This Week's Creature Feature: This Bird's a Home-Wrecker

Downy woodpeckers’ handiwork provides nesting cavities for themselves and other birds, but don’t let your house become their home 
       Would you believe that during its spring breeding season, the innocuous-looking, six-inch downy woodpecker can be a home wrecker, targeting our houses?
      You bet it can, and for reasons far transcending its habitual foraging for insects lurking in tree trunks, small branches, weed stems and plant galls. The rhythmic drumming we hear on wood, metal and even vinyl siding is central to the springtime territorial, nesting and mate-attracting activities of downies and related woodpeckers. While other species such as hairy woodpeckers are known to hammer at siding, downies are plentiful around the Chesapeake and can be persistent culprits.
      Downy woodpeckers are with us year round. Their territory is vast, extending coast to coast and from the tree line in Canada and Alaska to the southernmost tips of Florida and California. Look for them in winter in our area amid flocks of nuthatches and chickadees.
      Like many North American woodpeckers, they’re black and white, blending in with their woodland surroundings. Males boast the more flamboyant colors, a telltale patch of red on the skull. You may spot downies at backyard feeders, at parks or in forested areas. While downies don’t sing songs, you may hear their whinnying call, with a high-pitched pik note and a string of hoarse, high notes that descend in pitch toward the end. 
      Springtime drumming on wood or metal is unmistakable. You’ll hear rapid strikes at a steady pace. When excavating in trees or wooden structures, downy woodpeckers make a slow, deliberate tapping, which serves to attract a mate to the site. Yet when building nests and roosting holes inside attics and walls of buildings, this diminutive creature can wreak havoc. Downies can make holes two inches in diameter and larger, extending through the siding and into the insulation or even the attic.
      As we found, those holes can let other creatures in, too. In our home in Odenton, bats flew in.
     What can beleaguered homeowners do when your house becomes the target of an avian assault? According to the Cornell Lab of Ornithology, there are things you can try. 
      First, inspect the house. Woodpeckers are more drawn to homes near wooded areas, to redwood and cedar than to composite wood, and to natural wood or to wood with an earth-toned stain. Lighter color aluminum and vinyl sidings are less likely to show woodpecker damage.
      Next fill and repair large roosting and nesting holes from previous years. Do this either well before or well after the late April to May breeding season for downy woodpeckers. After making sure there are no birds inside, cover the holes with screen or fill them with wood or putty.
      If your home is clearly attractive to downies, you can choose among many tried (and sometimes true) methods for deterring nuisance behaviors. Most methods require some degree of explanation to your neighbors — who, having heard what’s going down, may still think you a tad eccentric. 
      Then, you should hang on to your sense of humor and get to work.
      You can suspend plastic eyes strung on fishing line or a life-sized plastic owl with paper wings above the hole. For a more devious approach, try hanging a large, hairy plastic spider high above the hole so that it drops down in response to heavy vibrations. Windsocks or pinwheels may work, or reflective streamers, tape, aluminum foil or bright mylar balloons. You can try covering the hole with burlap or bird netting, pulling it taut at least three inches out from the siding so the birds cannot peck through it. (Close off openings on all sides so birds do not become trapped between the netting and the house.) 
        Sound deterrents include a system that broadcasts woodpecker distress calls followed by the call of a hawk.
       None of these methods deter woodpeckers all the time, researchers admit, though streamers seem to work best. 
       Regardless of what damage they can do, downy woodpeckers are what ecologists consider a “keystone species.” In an ecosystem, downies and other woodpeckers are the keystone at the top of the arch. Remove that keystone, and the arch collapses.
       Downies build new nesting cavities annually, providing a valuable service to the 40-plus other species of birds other than woodpeckers that rely upon abandoned woodpecker cavities for housing.