The northern birch mouse (''Sicista betulina'') is a small
rodent
Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...
about long (without the tail), weighing . It lives in northern Europe and Asia in forest and marsh zones.
It
hibernates in
burrow
file:Chipmunk-burrow (exits).jpg, An eastern chipmunk at the entrance of its burrow
A burrow is a hole or tunnel excavated into the ground by an animal to construct a space suitable for habitation or temporary refuge, or as a byproduct of Animal lo ...
s. It eats shoots,
grain
A grain is a small, hard, dry fruit (caryopsis) – with or without an attached husk, hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and ...
s, berries, and sometimes
insect
Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...
s.
Description
The northern birch mouse is a small mouse with a relatively long tail. The adult head and body length is with a tail of . Adults vary in weight between . The upper parts are yellowish-grey with a brown sheen and the underparts are a pale greyish-yellow. A black stripe runs along the spine from the head to the base of the tail. Its voice is a high-pitched whistle.
Distribution and habitat
The northern birch mouse occurs in Scandinavia, Central and Eastern Europe, and Northern Asia. Its main range extends from the Baltic region, Poland and the Czech Republic eastwards as far as
Lake Baikal
Lake Baikal is a rift lake and the deepest lake in the world. It is situated in southern Siberia, Russia between the Federal subjects of Russia, federal subjects of Irkutsk Oblast, Irkutsk Oblasts of Russia, Oblast to the northwest and the Repu ...
in Siberia, and from the Arctic Circle southwards to the
Carpathians
The Carpathian Mountains or Carpathians () are a range of mountains forming an arc across Central Europe and Southeast Europe. Roughly long, it is the third-longest European mountain range after the Urals at and the Scandinavian Mountains ...
. Isolated populations occur in Norway, Sweden, Denmark, Germany, and Austria.
[ Its natural habitat is coniferous forests, mixed deciduous woodland, marshy woodland, and damp bushy grassland, and it is sometimes found in cereal crops.][
]
Biology
The northern birch mouse is largely herbivorous
A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat n ...
and feeds on buds, shoots, grass seeds, and berries, but it also takes earthworms, insects, and snails, often finding these under loose bark. It is a skillful climber and often clambers around in trees and shrubs, gripping the twigs and branches with its five-toed feet and using its prehensile tail for additional support.[ This mouse hibernates in winter, seeking out a natural crack or the burrow of another animal, in a dry location such as on an embankment or in a bushy place. Other sites chosen can be in a hollow tree, in a tree stump or fallen log, or in a gap under a rock.][ During the hibernation period, which may last from October to May, the tail is wrapped spirally around the animal's body.][
]
Status
The northern birch mouse has a very large range. In Western Europe, it is generally uncommon with isolated subpopulations, but further east it is very common. Its population trend is unknown, but the IUCN
The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...
lists the species as being of least Concern
A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...
, as it considers that it is unlikely to be declining at such a rate as to justify including it in a more vulnerable category. No specific threats to this mouse have been identified, but agriculture may affect its numbers in Germany, and deforestation may affect it in Romania.[
]
See also
* Forest dormouse
* Balkan mole-rat
References
{{Authority control
Mammals described in 1779
Taxa named by Peter Simon Pallas
Sicista