Assessing the size of the bear population is largely based on observations of litters of cubs younger than one year of age, reported by the network of large carnivore contact persons. Compared to other bears, bears with a litter travel in an area that is limited in size and their territories overlap less than those of other bears occupying the same area.
Various methods are used to assess the number of individual litters, including distance criteria, the dates of observations, information on the number of cubs, and the size of the paw prints of females and cubs. Distance criteria are based on data obtained from the travel patterns and the size of the territory of females fitted with GPS senders and accompanied by litters of cubs. The total number of bears is assessed by multiplying the number of litters by ten.
In observations in Western and Southern Finland, bears travelling alone tend to be the norm. In these areas, litters are rare and the bear population is principally made up of young males.
Genetic methods are becoming increasingly common
Genetic methods will form part of the monitoring of the bear population in the near future. The basic material for this comprises excrement samples, from which DNA can be extracted to form a basis for assessing the number of individuals and which provide sufficiently comprehensive information.
The relationship between individual bears and the number of samples indicates the number of samples required to establish the number of bears. As the number of samples increases, the number of new individuals detected falls. Because it is expensive, this analysis method needs to be discontinued at the point where a very large number of samples need to be analysed to identify an individual bear.
Due to their high cost and the time taken to complete them, genetic methods will not replace observations, but they do provide a baseline against which observational data can be checked.
Photo on top of the page: Petri Timonen