Ellsworth American. [volume] (Ellsworth, Me.) 1855-current, 1911-11-01

ana WOOD FrO00ct9s
TBy w. L. McAtee, Assistant Biologist, Bio
logical Survey, U. s. Department Of Agricul-
ture.l
Woodpeckers are peculiarly dependent
upon trees, which furnish them food,
shelter and cradles for their young. No
birds are more highly specialized nor more
perfectly adapted to particular mode OF
life than are most woodpeckers to arboreal
existence. Moreover, as trees are impor-
tant to woodpeckers, so ere these birds
important TO trees.
Woodpeckers benefit trees by consum-
ing many Of the most destructive forest
pests, insects largely inaccessible to other
birds. In securing these insects, however,
which constitute the bulk OF their food,
and in making nestsl and shelter cavities,
woodpeckers have another significant
economic relation to trees, for they re-
move bark and wood from both dead and
living trees. In the case OF dead trees lit :.
tie or no harm is done. When, however,
they make excavations in living trees, the
birds destroy more:or less OF the cambium
layer, from which proceeds the.growth Of
both wood and bark Slight injuries to
the cambiura result in distorted growth,
but the destruction Of large areas may
cause death. Since trees are exceedingly
valuable to man, the habits Of birds whose
relations are SO vital are OF much economic
Importance.
1t is the purpose this bulletin to ex-
anime the evidence for and against wood
peckers and to determine their status ac-
cording to the effect ofitheir habits upon
trees and wood products. Injuries by
woodpeckers are treated under two heads:
~ damage by woodpeckers in general;
l2) injuries due almost exclusively 10 the
three species property known - sapsuck-
ers.
This topic may ba.divided into two sec
tions: Damage to trees and damage to
wooden posts and structures. Primarily
the work of woodpeckers on the living
parts OF trees is injurious. The important
cambium layer is injured every time nest
is excavated or an insect dug out. To
what extent the various injuries are Offset
by beneficial activities OF the birds will be
discussed later.
As rule the holes made by woodpeck-
ers when digging out insectsare not large,
and there is every reason to believe that
most Of them heal quickly without no.
ticeably distiguring the exterior OF the
trees. They cause distortion and staining
Of the wood, however, as do all injuries to
the cambium. These defects often resem-
BILE those which result from sapsucker
work, but they generally occur in other
wise unsound trees and are much less
numerous and important. However,
wounds made by woodpeckers when dig
ging out borers deeply buried in the wood,
by reason OF their larger size, often result
In bleaching the wood, q feature rarely
observed in connection with the smaller
sapsucker pecks.
Our two largest species OF woodpeckers,
the pileated and the ivory billed, dig
great pits or burrows in living trees or
split on large chips. r. NJ. Chapman
says: II have seen an opening made By Z
pileated woodpecker In . white pine tree
twelve inches long, four inches wide, and
eight inches deep. through perfectly
sound wood, to reach the larvB at work in
the heart OF the tree" These large wood
peckeS occasionally riddle trees which
snow no signs OF insect attack, but this il
20 unusual % not to warrant hostility to-
waro THESE nne birds, which are disap-
pearing only too rapidly q man en-
croaches upon their domain.
All woodpeckers chip OF considerable
wood from dead trees and branches to
secure the insects therein. In spite Of the
good done BY destroying these insects,
IN some countries woodpeckers are held in
disrepute because they reduce the guam
tity OF nrswood-a view not likely to Be-
adopted in the United States.
Indeed the ofioes OF woodpeckers in
capturing the vnriouslwood. boring insecta