黃腹山雀 Periparus venustulus

A tiny luminous ball of feathers. Adult males have a glossy black head with white cheek and nape, gray wings, and a bright yellow belly; females have a gray cap, a white throat, and a duller yellow belly. Typically hops around in trees but often ventures onto the ground and into low bushes to forage. An irruptive species in its eastern winter range; can be abundant one year and absent the next.