Oregon's black bear hunters must now check-in all black bears killed by state wildlife managers, who will remove a tooth for study. Oregon was the last state in the west to institute the mandatory check-in requirement.

Under the program, the skulls from any bear killed by hunters must be taken to an Oregon Department of Fish and Wildlife field office within 10 days of its death. ODFW biologists will use a special tool to remove a premolar tooth without breaking the roots, and a molar tooth and canine teeth will be measured. The extraction takes only a few minutes, provided the hunter did not freeze the head.

"It has to be thawed before it gets to our office before we can pull a tooth," ODFW spokeswoman Michelle Dennehy says.

More than 40 bears were checked at the ODFW's office at the Denman Wildlife Area in August, the first month of the general season. Bear tags remain available through Oct. 3 at point-of-sale licensing outlets statewide.

Hunters who freeze their bear's head should take it out of the freezer a few days before they plan their ODFW visit. It's best to leave the head on ice in a cooler to ensure no spoilage. The premolar tooth will be checked for tetracycline stains as part of a massive mark-and-recapture study on bears.

Each year, ODFW biologists put out baits laced with tetracycline statewide. By counting the baits and then counting the number of hunter-killed bears with fresh tetracycline stains, biologists can use computer models to estimate population sizes and densities.

The molar measurement will determine the bear's sex, says Mark Vargas, an ODFW wildlife biologist in the agency's Central Point office. After the tooth measurements, the skull will be tagged.

For years, ODFW relied on volunteer tooth-removal as part of its bear studies, Vargas says. For the past eight years, however, fewer than 30 percent of hunters have voluntarily checked in their bears. Oregon's 1993 Black Bear Management Plan called for check-in program to begin under those conditions.

The program applies to the general season and the spring controlled season.