Monitoring of bears

2) Monitoring of bears

The bear is a shy animal that moves over extensive areas. To monitor them we equip them with radio transmitters or GPS-receivers. Until 2003 we used only the traditional VHF technology (i.e. radio transmitters). Since then we have replaced more and more of those with GPS-collars.

The bears that still have regular radio transmitters are currently located one to two times per month during the non-denning season. This low level of monitoring is sufficient to continue the long-term demographic study of the population. It gives us a rough idea of their use of area, documentation of their dispersal, and we can also locate a bear and determine the reason for its death. Mainly female bears are included in this study and we mark their yearlings in the spring, before they have separated from their mother. Thus we can keep track of bears and their kinship through generations. We study the survival of cubs and the time of separation by tracking the radio-marked females with a helicopter to observe them and count their cubs. We count cubs three times per year; 1) in spring after they have left the den, 2) in summer following the mating season, and 3) in fall before they enter the den.

The bears with GPS-collars give us a whole different flow of data, compared to those with radio transmitters. As a standard we have programmed the GPS-receiver to take a position every 30 minutes during spring, summer and fall, and one position per day during winter, while the bears are in the den. The GPS-positioning schedule can be reprogrammed for a more or less frequent positioning, depending on which study the bear is included in. Very frequent and exact positioning enables us to more precisely and on smaller scales than before study aspects of bears’ biology, such as their movements through the landscape, behavior, predation and  habitat selection. By having many bears equipped with GPS-collars simultaneously in the same area, we can also study the interactions among bears and how they are effected by gender, kinship, and season.