**Description:** A small bird with a white face and blue-gray back; famous for its ability to walk down tree trunks head-first.
**Size & Weight:** 5.1–5.5 inches long. Weighs 0.6–1 oz.
**Sexual Dimorphism:** Males have a solid black cap; females have a lead-gray cap.
**Behavior:** They wedge nuts into tree bark and "hatch" them open using their sharp beaks. Known for a characteristic nasal "yank-yank" call.
**Habitat:** Mature deciduous and mixed forests; a year-round resident.