This one is a tough call. The upper back should be black as in this Photo, and a ladderback's is not. The breast is white with black spots whereas the ladderback frequently has a buffy breast. The problem is the red cap. Its in the wrong area. It should be at the back of the head! The ranges of these two birds do not cross much and this photo was taken in western California, the range of Nuttall's and not Ladderback's.