Mid-April means that the yellow-bellied sapsucker, one of our few migratory woodpeckers, is returning from its southern winter digs. First on the bird’s agenda? Drilling holes into the sapwood of trees—hemlock, aspen—to get at that sweet, sweet sap. Later in spring, the woodpeckers go for birch, maple, beech, and other hardwood trees. They create dozens and dozens of oozing holes, often in big trees that are already weak or wounded. These trees yield sweeter sap that flows more easily.
Sapsuckers suck sap. Obviously. But they also scarf up all the delicious insects attracted to the bounty that their tree tapping has unleashed: ants, beetles, hornets, wasps…yum! Of course, bugs benefit from the sap too. It’s an important source of food for the mourning cloak butterfly, one of the first butterflies to rise in the spring. Yellow-bellies are mostly happy to share: hummingbirds, finches, orioles, and kinglets all join the buffet a little later in spring. Even some small mammals will eat the sap. (Once it ferments, everyone gets a little buzzed.)
A hard-working yellow-bellied sapsucker can drill about 20 sap wells per day. But by May, it’s time to chisel out a home. Sapsuckers usually pick trees infected with heart-rot—they’re easier to excavate. The male bird of a pair bond will take about three weeks to carve out a nest hole, as deep as 25 cm, and later, help incubate the eggs at night.
Once baby yellow-bellies have fledged, and the family has left that particular nest hole for good, other creatures move in. It’s so roomy that it makes a great home for big brown bats, tree swallows, and flying squirrels.