Wolf Captures & Radio Collaring

Wolf monitoring and research in Yellowstone depend on our ability to obtain population data and information about the wolves' movements. The most effective way to obtain accurate information is to equip some of the wolves with radio collars that can be tracked during aerial and ground surveys. To be able to track each wolf pack, at least one wolf in the pack must be collared. However, because wolves wearing the collars may disperse from their pack or die, and the collars may malfunction or be chewed off, staff try to keep more than one wolf in each pack collared so that there is a backup collar in the pack. Each year, 25–30 wolves are captured by darting them with a tranquilizer from a heli­cop­ter so that they can be collared. Whenever a wolf is captured, staff take the opportunity to measure and weigh the wolf, and obtain a blood sample for genetic and disease analysis. At the end of 2007, 57 (33%) of the 171 wolves that reside primarily in Yellow­stone National Park were collared.