By Ron Brown
June 13, 2011
WHITE CITY, Ore. -- Oregon Fish and Wildlife biologists are out in the woods of southwest Oregon this month, putting bags of pungent bait in trees, hoping to lure in a bruin as part of a statewide study.
The bacon bait contains a harmless chemical that will later tell scientists some key factors about those bears to help manage and protect them.
For the past week or so, Mark Vargas and other ODFW game biologists have been heading into the woods of Southern Oregon, hanging out small mesh bags of old bacon and grease that may be pungent to us, but is almost irresistible to bears. Inside the rolls of bacon is a tetracycline capsule that stains bears teeth for later study. Most of the bears are killed by hunters, landowners protecting their property, or vehicles along roads and highways.
Mark says, "What it does in the bear's system is it gets in there and it will lay a calcium layer in their tooth, as their tooth in developing. Every year the bear lays down an annual ring in it's tooth."
Kind of like the rings in a tree. A microscope image of a slice of a tooth shows the calcium layers stained by the tetracycline.
So, when a hunter kills a bear, or one is found as a road kill, it's brought to an ODFW office where it's measured...like this one that came in over the weekend, and a small tooth removed for study and the bear's last location noted.
Mark says, "Last year between hunter harvest, damage bears, human safety bears and road kill, we checked into our office about a little over 300 bears."
He says without hunters and others bringing in bears, or notifying ODFW where a bear is dead, they couldn't do an accurate study. Partially as a result of doing this study for nearly 13 years, they are able to estimate the state bear population at 25-to-30,000.
Scientists say only about a third of the bait bundles are taken by bears, birds or other small animals eat the rest.