Every winter I get a few calls about an unfamiliar bird using suet feeders. This particular bird has distinctive markings, so it's usually easy to describe -- about 8 inches long, black and white with bold white wing bars, white rump, and a bright red forehead. Some have red throats (males), and others have white throats (females). And like woodpeckers, they fly in an undulating fashion and hitch they way up tree trunks.
Though most woodpeckers are primarily black and white, the prominent wing bars and red or white throat gives this one away. It's a yellow-bellied sapsucker. (Yes, there really is such a bird.)
Sapsuckers usually head south for the winter, so it's unusual to see them this far north in January. The mild weather we've experienced recently may explain the spate of sapsucker reports I've received the last few weeks.
Though some first time observers might argue the point, yellow-bellied sapsuckers do indeed have yellow bellies. But they are as pale as red-bellied woodpeckers' red bellies.
Though seldom heard during the winter, sapsuckers become easy to detect by ear in the spring. Their staccato drumming pattern is diagnostic.
Uncommon at the feeder
Because sapsuckers, like flickers, are migratory woodpeckers, they're uncommon feeder birds. In 20 years I've seen only a handful in my backyard during the winter months. But by April, sapsuckers return to northern deciduous and evergreen forests where they nest.
The male selects the nest tree, often the very same tree he used the year before. Both sexes then excavate the cavity, but the male does most of the work. The female conserves her energy for egg production.
More often than not, sapsuckers select a live aspen or poplar infected with a heart rot fungus. The fungus softens the inner heartwood and makes excavating the cavity less difficult. The hard outer wood is not affected by the fungus and protects the nest from predators such as raccoons that might try to tear open the cavity.
After as long as 19 days, the cavity is complete. The female then lays one white egg each day for five or six days. Both parents incubate the eggs for about 12 days. The male handles the night shift. During the day the male brings food to the nest for the female. After hatching, the nestlings remain in the nest for another 24 to 28 days. During that time the parents feed their young sap and a variety of insects. Sap accounts for as much as 20 percent of their diet.
Master the art
After young sapsuckers leave the nest, their primary job is to master the art of sapsucking. They stay with their parents and use the feeding stations the parents have already established. These stations are easy to recognize. Sapsuckers drill vertical and horizontal rows of sap "wells" along the trunks of a wide variety of trees. Sap wells have been observed on more than 275 species of both deciduous and coniferous trees.
Each well is about 1/4-inch in diameter and oozes a steady stream of sugary sap. Sapsuckers lap the sap up with their bristle-tipped tongues. The sap also attracts insects, so sapsuckers can meet most of their nutritional needs at sap wells.
Though they also eat a variety of insects and the cambium (live inner bark) of some trees, sapsuckers rely on a steady supply of sap to survive. They aggressively defend their sap trees from hummingbirds, warblers, squirrels, and any other critters that crave the sweet stuff.
Homeowners and orchardists sometimes curse sapsuckers for the harm they do to trees, but the damage is usually cosmetic. Healthy trees heal quickly; sapsucker populations are rarely high enough to cause major damage.
By summer's end juvenile sapsuckers are independent, and most head south with the adults. If you see any stragglers in your backyard this winter, offer suet or, on mild days, hummingbird nectar (one part sugar : four parts water).