Taxonomy
The Nuttall’s woodpecker is closely related to the ladder-backed woodpecker of Arizona, New Mexico, Texas, and Mexico. The Nuttall's likely evolved via allopatric speciation when the two species were separated into smaller ranges by dry climate during the Pleistocene glaciation. Hybrids of the two species exist but are rare.
Read more about this topic: Nuttall's Woodpecker