A Partnership That Works
Sapsuckers and Hummingbirds


Yellow-bellied Sapsucker photo by Ann Cook

The tiny holes drilled by this Yellow-bellied Sapsucker are an important source of sweet fluid for Ruby-throated Hummingbirds in early spring

People aren't the only ones who love sweet syrup! Yellow-bellied Sapsuckers time their migration to return north right when sap is running. These special woodpeckers tap little holes in a circle around the trunk or a higher limb. Then they come back over and over again to lap up the sap with their brushy tongues and to pick up insects that are drawn to the sweet liquid.

Eventually the trees make "scabs," closing off the holes. So the sapsuckers make another ring of holes right above or below the first ring. They might choose maple syrup if healthy maple trees didn't have such hard wood. Instead, they tap the sap in softer trees, especially aspens.

The Sapsucker Connection
Many other birds love sap and the insects that collect near it, but most don't have the beaks to get at it. Sapsucker holes are an important food source for at least 35 species of birds.

Sapsuckers winter in the southern United States. They are one of the first migrants to appear in northern states and provinces in early spring — right when sap is running strong. They migrate about two or three weeks before hummingbirds do. They often rest for a week or two in spots between their winter and summer homes. As they do, they make temporary feeding stations. Sapsuckers spend much of their time drilling holes, usually going back and forth working on two or three different tree branches at a time. One migrating sapsucker drilled 286 tiny holes in a pine tree in 9 1/2 hours one April day, providing a bounty of food for itself — and for other birds!

While sapsuckers are guarding and feeding at one set of holes, a host of other birds may visit their other sets of hole in search of sap and insects. Sapsuckers only drill holes during the spring and summer while sap is running. As sap dwindles, the sapsuckers turn to flying insects, ants, fruits, and nuts for food.

Hummingbirds in Pursuit

The first Ruby-throated Hummingbirds to return north in the spring, usually when weather is still cold, often depend on sapsucker holes for their food. Once enough flowers bloom, they no longer need to "get by with a little help from their friends."

Ruby-throated Hummingbirds have been seen actually following sapsuckers as these woodpeckers visit their sap trees. Do you think this may help the hummingbirds learn the location of these trees? As long ago as 1891, a scientist named Frank Bolles noticed that hummingbirds visit sapsucker holes more than any other birds. He saw them come to these holes throughout the summer, but especially in early spring. Experts who have analyzed sap say it is remarkably like flower nectar. Both contain sucrose and traces of amino acids. So sap is a perfect substitute for nectar in areas where few nectar-rich flowers are blooming and where sapsuckers live.

When two species associate closely with one another, benefiting at least one without harming either, the relationship is called symbiosis. Hummingbirds get an obvious food benefit from sapsuckers, but sapsuckers may also get help from the hummers.

Hummers Return the Favor
In northern Wisconsin one May, ornithologist Laura Erickson spent many hours studying some sapsucker trees. The woodpecker had drilled circles of holes in three different aspen branches for feeding. While the sapsucker fed or rested on one branch, Laura watched other birds
Ruby-crowned Kinglets, Cape May Warblers, Yellow-rumped Warblers and Eastern Phoebescome to the holes in the other two branches. Most of the time, two or three birds gorged themselves at each feeding spot. But whenever a hummingbird visited, it pugnaciously chased away any birds that happened to be thereexcept the sapsucker. While hummingbirds eat a lot of food compared to their body weight, they don't eat much compared to warblers and phoebes. Therefore, hummingbirds may be helping sapsuckers by defending the sapsucker's hole borings from other larger, hungrier species. It may be a partnership that works both ways!

Try This!
  • Using binoculars, look very carefully at the top branch tips of different kinds of trees. Do you see any with tiny insects swarming at the newly running sap? Can you find any birds up there?