Sunlight
streamed through the tree trunks as we meandered into the warming woods. The Ruffed
Grouse’s thumping faded into the distance as we left his territory. In its
place a loud, staccato drumming echoed through the hills, followed by the
wildly laughing cry of a Pileated Woodpecker. My ornithology professor
nicknamed pileateds the “monkeys of the Northwoods” due to their raucous, whinnying
calls.
Like
grouse, Pileated Woodpeckers are not daunted by our northern winters, and
maintain their mates and territories throughout the year. Activity has ramped
up recently, though, with the onset of spring and breeding season. Unlike the
melodious warblers who are singing their way north right now, woodpeckers use
drumming to attract a mate and defend a territory. “With such energy did he
hammer that his whole body shook and his wings quivered. He fairly hurled
himself wildly at it,” described the naturalist Ernest Waters Vickers in 1915. They
add to the pulse of the forest.
Woodpeckers
beat on trees for three main reasons: to forage for food, to excavate a nest
cavity, and to drum for communication. The first two are relatively quiet
affairs, done slowly and deliberately. The third is as loud as possible.
Woodpeckers prefer the resonant acoustics of a hollow trunk or branch on which
to drum—or a stove pipe or rain gutter—to make sure that their message gets
across loud and clear. Both male and females drum.
I’m
not sure who was drumming the beat we heard, but as we peered through the tree
trunks, one large bird swooped through the maze and landed low on a bole,
followed shortly by its mate. Then again, one swooped off and the other one
followed. Were they just searching for food together? Or performing their
mating dance? In 1908, Francis H. Allen witnessed their ritual,
“They
hopped up and down the trunk, frequently pecking at each other's bills
simultaneously, now on one side of the tree, now on the other…They hopped
backward and downward a great deal, and often they lifted and partly spread
their wings. Their motions were limber and undulating, marked by a certain
awkward grace.”
After
the thrill of their mating rituals come the more domestic duties. Pileated
Woodpeckers use their large, straight, chisel-like bill to excavate a new nest
hole each year. The male seems to do most of the excavation of oblong hole,
removing wood chips from the area as they go. Dense, mature forests tend to contain
the large, dead trees that they prefer. In young forests, when old, dead nest
trees are the tallest ones around, lightning can present a hazard to nesting
birds.
Although
there is a significant time investment – each cavity takes 3-6 weeks to
complete – woodpeckers will not reuse the hole in subsequent years. This
probably serves to protect the babies from parasites, or from mammalian
predators who might remember the location from year to year.
In
the years after the woodpeckers raise their brood of 3-5 young, a wide variety
of birds and mammals will use the abandoned cavities. Other woodpeckers, wood
ducks, bluebirds, flycatchers, owls, bats, squirrels, and pine martens all
benefit from pre-drilled cavities. This makes Pileated Woodpeckers a keystone species
for their crucial role in creating habitat.
The
pileated pair leap-frogged their way deeper into the forest, and we continued
hiking. Several times we noticed piles of fresh wood chips near the trail, and
looked up to find a tree trunk perforated by large, rectangular holes from the
woodpeckers’ foraging activities. Nest trees have no such tell-tale signs,
since the birds carry away all chips, nest debris, and feces that might give
away the location of eggs and babies to a nest predator.
These
days, it seems our Pileated Woodpeckers are having good luck with reproduction.
Hardly a day goes by when I don’t hear the “monkey of the Northwoods,” or catch
a glimpse of this striking black-and-white bird in its undulating flight. It
wasn’t always that way. Pileateds were considered rare in 1900s, due to habitat
loss and hunting. When the forests rebounded, so did the birds. I like the
sound of that.
For over 45 years, the Cable Natural
History Museum has served to connect you to the Northwoods. Come visit us in
Cable, WI! We are currently constructing our new exhibit: “Lake Alive!” which will
open May 1, 2015.
Find us on the web at
www.cablemuseum.org to learn more about our exhibits and programs. Discover us
on Facebook, or at our blogspot,
http://cablemuseumnaturalconnections.blogspot.com.
Photo by Larry Stone |
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