Many kinds of wildlife will sample the sweet taste of tree sap when it’s easily available. Various woodpeckers will occasionally drill into bark to get access to the sap. But the four species of sapsuckers of North America are unique in their degree of specialization on this resource, regularly drilling rows of “sap wells” in trees and then returning to sip the sticky treat as it oozes out.
Three of the sapsuckers — Yellow-bellied, Red-naped, and Red-breasted — are common and widespread, collectively found from coast to coast. They are very close relatives, differing mainly in the amount of red on the head, and they were formerly lumped into one species. But the fourth, Williamson’s Sapsucker, is highly distinctive. A specialty of western mountains, it is uncommon and elusive, a prize for birders.
The breeding range of Williamson’s Sapsucker extends from southern British Columbia south to the mountains of southern California, northern Baja, northern Arizona, and central New Mexico. It winters in the southern part of this range and well south into Mexico. At all seasons it occurs mainly in the mountains, but a few show up at low elevations in migration and winter. Stray migrants have appeared east to Louisiana and the Great Lakes, and one once was found on Long Island, New York.
So, although the species is extremely rare east of the Great Plains, birders everywhere have reason to watch for it.