Field mouse
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Field mouse ( Microtus arvalis ) |
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| Microtus arvalis | ||||||||||||
| ( Pallas , 1778) |
The field mouse ( Microtus arvalis ) is a mammal from the subfamily of voles (Arvicolinae). As a typical r-strategist, it is one of the most common mammals in Central Europe and shows cyclical mass reproductions.
features
The head-trunk length is 90–120 mm, the tail length 25–38 mm, the length of the hind foot 14.5–16 mm, rarely up to 17 mm and the ear length 9–12 mm. The animals usually weigh 18–40 g, rarely up to 51 g. The fur is yellowish gray on top, more brown in the west of the distribution area, more gray in the east. The underside is whitish and occasionally tinged with rusty yellow.
distribution and habitat
The distribution area of the field mouse covers large parts of the western, central Palearctic . It extends in a west-east direction from western Spain and western Brittany to western Mongolia . In a north-south direction, the area extends from northern Denmark and the extreme south-east of Finland to central Spain, in north Italy , south Bulgaria and north-east Turkey . There are isolated occurrences in the British Orkney Islands as well as in northern central Mongolia and the adjacent Siberia .
The field mouse mainly inhabits the open, agriculturally used cultural landscape, i.e. fields, short-grass meadows and pastures, but also, for example, dunes and dry and very open pine forests.
Systematics
In addition to the nominate form , the subspecies M. a. obscurus recognized, which can only be differentiated karyologically from the nominate form and was also considered by some authors as a separate species. The distribution of the two subspecies is parapatric . The eastern limit of distribution of M. a. arvalis runs northeast from the Dniester River in Ukraine and Moldova ; the area of M. a. obscurus adjoins that of the nominate form to the east.
The Orkney field mouse ( Microtus arvalis orcadensis ) is genetically similar to the continental mouse ( Microtus arvalis ). Their remains have been found in deposits of Skara Brae , proving their presence on Orkney for at least 4,000 years. It differs from Microtus arvalis by its smaller size, the shorter round ears and the shorter tail, which could be due to island dwarfing .
Way of life
The field mouse eats grass, herbs, seeds and grain. The animals live in moderately dense to very dense colonies in complex earth structures. The entrances to the buildings are connected to one another via a branching system of above-ground walkways, some of which are many meters long. In deep snow, these walkways are lined with earth at the top. The droppings are located in the walkways. Field mice are diurnal and nocturnal. An activity phase lasts three to four hours, followed by an equally long rest phase.
Reproduction and settlement density
The nest chambers are usually about 50 cm deep. The field mouse is a pronounced r-strategist and the population fluctuates very strongly. The species shows numerous adaptations to rapid reproduction under good conditions (high food supply and favorable weather), including very large litters with up to 13 young, a fast litter sequence, extremely early sexual maturity, continuation of reproduction even in winter and education of nest communities through several females of a litter, in which the females also suckle foreign offspring.
The gestation period is on average 21 days, the newly born young mice weigh on average 1.4 g. The eyes open at 11 days of age; the suckling period is 17 to 19 days. Females are sexually mature as early as 12-14 days, that is, during the suckling period, and are then mated frequently. A female can therefore give birth to the first litter at the age of 33 days. Mating immediately after the young are born is frequent, so the females can litter every 20 days under optimal conditions.
The local population fluctuates very strongly as a result of the cyclical mass increases. Gradations with maximum density occur in Central Europe usually every three years, in such years more than 1000 individuals per hectare can live. These maximum populations usually collapse suddenly and very quickly due to hunger and exhaustion. Normally, a gradation year is therefore followed by a so-called latency year with a very low population density. The stock fluctuations are particularly pronounced in spacious, open, monotonous agricultural landscapes without any noteworthy tree or shrub growth; in more diverse structured landscapes, the fluctuations are considerably lower.
Natural enemies
Because of their high frequency, at least in gradation years, the field mouse is a main prey for numerous birds of prey , owls and predatory mammals . In Central Europe, the kestrel , the long-eared owl and the mouse weasel are particular field mouse hunters.
Stock reduction in horticulture and agriculture
The field mouse is one of the most important pests in agriculture and horticulture. Field mice appear particularly in regions with better, deeper arable soils with good food supply and good cover, in areas with annual rainfall of up to 550 mm (Central German arid areas), on areas tilled without plowing, on areas planted with winter rape or winter grain as well as perennial forage crops, in clover and grass seed reproductive stocks often in quantities threatening the harvest. The control is carried out annually mechanically by plowing (destruction of the tunnels and nesting chambers), with low mouse infestation by setting up sitting crutches for mice-hunting birds of prey. In the event of a high infestation, the fight is carried out with a "laying gun" containing zinc phosphide poison baits in the field mouse outlets . Alternatively, these can be placed in special cardboard tubes that are only accessible to mice.
Existence and endangerment
As one of the most common mammals in Central Europe and Germany, the field mouse is not endangered; the world population is also safe according to the IUCN .
swell
literature
- Christine CK Boyce, Jesse L. Boyce III: Population biology of Microtus arvalis. I. Lifetime reproductive success of solitary and grouped breeding females. In: Journal of Animal Ecology. Vol. 57, No. 3, 1988, ISSN 0021-8790 , pp. 711-722.
- Fritz Frank: The Causality of Microtine Cycles in Germany (Second Preliminary Research Report). In: The Journal of Wildlife Management. Vol. 21, Issue 2, 1957, ISSN 0022-541X , pp. 113-121.
- Anthony J. Mitchell-Jones, Giovanni Amori, Wieslaw Bogdanowicz, Boris Krystufek, PJH Reijnders, Friederike Spitzenberger, Michael Stubbe, Johan BM Thissen, Vladimiŕ Vohralik, Jan Zima: The Atlas of European Mammals. Poyser, London, 1999, ISBN 0-85661-130-1 , pp. 228-229.
- Erwin Stresemann (founder), Konrad Senglaub (ed.): Excursion fauna of Germany. Volume 3: Vertebrates. 12th, heavily edited edition. G. Fischer, Jena et al. 1995, ISBN 3-334-60951-0 , p. 425.
Individual evidence
- ^ The field mouse on the IUCN Red List, distribution map
- ↑ z. BAJ Mitchell-Jones, G. Amori, W. Bogdanowicz, B. Krystufek, PJH Reijnders, F. Spitzenberger, M. Stubbe, JBM Thissen, V. Vohralik, J. Zima: The Atlas of European Mammals. Poyser, London, 1999: p. 228
- ^ Charles Tait: The Orkney guide book - Fauna p. 58
- ↑ Communication from the Thuringian State Office for Agriculture from July 2012 (PDF; 104 kB) ( Memento from December 19, 2013 in the Internet Archive ).
- ↑ Press release of the German farmers' association of July 12, 2012, field mouse plague in Thuringia and Saxony-Anhalt
- ↑ Eugen Winkelheide, Agricultural weekly paper Westphalia-Lippe 08/2014, page 32, 33
- ↑ Communication from the Thuringian State Office for Agriculture from July 2012 (PDF; 104 kB) ( Memento from December 19, 2013 in the Internet Archive ).
Web links
- Microtus arvalis in the endangered Red List species the IUCN 2006. Posted by: Amori, G., Hutterer, R., Krystufek, B., Yigit, N., Mitsain, G. & Muñoz, LJP, 2008. Retrieved on third November 2009.
- spurenjagd.de : Field mouse - collection of trace data