Marin IJ Articles
October 6, 2018
The name says it all: woodpecker. These colorful black and white birds with, often, red on their heads validate their name by drilling into trees, utility poles and occasionally house siding. Their thick skulls and tough neck muscles make it possible to repeatedly hammer into wood without suffering internal injury. Their long tongue can dislodge insects from crevices, and then curl back inside. Zygodactyl feet and a clasping toe help them climb as they look for insects, berries, nuts and seeds. And, a stiff tail helps with balance.
Some have specialized talents.
The fascinating acorn woodpeckers work in cooperative colonies, drilling into thick bark and dead trees to create granaries where they store one acorn a hole. They don’t harm living trees. Some granaries reportedly contain more than 50,000 acorns.
The eponymous sapsuckers, a woodpecker with similar black, white and red markings and red chest bleeding to yellow, bore into trees to feed on sap. Flickers, a beautiful multicolored woodpecker with speckling on its breast and red markings on its face, feeds on ground insects, particularly ants.
Most woodpeckers help gardeners by consuming harmful insects; they rarely damage healthy trees. If damage occurs, it’s most likely from sapsuckers girdling a tree or branches with holes. To discourage them, wrap burlap or ¼-inch mesh hardware cloth around the drill site and beyond — otherwise, the bird will simply move nearby.
Woodpeckers don’t always pick trees, though. The birds can become a nuisance if they create acorn granaries beneath wooden shakes or shingles, drill for food, create nests and roosts, or drum on a house.
Woodpeckers are particularly fond of carpenter bee larvae, our native leafcutter bees and grass bagworms, so if these insects live in wooden siding, eaves or trim boards, it’s a woodpecker grocery store. Cedar and redwood siding, and rough-hewn veneer-type plywood is most vulnerable to pecking. A series of small holes in a row signals that woodpeckers have been shopping.
And, they might decide to stay a while. A round, large hole in the side of a house could be a woodpecker nest or roost hole. Although woodpeckers prefer dead trees or snags, some like soft cedar siding.
These holes typically occur in natural wood or dark-stained clapboard, board-and-batten or tongue-and-groove siding, and in shakes and shingles. When excavating, the clever woodpecker digs through the wood between two boards or abutting shingles and then hollows out an area in the insulation.
Clusters of shallow holes or dents as large as 1-inch across, on the other hand, are most likely the result of drumming.
Before breeding, woodpeckers proclaim their territory with repetitive tapping on the best resonating surface they can find. They might drum on trees, fascia boards, a metal gutter, rooftop ventilator or downspout. Drumming can be headache producing, but it is rarely damaging. The head banging stops once breeding begins.
Woodpeckers usually build nesting holes at the beginning of the breeding season in late April and May. They bore out roosting holes in late summer and fall in preparation for winter.
If woodpeckers become a nuisance, you can try to deter them.
Researchers at the Cornell Lab of Ornithology studied the effect of six deterrents: Plastic owls, reflective streamers, plastic eyes on fishing lines, roost boxes, suet feeders and a sound system broadcasting woodpecker distress calls followed by the call of a hawk. Of those, only the streamers worked with any consistency, but nothing worked all the time.
The most effective way to prevent building damage is to stretch bird-type netting from the eaves to a lower-point on the building — or on any flat surface prone to damage. Be sure the netting is taut, side openings are closed, and that it’s installed three inches out from the side.
Know, though, that all woodpeckers are protected under the Migratory Bird Treaty Act. Don’t hurt these beautiful, mostly helpful and rarely annoying creatures.