For whatever reason (where I live, my birding habits), I just don't see the number of sapsuckers that I used to. I have seen very few Red-naped Sapsuckers in the last several years, which is why I come to you now.
As you probably know, Red-naped and Red-breasted Sapsuckers interbreed frequently, and southern California gets a fair number of these hybrids. Backcrossing of hybrids with full-blooded Red-naped and Red-breasted certainly happens, which can lead to strange-looking birds. Recently in Ventura County, I had 6 sapsuckers in one set of pepper trees...2 hybrids, 2 Red-breasted, a Yellow-bellied with a broken wing, and this bird.
This bird's left side did not have quite as much red breaking into the white moustachial. Also odd was the color of the bird's nape; it was noticeably duller than the color of the crown and throat, but I don't think this is particularly problematic for Red-naped.
In the field I was leaning towards calling this bird a mostly Red-naped individual with some recent Red-breasted genes, but now I am leaning more toward an aberrant Red-naped. If you have experience in this realm, please leave a comment below, I'm curious to see what people think of these red-tinted cheeks. Anyways, a very sharp-looking and confiding bird.
Here is a more straightforward bird, present at the same site. I thought it was a Red-naped until I got an unobstructed view of the nape; it had a continuous red stripe running all the way from the forecrown to the base of it's neck, like a male Red-bellied Woodpecker. Nice-looking hybrid. The other hybrid present looked much more similar to a Red-breasted. All photos are from Canada Larga Road in Ventura County, CA.