THE BIRDS
MODOC WOODPECKER. Dryobates villosusorius Oberholser
Field characters.A
woodpecker of size of Robin or slightly less. Upper surface black, with
a broad white stripe down middle of back; whole under surface, including
outer tail feathers, uniformly white; small spots on wing, stripe below
eye, and another stripe behind eye, white. (See pl. 5f). Adult
males have narrow fringe of red feathers across back of head, but this
is not often to be seen at a distance. Voice: A single sharp
note, speenk, uttered at irregular intervals.
Occurrence.Resident in
moderate numbers throughout the region except in the Lower Sonoran Zone
and above timber line. Observed at Pleasant Valley and thence eastward
to vicinity of Mono Lake; highest station of record, Warren Fork of
Leevining Creek at 9300 feet altitude. Forages in more open stands of
both coniferous and deciduous trees.
The Modoc Woodpecker is but a local race of the
wide-ranging 'hairy' woodpecker, which is found practically everywhere
in the forested regions of North America. As with most of the allied
forms, the present race ranges through several life zones, from the
scattered digger pines at Pleasant Valley eastward through the main
forest belt to the sparse tracts of Jeffrey pines in the vicinity of
Mono Lake. It is nowhere really common, even for a woodpecker; it
reaches its greatest numbers in the upper part of the Transition Zone
and in the Canadian Zone.
The Modoc Woodpecker is identical in pattern of
coloration with the much smaller Willow Woodpecker, save that the outer
tail feathers of the larger bird are pure white, whereas in the smaller
species they are barred with black. The special plumage features which
are associated with differences in sex and age are likewise identical in
the two species. Adult males have a narrow fringe of red feathers across
the back of the head (pl. 5f), whereas young males have the whole
top of the head red. Adult females entirely lack the red color and young
females have only a few scattered red feathers on the crown.
A comparison of the weights of these two woodpeckers
shows that the Modoc is about two or three times as heavy as the Willow
Woodpecker. Thus, male Modoc Woodpeckers weigh on the average 68.1 grams
(2.4 ounces) and females 58.9 (2.1 ounces), whereas Willow Woodpeckers
weigh 27.0 (0.95) and 24.4 grams (0.86 ounces) respectively. The Nuttall
Woodpecker, a Sonoran Zone species of similar build and proportions to
the two species just mentioned, weighs 41.2 (1.45) and 34.4 grams (1.2
ounces), for the two sexes, respectively, being thus fairly
intermediate.
During the summer months we rarely saw in a morning's
walk more than one individual of the Modoc Woodpecker. But in Yosemite
Valley, during the winter season, the birds seemed as noisy and
conspicuous as they had been quiet and unobtruding before. Perhaps this
impression was enhanced by the absence of the voices of summer birds.
One of our notebook records (December 20, 1914) reads:
Four seen in two and a half hours; the most
noticeable bird, making enough noise to give the impression of many. No
"rolling," but much tapping and frequent high-pitched "speenks"; birds
working on dead limbs of tall cottonwoods and black oaks on the Valley
floor.
The Modoc Woodpecker forages on both evergreen and
deciduous trees, favoring the latter, perhaps, during the winter months.
In summer it is usually rather quiet, particularly so as compared with
the noisy California Woodpecker. It gains much of its food in the outer
portions of the bark, where a few strokes of moderate intensity enable
it to secure any insect or grub living near the surface of the tree.
At the margin of the forest above Coulterville, May
31, 1915, a Modoc Woodpecker was seen foraging in a yellow pine. The
tree in question had recently been killed by the boring beetles which
were common in the western forests that year. The woodpecker was going
over the tree in systematic manner, working out and in along one branch,
then ascending the trunk to the next branch where it would repeat the
performance. The bird was flaking off the outer layers of the bark
without much evident expenditure of effort, for little noise of tapping
was heard; it was feeding presumably on the boring beetles or their
larvae.
At Gentrys on October 23, 1915, a Modoc Woodpecker
was seen enlarging a hole in a pine tree, perhaps preparing a shelter
for use during the winter months. The bird worked actively, but paused
frequently as if to inspect its work.
At Chinquapin, on May 19, 1919, a pair of these
woodpeckers was seen going through their courting antics. A male was in
a large yellow pine at the edge of a logged-over area, calling almost
incessantly. His usual speenk had become
spenk-ter-ter-ter, a staccato run repeated every few seconds. The
female answered in like voice but uttered the trill less often. The male
changed his location many times, and after protracted calling on his
part, the female flew to the same tree.
On June 24, 1920, in Yosemite Valley, a brood of
full-grown young in a row of large cottonwoods near the Ahwahnee
footbridge was much in evidence by reason of their calls and active
behavior.
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