Anyone who has spent time outdoors has heard the rapid-fire tapping of woodpeckers, especially in the spring as the birds excavate new nesting sites in local trees.
The Downy (Dryobates pubescens) and Nuttall’s (Dryobates nuttallii) woodpeckers along with the Northern flicker (Calaptes auratus) are the species making all the racket as they hammer into dead trunks and branches of cottonwoods, willows and other deciduous trees.
These three species of woodpecker common to Merced County (not counting acorn woodpecker populations) can strike wood with beak speeds of more than 20 miles per hour and hit their mark up to 30 times per second without giving themselves a concussion, sinking into a state overwhelming lassitude or even launching a major migraine as the wood chips fly.
Both males and females help create new nesting sites, an effort that takes between one and three weeks. Excavation begins with clearing a horizontal hole one to one-and-one-half inches wide and then turning down six to 12 inches to make the actual nest site, which is wider at the base than at the top.
Wood chips not discarded during early wood-pecking are used as lining on which eggs are laid and young woodpeckers hatch. After fledglings leave their nest weeks after hatching, the bottom of the nesting cavity is a gooey mess of droppings and molted down.
Researchers think the reason Downy and Nuttall’s woodpeckers labor to excavate a new nest every year has to do with the unhygienic state of former nesting cavities. (Flickers will sometimes use the same nest two years in a row, but rarely three).
The woodpeckers’ distain of housekeeping is a boon to many other critters seeking tree cavities suitable for nest building or shelter. In fact, holes created by woodpeckers are in high demand by secondary cavity-nesters and essential to healthy woodland ecosystems.
Tree swallows, western bluebirds and house wrens are not put off by the unkempt condition of woodchips at the bottom of an abandoned woodpecker nest. They simply build a new nest on top of the old one and move in.
Wood ducks are also in the secondary market as are certain mammals like bats, mice and some squirrels which may modify the size of the opening to a nest or the nest cavity itself to fit their needs.
Besides birds and mammals, insects and arachnids also use woodpecker holes for shelter, ambush-hides or honey making, in the case of European honey-bees.
When out and about observing wildlife, look for woodpeckers hammering away to create a home for a new generation of their own species this year and housing for other species in years to come.
The San Luis and Merced NWRs are open to visitors 365 days a year from about 1/2-hour before sunrise to about 1/2-hour after sunset. There is no charge to visit and the refuges offer auto tour routes and nature trails allowing visitors to explore the wildlife refuges. So free up some time and make a trip down to a refuge soon.
