Pecking Order

At this time of year, the bare branches of winter reveal secrets unseen in summer’s leafy canopy. It’s a good time to see where nature’s drilling crews, the woodpeckers, have done their work.

There are seven species of woodpecker in Connecticut, and they all excavate cavities in trees to nest. Because of habitat loss, one of them, the Red-headed Woodpecker (Melanerpes erythrocephalus), is a Connecticut Department of Energy and Environmental Protection listed endangered species. Farmland, with groves of mature trees in old fields, and wooded swamps are decreasing. Competition for nest cavities with European Starlings (Sturnus vulgaris), a non-native species that outcompetes and displaces this woodpecker, is also a factor. Try to discourage starlings from using nest boxes and cavities.

Most species of woodpeckers excavate a new nest cavity each year, usually in a dead tree or in a dead branch of a living tree. You can often tell the woodpecker species by the size of the entrance hole, which is based on the size of the bird.

The Downy Woodpecker (Picoides pubescens), our smallest species, excavates a round hole 1 to 1.5 inches (3.8 centimeters) across. Its slightly larger cousin, the Hairy Woodpecker (Leuconotopicus villosus), makes a hole that is 2 inches (5 centimeters) in diameter. Even though Downy and Hairy Woodpeckers often live in the same forest habitat, they don’t compete with each other. In this niche partitioning, Downies hunt for sleeping insects in small crevices and will often crawl out on small branches, whereas Hairies peck more deeply into the bark along the larger trunk for wood-boring insects and their larvae. Here’s a video of a female Downy feeding her young in New York’s Central Park.

Yellow-bellied Sapsuckers (Sphyrapicus varius) chisel out a nest hole that is the same size as that of a Downy Woodpecker. But there is an easy indicator that they have been around. If you find rows of small, horizontal holes in a tree, you’ve found where a sapsucker has been. They usually create these drill wells in trees with sap that has a high sugar content, like maples and birches, and later will return to lick up the sap (they actually don’t suck sap). Maybe this bird should be called the Yellow-bellied Saplicker? They lick sap year-round, but will switch to a higher protein insect diet in summer.

Unlike most woodpeckers, Yellow-bellied Sapsuckers prefer to nest in live trees, especially the soft wood of Big-toothed Aspen (Populus grandidentata). Sapsuckers help other birds too. Ruby-throated Hummingbirds (Archilochus colubris) depend heavily on sapsucker drill wells as they migrate north in the spring.

The Red-bellied Woodpecker (Melanerpes carolinus), originally a bird of the southern United States, has moved into Connecticut in the last 50 years. Its nest hole is about 2.5 inches (6.3 centimeters) in diameter. Interestingly, this bird drills acorns and other nuts into bark and will later return to feed on its cache.

The Northern Flicker (Colaptes auratus), Connecticut’s second largest woodpecker, chisels out a nest hole with a diameter of 3 inches (7.6 centimeters). Unlike most woodpeckers, flickers often return to a successful nest site in later years. I once found an active flicker nest. The pair had chosen their nest site well. Just above the entrance hole was a bracket fungus, which created a nice canopy to shield the cavity from harsh weather. I’ll bet that pair has returned year after year.

The last, but certainly not least, woodpecker species is the largest in North America—the Pileated Woodpecker (Dryocopus pileatus). A larger woodpecker, the Ivory-billed Woodpecker (Campephilus principalis), is likely now extinct.

Pileated Woodpeckers create a round entrance hole that is 3 to 4 inches (7.6 to 10 centimeters) across. Most people think that the large, 4 inch by 6 inch (10 by 15.2 centimeter) rectangular holes that Pileated Woodpeckers make are nest holes. They are actually the woodpecker’s excavations to reach its favorite food: Black Carpenter Ants (Camponotus pennsylvanicus). Pileated Woodpeckers need a mature forest habitat of 150 to 200 acres.

Woodpecker cavities are important nesting and roosting sites for other wildlife too. Animals that use woodpecker cavities include the Deer Mouse (Peromyscus maniculatus), White-breasted Nuthatch (Sitta carolinensis), Eastern Gray Squirrel (Sciurus carolinensis), American Red Squirrel (Tamiasciurus hudsonicus), Southern Flying Squirrel (Glaucomys volans),Northern Flying Squirrel (Glaucomys sabrinus), Eastern Screech Owl (Megascops asio), and American Kestrel (Falco sparverius).

Did you know that you can create woodpecker habitat in your yard? Where I live, we’ve had some severe storms in the last few years that have resulted in a lot of snags and downed trees. I’ve also lost six American Ash trees (Fraxinus americana) in my yard from the Emerald Ash Borer (Agrilus planipennis). As long as the trees aren’t in any danger of falling on someone, you can create amazing wildlife habitat just by leaving snags in your yard. I had the tree company remove the top of each tree, but limb up and leave the bottom 20 feet (6 meters). All the insects and other decomposers tunneling into the bark and wood have “set the dinner table” for a whole host of woodpeckers.

Woodpecker nest box plans that you can make to attract these amazing birds to your yard are available online. Also, keep track of any woodpecker cavities you find near you and see what might use them this spring. You can install a trail camera and point it toward that hole. You might just be surprised what you see.