December 2025 Natural Mystery Answered

Although this sign was old and weathered, many of you recognized it right away. Congratulations to Ronnie Hartman, Haleigh Zeibol, Leah Darst, Blake Southard, Erin Anderson, and one anonymous naturalist for correctly identifying the species that made this sign and the behavior.

These are the feeding wells of a Yellow-bellied Sapsucker (Sphyrapicus varius).

Many of you pointed out the regular arrangement of the holes. Haleigh notes that the holes are arranged in a grid, while Ronnie and Leah described them as horizontal rows. 

Erin and others note that the sapsuckers “both simply drink the sap, as well as draw sap that attracts insects to then feed on the insects.” There is also some evidence that sapsuckers will forage for insects which they then dip into wells before eating or feeding to nestlings.

There are four species of sapsuckers, all endemic to North America, which leave similar looking sign. The Red-breasted Sapsucker is found along the Pacific Coast, from Alaska to California, and the Red-naped and Williamson's Sapsuckers are found across much of the West. The Yellow-bellied Sapsucker has the broadest range and is found across the east, and throughout much of Canada and Mexico. Some authorities consider the Red-breasted, Red-naped, and Yellow-bellied Sapsuckers to be color variations of a single species.

The wells created by sapsuckers are important for many other animals as well. Ruby-throated Hummingbirds (Archilochus colubris) in particular appear to associate closely with sapsuckers, building nests near sap wells, following sapsuckers around on the landscape, and perhaps even timing its migrations to coincide with those of sapsuckers

Congratulations again to Ronnie, Haleigh, Leah, Blake, and Erin for identifying these old sapsucker wells and sharing their insights with the rest of us.