me this is a Tennessee Warbler. 

For people like me who prefer to see the bird that is singing, here is a Tennessee Warbler I photographed in our yard a year ago in May.