To mark and collar bears, we must capture and immobilize them. Bears are captured from a helicopter by an experienced team using a remote drug delivery system (Dan-Inject). Most captures are made in spring, shortly after bears have emerged from their dens. Spring provides the best conditions, when remaining snow cover and minimal vegetation make it easier to find the bear, open water in the terrain is limited, and ambient temperature is relatively low. While the bear is immobilized, we either put on, take off, or replace its technical equipment. We record a number of health status parameters and take samples for genetic and other studies. From bears of unknown age, we pull a tooth (a premolar without function for the bear) for age determination. Additionally we weigh the bear and take a number of body measurements. When a bear is captured for the first time, we give it a coded ID number, attach an eartag, inject a microchip into the skin and tattoo its ID number inside the lip. Together with the DNA information, this ID-marking is important to ensure a secure identification of the bear next time it is encountered.
The document “Biomedical Protocols for Free-ranging Brown Bears, Gray Wolves, Wolverines and Lynx, 2007″ describes the procedures of capture, immobilization and radio-marking in detail.
a) Immobilization Update 2008
Since the project started in 1984, bears have been captured yearly. Until and including 2008, a total of 1431 captures have been made of 603 individual bears. Of these 405, have been radio-tagged. The number of captures exceeds the number of individuals because many bears have been captured several times. A radio-tagged bear is generally captured at two-three year intervals to replace its transmitter/receiver. Each year we loose contact with some of our marked bears. Most of them have been shot during the bear hunt, others are lost to us because their collar has fallen off. Also, it is not uncommon that younger bears are killed by older, more dominant bears. Most of the knowledge about bears that the project has acquired is based on the data from the 1414 bear-years that we have monitored individual bears. (One bear-year means that an individual has been monitored for a full year, or that 2 bears have been monitored for half a year each, etc). During 2008, a total of 91 bears were followed until they entered their dens.