Williamson's Sapsucker
Sphyrapicus thyroideus
Visual Identification
Appearance
Williamson's Sapsuckers exhibit striking sexual dimorphism. Males are predominantly black with a yellow belly, white wing patch, and red throat. Their back features a distinctive white rump and central white stripe.
Males and females are so unalike that they were originally thought to be two different species. Females share the yellow belly patch, although theirs is much smaller in size. A small black patch marks the upper breast, but otherwise, their plumage is mottled with white and brownish-black barring, apart from a solid white rump and a brown head with faint lighter streaks.
Both sexes have black bills and legs, with males showing more contrast in their plumage compared to the cryptic coloration of females. Juveniles of both sexes resemble adults, although their markings are duller and less clearly defined.
Size
Length
21cm to 25cm
Wingspan
43cm to 46cm
Weight
44g to 66g
Habitat and Distribution
Habitats
Woodland
Garden
Wetland
Coastal
Urban
Farmland
Grassland
Desert
Tundra
Rainforest
Mountain
Savanna
Distribution
Williamson's Sapsuckers inhabit montane conifer forests across western North America, from British Columbia to northern Mexico. They show a preference for mature stands of pine, fir, and aspen.
During the breeding season, they are found at higher elevations in the Rocky Mountains and the Sierra Nevada. In winter, some populations move to lower elevations or slightly southward but remain within forested areas.
Elevation Range
1,200 to 3,500 meters
Climate zones
Temperate, Subarctic
Distribution Map
This map gives you a rough idea of where you might spot a Williamson's Sapsucker. The coloured areas show countries where these birds have been seen.
A few things to keep in mind:
- Birds might not be everywhere in the coloured areas, for example, they may be present around the coast of that country
- Where birds live can change with seasons and available food
- This map is quite simple - it doesn't show exact locations
We're working on making our maps even better! Soon, we hope to show you:
- More detailed maps for bigger countries, including state and region
- How birds move around during different seasons
Distribution by Region
Behaviour and Ecology
Bird Attributes
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Share your thoughtsBird Attributes Explained
Our bird attributes system rates various aspects of a bird's capabilities on a scale of 0-100, based on data from field observations, scientific studies, and expert knowledge.
Attribute Categories:
- Agility: Manoeuvrability, speed, and grace in flight or movement.
- Strength: Physical power, often correlating with size and hunting abilities.
- Adaptability: Ability to thrive in various environments or changing conditions.
- Aggressiveness: Territorial behaviour and assertiveness, particularly during breeding seasons.
- Endurance: Stamina, often seen in migration patterns or foraging behaviours.
Understanding the Ratings:
- 0-20: Very Low
- 21-40: Low
- 41-60: Average
- 61-80: High
- 81-100: Very High
Remember, these attributes are relative to other bird species and don't necessarily indicate superiority.
Hover over the icon next to each attribute for more information.
Tap the icon next to each attribute for more information.
Agility
Reflects the bird's manoeuvrability, speed, and grace in flight or movement.
Williamson's Sapsuckers display impressive agility, manoeuvring adeptly through dense conifer forests. Their ability to perform slow, floating display flights and precisely drill sap wells demonstrates exceptional aerial and stationary control.
Strength
Indicates the bird's physical power, often correlating with size and hunting abilities.
While not exceptionally strong for their size, these woodpeckers possess sufficient strength to excavate nesting cavities in dead or diseased trees and drill numerous sap wells. Their strength is specialised for their feeding and nesting behaviours.
Adaptability
Represents the bird's ability to thrive in various environments or changing conditions.
These birds show notable adaptability, inhabiting a range of montane conifer forests and adjusting their elevation seasonally. Their ability to utilise different food sources (sap, insects, and occasionally fruits) further demonstrates their adaptiveness.
Aggressiveness
Measures the bird's territorial behaviour and assertiveness, particularly during breeding seasons.
Williamson's Sapsuckers exhibit considerable aggressiveness when defending their sap wells from other birds. This territorial behaviour, combined with their competitive nature during breeding season, indicates a relatively high aggression level.
Endurance
Reflects the bird's stamina, often seen in migration patterns or foraging behaviours.
Their endurance is evidenced by their ability to maintain and defend sap wells, which requires consistent effort. The species' short-distance migratory behaviour and their capacity to thrive in challenging montane environments also suggest moderate endurance.
Diet
Williamson's Sapsuckers primarily feed on tree sap, which they obtain by drilling rows of small holes in conifers. The inner moist bark layer of a tree trunk, known as phloem, is also important in their diet.
Ants, aphids, and beetles are also eaten, picked off the surface of the bark of a tree, or extracted, coated in sap, from the wells they have drilled.
In winter, fruits and seeds become more important, with berries and juniper, pine, and madrone among the most popular foods.
Behaviour
Williamson's Sapsuckers are known for their systematic sap-feeding behavior, drilling neat rows of holes in conifer trees. They defend these sap wells aggressively from other birds.
During courtship, males perform slow, floating display flights to attract females.
Vocalisation
Williamson's Sapsuckers have a relatively quiet call, a sharp 'chuck' or 'kyik'. Their drumming is distinctive, starting slow and accelerating to a rapid roll. During territorial disputes, they may produce a harsh, chattering series of notes.
They also use drumming to communicate, with a series of rapid taps, followed by three or four rhythmic, slower beats.
Nesting & Breeding
Breeding occurs from late April to July. Males initiate courtship with aerial displays and drumming to attract females. Pairs form monogamous bonds for the breeding season.
Nests are excavated in dead or diseased trees, typically at heights of 5-18 meters. Inside the chamber, a shallow layer of wood chippings is used as a lining, with no additional material added. The female lays 4-6 white eggs.
Both parents incubate the eggs for about 12-14 days. Nestlings fledge after 25-29 days, with parents continuing to feed them for several weeks post-fledging.
Conservation and Status
Global Conservation Status
While currently listed as Least Concern, Williamson's Sapsuckers face threats from habitat loss due to logging and climate change.
Conservation efforts focus on protecting mature conifer forests and maintaining snags for nesting sites.
Birdwatching Tips
- Look for their distinctive sap wells on conifer trees
- Listen for their sharp 'chuck' call or rapid drumming
- Observe tree trunks carefully, as their plumage blends well with bark
- In the US, focus on montane conifer forests of the western states
Additional Information
Quick Facts
Predators
Did You Know?
- Williamson's Sapsucker was named after Lieutenant Robert Stockton Williamson, who led a Pacific Railroad Survey expedition.
- They are the most sexually dimorphic of all North American woodpeckers.
- Their sap wells are used by other species, including hummingbirds and insects.
Similar Birds
References
- 1
website: BirdLife International. 2016. Sphyrapicus thyroideus. The IUCN Red List of Threatened Species 2016: e.T22680877A92884201.
View source - 3
report, 2007: Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven
- 2
website, 2022: Partners in Flight
View source
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