Hungry grizzly bears and cougars near the West Kootenays community of Edgewood, B.C., are attacking and eating local sheep.

Sgt. Arnold DeBoon, a spokesman for the B.C. Conservation Officer Service, said Thursday the attacks occurred on a ranch on separate nights at the end of April and beginning of May in the rural community located northwest of Castlegar, B.C.

In all cases, the bears were captured and shot.

When the rancher moved the sheep to safety across nearby Lower Arrow Lake, though, the killing didn't end. This time, it was a cougar helping itself to the sheep.

A local ostrich also died after it ran into a fence in an apparent attempt to dodge a bear that got into a farm feed bin, said DeBoon, noting the bruin was relocated, not shot.

"Once these predators have gotten after, killed live stock, it basically restricts our options because they will continue to do that when they see that it's actually an easy way to fill their bellies," he said.

"Our policy is basically, whether it's a black bear, grizzly bear, wolf or cougar, if they're killing livestock, we basically have to euthanize them."

When bears come out of their winter dens, they head for valley bottoms where they are more likely to get new spring growth of grasses and other plants, said DeBoon.

Until just recently, though, spring has been cool, so DeBoon doesn't know how abundant that growth was.

He said the bears must have been close to the agricultural activities to catch the scent of the animals.

The grizzlies were all male, weighed between 112 and 202 kilograms, and except for the relocated bear that was old, were middle aged, he said.

"They were hungry and looking for a food source, and so they focused on what, at least at that time, was probably an easier food source and more filling than new growth in the valley bottoms," he said.

DeBoon called the situation very unusual, noting neither he nor his peers could recall having that many grizzlies, especially males, in one spot killing livestock.

Erik Espersen, owner of the Universal Ostrich Farm Ltd., said the ostrich was his, and he had to euthanize the animal after it ran into a fence and tore up its legs.

The bear wasn't bad, said Espersen.

"He didn't bug the birds or nothing, but he was just hanging around. He was actually very good. We've had griz problems before."

Espersen said one grizzly killed two birds and began eating another about five or seven years ago, noting such attacks are uncommon.

The ranch owner was unavailable for comment.

Provincial government estimates, updated in 2008, peg B.C.'s grizzly bear population at 16,000.

The conservation service office reports on its website that hundreds of dangerous grizzlies and black bears are killed every year as they forage for food.

In fact, a provincial government analysis, published in April 2004, looked at grizzly bear mortality between 1978 and 2003 and found that between 2000 and 2003, 177 bruins were killed through animal control.