Red-bellied Woodpecker

I was always intrigued by this bird’s name given the striking red nape, and then read this from Audubon.com—
But the Red-bellied Woodpecker retains one element of mystery: its name. Why call it “red-bellied”?
Whoever first named the species must have had a wry sense of humor. For, on this strikingly patterned bird,
the last thing you would likely notice is a slight blush of rose on its lower belly.