[EBB Sightings] Need Woodpecker Help

Two days ago in my Moraga yard, I briefly saw (from a distance) a 
heavily black and white striped bird that I think was either a 
Nuttall's or a Ladder-Backed Woodpecker working hard on cracking some 
goodies open on the branch of my mulberry tree. The bird flew off 
before I could get my binocs and zoom in on the head. Can anyone tell 
me which of the two types I most likely saw? (I'm somewhat new to 
birding.) Thanks so much.
Blaine in Moraga
BAnderson1234 at aol.com