Meadow mice inhabit practically the whole of the Northern Hemisphere--
America, north of the Tropics; all of Europe, except Ireland; and
Asia, except the southern part. In North America there are few wide
areas except arid deserts free from meadow mice, and in most of the
United States they have at times been numerous and harmful. The animals
are very prolific, breeding several times a season and producing
litters of from 6 to 10. Under favoring circumstances, not well
understood, they sometimes produce abnormally and become a menace to
all growing crops. Plagues of meadow mice have often been mentioned
in the history of the Old World, and even within the United States
many instances are recorded of their extraordinary abundance with
accompanying destruction of vegetation.
The runs of meadow mice are mainly on the surface of the ground under
grass, leaves, weeds, brush, boards, snow, or other sheltering litter.
They are hollowed out by the animals' claws, and worn hard and smooth
by being frequently traversed. They are extensive, much branched, and
may readily be found by parting the grass or removing the litter. The
runs lead to shallow burrows where large nests of dead grass furnish
winter retreats for the mice. Summer nests are large balls of the same
material hidden in the grass and often elevated on small hummocks in
the meadows and marshes where the animals abound. The young are brought
forth in either underground or surface nests.
Meadow mice are injurious to most crops. They destroy grass in
meadows and pastures; cut down grain, clover, and alfalfa; eat grain
left standing in shocks; injure seeds, bulbs, flowers, and garden
vegetables; and are especially harmful to trees and shrubbery. The
extent of their depredations is usually in proportion to their numbers.
Thus, in the lower Humboldt Valley, Nevada, during two winters (1906-8)
these mice were abnormally abundant, and totally ruined the alfalfa,
destroying both stems and roots on about 18,000 acres and entailing a
loss estimated at fully $250,000.
When present even in ordinary numbers meadow mice cause serious
injury to orchards and nurseries. Their attacks on trees are often
made in winter under cover of snow, but they may occur at any season
under shelter of growing vegetation or dry litter. The animals have
been known almost totally to destroy large nurseries of young apple
trees. It was stated that during the winter of 1901-2 nurserymen near
Rochester, N. Y., sustained losses from these mice amounting to fully
$100,000.
Older orchard trees sometimes are killed by meadow mice. In Kansas in
1903 the writer saw hundreds of apple trees, 8 to 10 years planted, and
4 to 6 inches in diameter, completely girdled by these pests. (Fig.
2.) The list of cultivated trees and shrubs injured by these animals
includes nearly all those grown by the horticulturist. The Biological
Survey has received complaints of the destruction of apple, pear,
peach, plum, quince, cherry, and crab-apple trees, of blackberry,
raspberry, rose, currant, and barberry bushes, and of grape vines; also
of the injury of sugar maple, black locust, Osage orange, sassafras,
pine, alder, white ash, mountain ash, oak, cottonwood, willow, wild
cherry, and other forest trees.
[Illustration: FIG. 2.--Apple tree killed by meadow mice.]
In the Arnold Arboretum, near Boston, Mass., during the winter of
1903-4, meadow mice destroyed thousands of trees and shrubs, including
apple, juniper, blueberry, sumac, maple, barberry, buckthorn, dwarf
cherry, snowball, bush honeysuckle, dogwood, beech, and larch. Plants
in nursery beds and acorns and cuttings in boxes were especial objects
of attack.
The injury to trees and shrubs consists in the destruction of the bark
just at the surface of the ground and in some instances for several
inches above or below. When the girdling is complete and the cambium
entirely eaten through, the action of sun and wind soon completes the
destruction of the tree. If the injury is not too extensive prompt
covering of the wounds will usually save the tree. In any case of
girdling heaping up fresh soil about the trunk so as to cover the
wounds and prevent evaporation is recommended as the simplest remedy.
To save large and valuable trees bridge grafting may be employed.