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Bison in its natural environment Print

In the yearly life cycle of the bison in the Bia這wie瘸 Forest, there are two different periods: The first period – is the time of the winter concentration, lasting for the whole winter period. The second one – is the period of free roaming during the season when there is no snow cover, coinciding to a large extent with the plant vegetation period in the forest. Then bison take advantage of the natural food resources and follow their specific way of utilizing their natural environment.

During winter time, bison gather around the location of animal feeders, creating large winter groups with several dozen specimens.  Some bulls create at this time separate, smaller groups in other feeder locations or roam freely across the Forest. At the turn of winter and spring, winter groups become unstable and start breaking up into smaller groups, which start leaving the feeder location and start roaming across the Forest looking for natural food.

Basic social groups in the population include mixed groups and bull groups. Mixed groups comprise cows, 2-3 years old youngsters, calves and periodically adult bulls. In the Polish free roaming population, the average size of a mixed group is currently equal to 13 specimens, at maximum reaching the size of 92 specimens.  The grand majority (more than 80%) of the mixed groups has up to 20 bison, large groups are very infrequent to come by. Only in the Belarusian bison population, on cultivated meadows, it is possible to come across large mixed groups with 40 -140 specimens. The average size of a bull group is equal to 2 specimens, though it is most common to find small bull groups of 2-3 specimens – large groups with 4-9 specimens are hard to come across.  Approximately 60% of bulls live alone.

Bison groups do not coincide with any family ties and their contents as well as size change frequently.  Some of the changes are seasonal (birth of calves, arrival of bulls during the breeding period), other changes result from bonding of several groups and then their separation, where new bonds are created.  A mixed group is typically headed by an older cow with a calf.

This view stays in the memory for a longer time. Photograph by J. Walencik


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