Web Analytics
The Ivory Bill·Birds·Cavity Makers

Williamson’s Sapsuckers, Sphyrapicus thyroideus

Williamson's sapsuckers foraging on a tree trunk in a forest
Williamson’s Sapsuckers breed in montane forests in the western United States and parts of southwestern Canada from late April to early July. They are commonly found in mature coniferous and mixed forests, which are characterized by large trees such as pines and firs, where sap and insects are abundant during the breeding season.

They forage in forested habitats, particularly on trees with visible sap wells, for sap, ants, beetles, wasps, and caterpillars. They may also feed on fruits and berries.

Williamson’s Sapsuckers have specialized feeding habits that involve drilling neat rows of sap wells in the bark of trees, primarily in conifers, to access the sap and attract insects. They have a unique ability to excavate deep into the tree bark to reach their food sources.

Courtship involves a combination of drumming, calling, and display flights. Males perform elaborate displays that include wing spreading and head bobbing to attract females. Courtship often occurs near potential nesting sites.

Both males and females use their strong bills to chip away wood, creating cavities with deep chambers in trunks of dead or dying trees, typically in coniferous forests. These cavities are usually located between 3 to 15 meters above the ground. No additional materials are used for lining the nest cavity leaving only wood chips at the bottom.
Egg laying occurs in late spring, with the female laying 4 to 7 white eggs. Incubation lasts about 12 to 13 days and is shared by both parents. Upon hatching, both parents feed the chicks a diet of insects and sap.

Chicks learn to forage under the careful guidance of the adults, who demonstrate how to access sap wells and capture insects. As they develop, the chicks practice pecking and drilling techniques but remain vulnerable to predators and harsh weather conditions.

Chick fledging occurs about 25 to 29 days after hatching. Continued adult guidance is crucial as fledglings learn to become more proficient at foraging. Their diet evolves to include a greater variety of insects and sap.

Williamson’s Sapsuckers are partial migrants. They migrate in the fall, traveling short to moderate distances to wintering grounds in lower elevation forests and woodlands in the southwestern United States and northern Mexico.

Wintering habitats include oak woodlands, pinyon-juniper woodlands, and riparian areas. They forage for sap from deciduous trees, fruits, and insects.

They leave their wintering grounds in early spring, typically returning north to their breeding grounds from late March to early May.