Is the bird's head that of:
a. A Cuban Green Woodpecker.
b. A Flameback Woodpecker from Asia
c. Another species of woodpecker, going undercover.
I decided to ask Molly Shields, who should know -- she designed the cover for Schiffer Publishing.
Molly says: "I had fun working on this cover! I got the image from a Cuban stamp... a Cuban Green Woodpecker, Xiphidiopicus percussus."
More about the Cuban Green Woodpecker here. (The photo in the link is by Michael J. Good of the Caribbean Conservation Trust, the leader on my Cuba trip three years ago.)
Below: Earl Poole's drawing of the Cuban Green Woodpecker from Bond's Birds of the West Indies (1936 first edition).