November's Bird of the Month

Williamson’s Sapsucker (Stryrapicus thyroideus); Chupasavia Oscuro (Spanish)

The male Williamson’s Sapsucker has a plumage that drastically departs from what I had known as the common black-white-red woodpecker color scheme while growing up in the Midwest. With its yellow breast, overall dark and somewhat iridescent upper body and white shoulder patch plus black and white facial patterning, all highlighted with a deep red throat, this bird flew up my personal favorite chart when I unexpectedly saw it for the first time in the mountains above my home in Santa Fe. As notable as the male is for its plumage, the real story of this species is the extraordinary difference in the appearance of the two sexes, which makes them the most sexually dichromatic woodpeckers in the world. The female, with a largely dull brownish body decorated by bars, black breast patch, and prominent yellow belly, can be easily dismissed as totally unrelated – indeed, as was the case when the two sexes were first reported as separate species in the 1850s; John Cassin for a female in 1852 and the Lt. Robert Williamson’s survey party for a male in 1855. It wasn’t until the 1875 when a naturalist, Henry Henshaw, saw the pair nesting in Colorado that the final corrected listing kept Cassin’s initial Stryrapicus (genus) thyrodeus (species) while dropping Picus williamsonii and underwriting Williamson’s Sapsucker as the common terminology.

Williamson’s Sapsuckers are migratory, moving from the Southwest to the Pacific northwest in the summer, while shifting south to winter into northern Mexico – with some year round presence in central New Mexico and Arizona. Red-naped Sapsuckers also occupy this extensive southwestern and inter-mountain seasonal range. (If you click on the sidebar link for the Red-naped Sapsucker, note the extreme similarity of the sexes when compared to that of the Williamson’s Sapsucker).

As the name implies, sapsuckers devour the sap produced by a tree after the bird has drilled holes through the bark. The birds focus on specific trees and repeatedly return to dip their beaks into the active reservoir not only to sample the sap and phloem, but also to eat insects (especially ants) that are drawn to the sticky residue.  Unlike the other woodpeckers in the Picidae family, which have sharp tongues to extract insects while probing subsurface, the tip of the sapsucker’s tongue has a bristle of hairs that collects sap by capillary action much as does a painter’s brush. As seen in the photo for a tree heavily targeted by the two species of sapsuckers in Santa Fe, the Williamson’s Sapsucker might be seen as a proud artist displaying his handiwork.

Williamson’s Sapsuckers are generally found above 5,000 feet elevation and breed in mixed-conifer mountain forests where the male excavates a cavity, preferably in a live aspen that has been softened by heart-rot fungi. Five to six eggs are laid in the May through June with incubation for close to two weeks. They mostly feed the nestlings ants and can be observed sharing their support roles, as seen in the attached photo. Fledging occurs about 30 days later. I have seen them with young at the Santa Fe Ski Basin near 10,000 feet elevation during the breeding season. Fall leads them to move south and to lower elevation. This is the time when one can find them at specific feeder tree locations in Santa Fe near 7,000 feet elevation.

Partner’s in Flight assesses the Williamson’s Sapsucker at low conservation concern where a roughly stable population has been reported since the mid-1960s. However, continued viability of the species is intimately tied to the health of mixed-coniferous forests. Large-scale logging plus massive fires, where forest diversity is strongly affected, are threats to the species – not to mention the overall changes to montane habitat that will result from climate change.

How you can help, right now

Audubon Arizona and Audubon New Mexico have joined forces to become Audubon Southwest.