the field-mice of the type Microtus includes approximately 50 types. they are economic for the human being of biggest importance. Sundries types of these voles are inclined to intermittently recurrent mass-increases, what can cause the feared mouse-nuisances and arises for the agriculture million-damages. The ecologist calls such population-fluctuations mass-changes.
Field-mice become particularly in grains, clover, and turnip-fields damaging. In field-barns, they attack the stored field-fruits. Beside the economically most important type, the field-mouse (Microtus arvalis), some further important European types should be mentioned shortly.
Field-mouse (Microtus arvalis)) it is the most frequent mammal in Central Europe. it parts herself from the very similar Erdmaus through the somewhat lighter, brown - until yellow-gray color and the bigger eyes distinguishes. The length amounts to 9-12 cm, the short tail becomes approximately 4 cm long.
Way of life The field-mouse populates particularly fields and meadows, is also at the beach, however, to be found in moorland-ships and open jaw-forests. it is colony-wisely alive. its shallowly lying walk-systems contain a nest-chamber, storerooms and escape-tubes. The exits are above ground interconnected through solid changes. These run-walks become übertunnelt under the snow-blanket with woven grass and earth in the winter so that they can still be used. After the melting away the snow, one gets an impressive picture of the wintry activity of these mice. In the run-walks, special excrement-places are up set. Even if the field-mouse disappears from the construction to the food-search further, it usually uses the same ways. they off itself up to half a kilometer of the nest, with what durchschwimmt it also waters.
The field-mouse is meets - and night-active. Silence and activity-periods constantly alternate in several-hour rhythm.
Reproduction The field-mouse multiplies extraordinarily quickly. 3-12 become after approximately 20 days, usually 5 kids born. The newborn females are combination-ready already after 13 days. In the year, up to seven throws are possible. One single mouse-pair can have over 2000 descendants theoretically in the year!
Nutrition The field-mouse can become very damaging. it eats field-fruits like grains, clover and turnips, grass and bark. With favorable food-conditions, mass-increases often occur. It can then occur with high population-densities that is destroyed until half the grain-profit. After such mouse-nuisances, however, food-lack and to high Individuendichte causes breakdowns of the populations again and again.
The field-mouse serves a series of enemies in turn as food. Above all by gripping-birds, owls, foxes and mouse-weasels, it is carried off.
Erdmaus (Microtus agrestis)) With a head-torso-length of 9,5-12,5 cm, it is somewhat bigger than the field-mouse. its fur is more brown, the hair longer. The Erdmaus prefers moister habitats than the field-mouse, whom it resembles in life-rhythm and reproduction however largely. The Erdmaus usually builds its nest over the earth out of plant-material. The food consists mainly of grass and herbs, with food-lack also out of bark. it can therefore become very damaging in afforestations.
Snow-mouse (Microtus nivalis)) it is the lightest of our native voles: The fur-color is enough from light - until silver-gray. With a head-torso-length of 12-14 cm, it is bigger than field and Erdmaus. The snow-mouse is a high mountain region-inhabitant, it preferentially sunny, rocky places. The nest usually is in crevices. The food of the snow-mouse consists of grass, Alps-herbs and seeds. it can climb well and can jump. A throw consists of 2-7 boys. The snow-mouse is regarded endangered as potential with us.
Swamp-mouse (Microtus oeconomus)) it resembles the Erdmaus very much, possesses a shorter fur and a longer tail, however. The head-torso-length amounts to 10-12 cm. Occurs there is still in the Mark Brandenburg while it probably occurs no more in the western federal states. To east, its spread stretches as far as after China. it prefers very moist areas, Z. B. Shores, swamps and alder-breaks. The nest is placed against dry places in the reed or on Seggenhügeln. The swamp-mouse digs less than the other field-mice. As food, it loves particularly the outer skin of Binsenstengeln. The female tosses 4-9 kids.
The swamp-mouse is on the red list of the types threatened by the extinction with us.
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