Essay/Term paper: The downy woodpecker

Essay, term paper, research paper:  Science

The Downy Woodpecker


Habitat

Downies take home in the United States and southern Canada. They have been
recorded at elevations of up to 9,000 feet. The downies are not deep-forested
birds, preferring deciduous trees. Open woodlands, river groves, orchards,
swamps, farmland, and suburban backyards are all favorite haunts of the downy.
Downies will also nest in city parks. About the only place you won't find them
is deserts. The most attractive human dwelling sites are woodlands broken up by
logged patches in a waterside area. Downies also enjoy open shrubbery with
groves of young deciduous trees.

Call(s)

Like the hairy woodpecker, the downy beats a tattoo on a dry resonant
tree branch. This drumming is the downy's song, though they do make some vocal
noises. They have several single-syllable call notes which include tchick, an
aggressive social note; a tick and a tkhirrr, which are alarm notes. There is
also a location call, known as a "whinny", made up of a dozen or more tchicks
all strung together.

Scientific Names
The downy woodpecker's scientific name is Picoides pubescens. There
are also six particular downies with six particular scientific names all from
different regions of the United States and southern Canada which I have listed
below:

southern downy / Dryobates pubescens Gairdner's woodpecker / Gairdneri pubescens
Batchelder's woodpecker / Leucurus pubescens northern downy / Medianus pubescens
Nelson's downy / Nelsoni pubescens willow woodpecker / Turati pubescens

The downy woodpecker is sometimes reffered to as "little downy."

Behavior Towards Humans

The downy is unquestionably the friendliest woodpecker. A bird lover
in Wisconsin described downies at their feeding station: "The downies will back
down to the suet container on the basswood tree while I sit only a few feet away
on the patio. Even when I walk right up to them, most downies will not fly away,
but will simply scoot around the backside of the tree trunk and peek around to
see what I am doing. If I press them, they will hop up the backside of the tree
trunk and then fly to a higher branch.

Food
Besides being friendly, downy woodpeckers are our good friends for
another reason. Most of the insects they eat are considered destructive to man's
orchards and forest products. About 75% of their diet is made up of animal
matter gleaned from bark and crevices where insect larvae and eggs lie hidden.
While standing on that unique tripod of two legs and and a tail, downies hitch
up and down tree trunks in search of a whole laundry list of insect pests. With
their special chisel-like bills and horny, sticky tongues, downies are adept at
plucking out great numbers of beetle grubs, insect cocoons, or batches of insect
eggs. They also eat spiders, snails, ants, beetles, weevils, and caterpillars,
with other local insects included. 25% of a downy's diet are plants made up of
the berries of poison ivy, mountain ash, Virginia creeper, serviceberry, tupelo,
and dogwood. Downies also eat the seeds of oaks, apples, hornbeams, sumac,
hickory, and beach. Acorns, beachnuts, and walnuts are the particular favorites.

Dr. John Confer and his students at Ithaca College have studied the
downy woodpecker's use of goldenrod galls as a source of food. They discovered
the downy's little jackhammer is just the tool needed to drill a hole in the
side of the one to two inch goldenrod gall and extract the tiny grub contained
inside. In fact, Confer's studies show that the goldenrod grubs form an
important part of the woodpecker's winter diet.

Plumage

Tap, tap, tap! Tap, tap, tap! It is interesting how the downy woodpecker
props itself with those stiff tail feathers while clinging to the bark. The tail
relieves the birds weight. This unique tripod allows the downy to hop up the
tree trunk with ease, but it must back down in the same position, a more akward
motion.
The downy woodpecker gets its name of downy because of its soft fine
feathers. The downy, smallest of the woodpecker clan, is not even as big as a
robin. It is only about the size of the of a house sparrow at six inches tall.
The downy can be separated from all other woodpeckers ~ except the hairy ~ by
the broad, white strip down its back. The downy and the hairy are often confused
since their markings are quite similar. Both range across the same territory
except the lower southwest where the downy is less often seen. There are really
only two ways to distinguish the downy and the hairy. (1) Look at the bill of
the two birds. The downy will have a much shorter, stubbier bill. (2) The downy
is about 2/3 the size of the hairy. That is another good clue to look for.
The downy is most likely to be the one that you see at the feeder, since
the hairy keeps more to the forest than the downy. However, both will feed at
feeders in the winter months, on suet especially.
The tail, wings, and back of both the downy and hairy woodpeckers have a
black hue intermingled with white spots. A black cap adorns each, below which
there is a white stripe. A small scarlet patch appears on the lower~back of the
head. Another black stripe is below this. The downies have barred outer tail
feathers not found on the hairies.

Courtship

Regardless of the elevation, downy woodpeckers begin thinking about
nesting earlier than most birds and several months before they actually nest.
After spending the winter alone, the downies seem to come to life in early
February, moving more quickly and taking more interest in their own species.
Their normal tap, tap, tap becomes a quite different unbroken
trrrrrrrrrrrrrrrrrrrrrrrr, lasting several seconds. The tapping is no longer
simply an effort to find food but a means of communicating to other downies that
this is "my" territory. It is also the first attempt to attract a mate. Both
sexes drum. So early does this drumming begin that it is not unusual to hear it
on sub-zero mornings.
Some ornithologists believe that downy woodpeckers retain the same mate
as long as they live. In this case, all the pair has to do in the spring is to
renew their pair bonds. This fidelity, however, seems to be a result of an
attachment to the nesting site rather than between the birds.
After the drumming has united the pair, the actual courtship begins with
a curious dance or "weaving" action by both sexes. With their neck stretched out
and bill pointed in line with their head and body from side to side balancing on
the tips of their tail. Their entire body is elongated. There is also a lot of
flitting and chasing from one branch to another, and more waving and weaving of
head and body. Sometimes with wing and tail feathers spread. Considerable
chattering accompanies these gyrations.

Nesting

Sometime during the courting period the actual selection of a nesting
cavity occurs. The female is usually, though not always, the dominant bird and
selects the nesting site. Ounce selected, both birds dig the hole. Downies will
characteristically place the nesting cavity 3-50 feet above the ground on the
underside of an exposed dead limb. The pair will alternate digging because only
one bird at a time can fit into the cavity. As the hole is cut deeper, the bird
working may disappear into the hole and remain out of sight for 15-20 minutes,
appearing only long enough to throw out chips. (This is unlike chickadees, which
will carry their chips away from the nesting site, downies are not concerned
about predators finding chips at the base of the nesting tree.) Then the pair
will change shifts for 15 or 20 minutes while the other bird digs. Though the
female does most of the work, this may vary with individual pairs. Regardless,
the cavity is finished in about a week.
When the cavity is completed, sometime in mid~May, it is shaped much
like a gourd. The entrance is 1 !/4 inches in diameter. It is dug straight about
four inches, then curves down 8-10 more inches and widens to about three inches
in diameter. At the very bottom, the the cavity narrows to about two inches,
where a few chips are left to serve as a nest. It is believed that woodpeckers
have been nesting in cavities so long in evolutionary time that nesting material
is no longer used. Chickadees and bluebirds have been nesting in cavities for a
shorter period of time, and still build a nest at the bottom of the cavity as
they did when they built their nests in the open.
The eggs, too, reflect this. Species that have been using cavities for
many thousands of years, like the woodpeckers, lay pure white eggs. No
protective coloration is needed when they are hidden in a cavity. Bluebirds and
chickadees, on the other hand, still lay eggs with some protective coloration on
them~specks in the case of chickadees and pale blue in bluebirds' eggs.
Downy woodpeckers lay four to five pure white eggs, which are incubated
by both parents through the 12 days required for hatching. They take turns
during the daylight hours; the male incubates at night.
The downy, like other woodpeckers, will seldom use the same nesting
cavity year after year. Instead, the site is taken over the next year by
chickadees, titmice, tree swallows, wrens, and sometimes bluebirds. This forces
the downy couple to drill another nesting cavity each year.

Young Downies

When the young hatch, they are naked, blind, helpless, red-colored, and
quite unattractive. During the first few critical days after hatching, the
adults take turns in the cavity, one brooding the young while the other bird is
gathering food. The male usually broods at night.
Downies swallow and regurgitate their food to the young for only four
to five days. After that they carry insects and other bugs, primarily spiders,
ants, and moths, to the youngsters in their bills. The older the chicks get, the
more food the adults must provide. It isn't long before the young can be heard
chippering in the cavity and both parents are feeding from daylight until dark.
At times they are feeding as often as ounce a minute!
A few days after hatching, feathers start to grow on the young, and by
the time they are 14 days old, their tail feathers are long enough to support
their weight. It is then that they make their first appearance at the cavity
entrance. For the next week, the youngsters spend a great deal of their time
taking turns at the cavity entrance, heads out, chippering loudly, awaiting the
next meal. At 21 to 24 days, the young are ready to leave the cavity on their
first flight. A New York observer gave a good acount of a downy family's last
few days in the cavity: "The young chattered most of the time during the last
two days of nest life. One at a time they looked out a great deal at the
strange outer world. They left the nest on on the eleventh of June. The last two,
a male and a female, left during the afternoon, each after being fed at the
entrance and seeing the parent fly away. The young male flew from the nesting
hole straight to a tree 60 feet away. His sister quickly followed, lighting on
the trunk of the same tree and following her parent up the bole in the hitching
manner of their kind as though she had been practicing this vertical locomotion
all of her life."
The observer could distinguish male youngsters from female because they
already had a slightly different appearance. Like their adult counterparts, the
young males have red on their heads and the females do not. The red on the head
of the juvenile male is not a small spot on the back of the head as in the adult
male, but a much larger area of red and pink on the whole crown. The youngsters
are also somewhat fluffy or "downy" looking. The juvenile female looks like the
juvenile male, without the red crown.
This juvenile plumage will be worn but a short time, for all downies,
young and adult, molt into winter plumage in September.
Ounce the young have fledged, the parents divide the brood and only
take care of their charges. The male will usually take one or two of the young,
while the female takes the others. According to study, young downies become
independent at the age of 41 days. Many people have seen youngsters on suet
feeders in late summer with no apparent adult escort, nor any interest in other
downies in the area. In fact, the adults will drive off the youngsters at the
suet feeders.
Downy woodpeckers have only one brood a year in the north, but
sometimes two in the south.

Winter for a Downy

By September the downy woodpecker family has broken up, the young of
the year look like adults, and all become solitary and quiet.
As cold weather approaches, the first order of business is to locate a
winter roosting cavity. Apparently, downies do not use their nesting cavities as
winter roosts; most birds drill fresh roosts in anticipation of the long winter
ahead.
These preparations, however, are not made at the fast pace of most
other birds in autumn. The species that must migrate to warmer climates seem to
be restless and in such a hurry about everything. But not the downy. It remains
calm in the midst of the hustle. Such is the personality of the permanent
resident. Despite this, there are some studies which indicate that some downies,
particularily females, do leave the breeding territory; others don't. The
reasons for these variations are not clear.
The down's winter is spent quietly and alone, searching the doormant
woodland for food. The pace of life has slowed, and often its tap, tap, tap is
the only sound to be heard above the wind in the trees. The downy is well
equiped to survive the coldest weather. It even takes playful baths in the snow
piled high on branches. A woman in Canada described one such incident: "This
morning a female downy flew to a horizantal branch and proceeded vigorously to
bathe in the loose snow lying there. Like a robin in a puddle. Mrs. Downy ducked
her head, ruffled her feathers and fluttered her wings, throwing some of the
snow over her back and scattering the rest to the winds."
The downy woodpecker's winter food is not unlimited. The insects apon
which it survives stopped multiplying when cold weather arrived. As time passes,
the bird must search more and more diligently to feed itself. It gets some help
from the bands of chickadees, titmice, and nuthatches with whom it shares the
winter woods. Downies will often stay loosely associated with these species as
they cruise the woodlands in search of hidden morsels. But the downy is tied
somewhat to the area near its roosting hole, since it will return to it every
evening at sunset. Therefore, the feeding areas surrounding the roosting cavity
become a downy's individual winter feeding territory, which it will defend
against other downies.
Backyard feeding stations are the exception. For some unexplained
reason, feeding stations are a "common ground" for all birds in all seasons.
Usually (in the right conditions) there will be between six and ten downies at
suet feeders at various times every day during the winter. There will be fewer
during the summer. That is probably because there is more natural food in the
summer and breeding territories are more rigorously defended. Regardless, the
downies take turns at feeders, abiding by some kind of truce at the suet, though
there are often fights over who feeds first.

Territorial Disputes

When two males or two females come face to face over a territorial
dispute, they spread their wings, raise their crests and assume a challenging
attitude and scold each other. Most of this is bluff, of course, for they soon
settle down, unless one or the other advances toward a female.

Flight

Like the other members of the woodpecker clan, the downy has a
distinct undulatin flight that is most evident when it crosses open areas or
swoops through woodlands. The dips are not as deep as those of a goldflinch, but
as ornithologist Arthur Cleveland Bent said, "It gives the effect of a ship
pitching slightly in a heavy sea. A few strokes carry the bird up to the crest
of the wave~ the wings clapping close to the side of the body~ then, at the
crest, with the wings shut, the bird tilts slightly foward, and slides down into
the next trough."

Enemies & Camouflage

Though no songbird is totally safe from predators, not many downy
woodpeckers fall prey to hawks, owls, and other winged hunters. When attacked,
downies are quite adroit at dodging raptors by flitting around the branches of
their natural habitat. They can also flatten themselves against the bark of a
tree trunk and become almost invisible to any pursuer. Maurice Thompson
described a downy's defense against a goshawk: "The downy darted through the
foliage and flattened itself against a large oak bough, where it remained
motionless as the bark itself. The hawk lit on the same bough within a few feet
of its intended victim, and remained sitting there for a few moments, searching
in vain. The black and white feathers of the downy blended perfectly with the
bark and lichen on the tree."
Other enemies, strangely, include house wrens, which have been known
to wait until downies have completed work on their nesting cavaties before
appropriating the site for themselves. Unbelievable as it may sound, the house
wren can be aggressive enough to attack a pair of downies and drive them from
their own nesting site to procure the cavity for its own.
Squirrels, particularly red squirrels, will destroy the eggs and young
of downy woodpeckers.

Attracting Downies

Food, cover, and water are the three basic needs of all wildlife and
downy woodpeckers are no exception. Food and cover definitely take priority over
water, as downies seldom drink at birdbaths.
Mature trees in an open woodland are the preferred habitat, but any
kind of natural cover is better than none at all. A mixed stand of oaks,
basswood, maples, and willows will suit downies perfectly.
Food is simple. Downy woodpeckers love beef suet. Be sure that you get
real beef suet at the butcher shop. So often a butcher will give or sell you
beef fat, which downies will reluctantly eat in the winter. They prefer real
suet, which is the hard, white, opaque fat surrounding the beef kidney. Regular
beef fat has a greasier, translucent appearance. It will also decompose in warm
weather and attract flies. Suet will not. That is why beef suet is reccomended
all year long. It is every bit as successful with downies in summer as winter.
Plus, the suet feeder is the place where most of the baby downies are first seen
by humans. They are so cute with their red caps and roly-poly appearance. At
first a parent bird feeds the youngster suet. Then it tries to get the youngster
to feed itself. All that free entertainment is yours to enjoy if you put up a
suet feeder.
Other feeding station foods that downies will eat include peanut
butter (it's a fallacy that peanut butter sticks in the throats of birds),
doughnuts, nutmeats, sunflower seeds, corn bread, and cracked corn kernels. But
beef suet is by far the most popular with all the woodpeckers.
Will a downy woodpecker nest in a bird house? Though most books on
attracting birds or building birdhouses give dimensions for downy woodpecker
houses, there does not appear to be any record of a downy nesting in a man-made
house. However, there are records of downies using birdhouses as winter roosts.

Special Adaptations

The downy has many adaptations, ranging from the tail feathers to the
tongue.
First of all the downy's toes are different than most other birds.
Instead of having three toes in the front and one in the back, the downy has two
toes in the front and two in back. This arrangement makes the downy's unique
tripod of two feet and stiff tail feathers more effective. The toes have also
adapted another way. The outer hind toe is longer than the rest of the toes to
keep it from swaying.
The downy's tail is also special. Unlike most birds the downy's tail
feathers are long and stiff. This helps balance the birds weight as it stands
vertically on a tree.
Another adaptation of the downy woodpecker is their unusual bill. It
is not pointed like most other birds, but it is chisel-shaped. A chisel- shaped
bill makes the downy's work of carving a nesting and roosting cavity easier. The
bill also helps the downy chip the wood around the insects buried in a tree. The
tongue is also worth noting. At twice the size of the downy's head, the tongue
easily spears small morsels with a horny tip of recurved barbs.
Yes, even the skull has changed to fit the downy's needs. The skull of
the downy is stronger and thicker than most other birds. So logically it is also
heavier. This extra weight makes the little jackhammer more effective.
But most amazing is not how the downy has adapted, it is its skill to
adapt. When European settlers invaded the downy woodpeckers' territory 200 to
300 years ago, the birds did not retreat as did many of our native species.
Instead, they accepted as a home the orchards and shade trees with which man
replaced the forests. Our early ornithologists were in agreement when they
characterized the bird. Audubon remarked in 1842 that it "is perhaps not
surpassed by any of its tribe in hardiness, industry, or vivacity."
Alexander Wilson said ten years earlier that "the principal
characteristics of this little bird are diligence, familiarity, perseverance,"
and spoke of a pair of downies working at their nest "with the most
indefatigable diligence."
And so it is today. The downy woodpecker remains unspoiled and
unconcerned by the threats of man. It just quietly flits around the backyard
woodland, tap, tap, tap-ing its way through life.