The Manitowoc pilot. [volume] (Manitowoc, Wis.) 1859-1932, 1909-07-08
MIGRATION OF RATS.
Marches of Rodents That Have Been
Observed in Various Countries.

In nearly all countries seasonal move
ment of rats from houses and barns to
the open fields occurs in spring, and the
return movement takes place rs cold
weather approaches. The movement is
noticeable even in large cities.
More general movements of rats often
occur. In 1903 multitude of mgrat-
ing rats spread over several counties of
western Illinois They We're noticed es-
pecially in Mercer and Rock Island coun-
ties. For several years prior to this in
vasion no abnormal numbers were seen,
and their coming was remarkably sud
den. An eyewitness to the phenomenon
Informed the writer that as he was re-
turning to his home by moonlight he
heard general rustling in the field near
by, and soon vast army of rats crossed
the road in front of him, all going in one
direction. The mass streached away as
far as could be seen in the dim light.
These animals remained on the farms
and in the villages of the surrounding
country, and during the winter and sum-
mer of 1904 were a veritable plague. a
local newspaper stated that between
March 20 and April 20. 1904, +. u.
Montgomery of Presumption, Mercer
county, killed 3435 rats on his farm. He
caught most of them in traps.
In 1877 a similar migration occurred
into parts of Saline and Lafayette coun-
ties, Mo. and in 1904 another came UNI
der the writer's observation in Kansas
river valley. This valley for the most
part was flooded by the great freshet
of June, 1903, and for about ten days
was covered with several feet of water.
1t is certain that most of the rats in the
valley persisted in this food, In the fall
of 1908 much of the district was visited
by hordes of rats, which remained dur
ing the winter, and by the following
spring had so increased in numbers that
serious losses of grain and poultry re-
suited.
No doubt the majority of the so-called
migrations of rodents are in reality In
stances of unusual reproduction or of en-
forced migration owing to lack of food.
In England a general movement of rats
inland from the coast occurs every DC
tober. This is closely connected with
the closing of the herring season. Dur
ing the fishing the rodents swarm to the
coast. attracted by the offal left from
cleaning the herring, and when this food
supply fails they hasten back to the
farms and villages.
In South America periodic plaques OF
rats have taken place in Parana. Brazil,
at intervals of about thirty years, and in
Chile at intervals of from ntteen to
twenty-five years. These plaques in the
cultivated lands follow the ripening and
decay of the dominent species of bamboo
in each country. The ripening of the
seed furnishes for two or more years
favorte food for the rats in the forests.
where the animals multiply greatly;
when this food fails they are forced to
the cultivated districts for subsistence.
In 1873 almost the entire crops of corn,
rice and mandioca in the state of Pa
rama were destroyed by rats, causing
serious famine.
An invasion of black rats in the Ber-
muda islands occurred about the year
1915. In space of two years they had
! L. oil AI,% nx,f N
island was free from them. The rodents
devoured everything which came in their
way-fruit, plants, and even trees-,so
that for two years the people were des-
titute of bread. A law was passed re-
quiring every man in the islands to set
twelve traps. In spite of all efforts the
animals increased, until they finally dis
appeared with suddenness which could
have resulted only from pestience.-
Biological Survey Bulletin SO.