Differences in Hairy Woodpecker belly feathers in the North Cascades

November 18, 2016
Burke Museum
Hairy woodpecker

Photo: Janet Horton

Hairy Woodpeckers can be found across the United States in areas with large trees, from sea level to about 6,500 feet. They use their narrow, strong bills to tap into trees for wood-boring insects, like beetles and ants. Insects make up majority of their diet. 

Next time you see a Hairy Woodpecker, make sure to notice its belly. Hairy Woodpeckers to the east of the North Cascades have white bellies and those to the west have brown. If you’re in the North Cascades, the mountain range that divides eastern and western Washington, its belly feathers may be either white, or brown… or a color that is neither white or brown but somewhere in between.

Six Hairy woodpecker specimens in the Burke collections

Brown-bellied Hairy Woodpeckers (left), white-bellied Hairy Woodpeckers (right). Probable hybrids (intermediate belly color) are shown in the center.
Photo: Burke Museum

The white-bellied eastern birds and the brown-bellied western birds overlap in the North Cascades region during the summer season—and interbreed—creating what is referred to as “a hybrid zone.” Within this zone, “mixed pair” matings  result in offspring that have an intermediate belly color.

Researchers from the Burke Museum’s Ornithology Division have recently discovered that the birds east and west of the North Cascades are also genetically quite different from one another. They are actively studying Hairy Woodpeckers from hybrid zones, such as the North Cascades, to further understand their genetic differences and to explore the implications of being hatched in a hybrid zone.

Brown-bellied Hairy Woodpeckers

Brown-bellied Hairy Woodpeckers (front) from the west of the North Cascades.
Photo: Burke Museum

White-bellied Hairy Woodpeckers

White-bellied Hairy Woodpeckers (front), from the east of the North Cascades.
Photo: Burke Museum

Museum specimens, like these Hairy Woodpeckers, are used to document existing biodiversity and are made available to researchers across the world in order to help us better understand our world and how to protect it for the future. 


Learn more about the North Cascades in the Burke Museum’s Wild Nearby exhibit open through April 9, 2017. 

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