I didn't have time to look this up before but I did find a notation on albinism in Sooty Shearwater in the National Audubon Society's Encyclopedia of North American Birds by John K. Terres:
"A number of partial albinos reported; white most often on head and neck, although whole body may be pied"
There is no mention of albinism in Harrison's "Seabirds" nor is there an illustration of what a "pied" individual might look like. Rich Stallcup's "Ocean Birds of the Nearshore Pacific" mentions; "symmetrically leucistic birds occur rarely and have been mistaken for other species, even the flashy Cape Petrel (Daption capense). Although, the illustration of a Cape Petrel in "Seabirds" doesn't look at all like the bird we observed off the SMRE. It was certainly just an odd looking Sooty. Just wanted to share that.
I also forgot to mention that as we were looking for a lifer Tricolored Blackbird for Dave's friend from CO, we found a flock of mixed blackbirds near the intersection of Highway 1 and Black Road just east of Santa Maria which contained the Tri's and at least four female Yellow-headed Blackbirds.