Grizz'ld and Gone....

[JoseCuervo]

They probably all walked over to Idaho and became the "Flesh Eating Carnivores" that Gov. Kempthorne warned us about...

Trying to gauge the health of the grizzly bear population in and around Yellowstone National Park, biologists last year found fewer females with cubs compared with a record number in 2002. They also found a slight decrease in the number of grizzlies killed by people.

But wildlife managers caution against reading too much into figures from a single year.

"Any one of these criteria is not going to give you the full picture," said Chuck Schwartz, leader of the Bozeman-based Interagency Grizzly Bear Study Team.

Observations of female grizzlies with cubs - an important indication about how well the overall population is faring - dropped from 52 in 2002 to 38 last year, according to the grizzly study team's annual report. More than likely, that drop is tied to a poor food year in 2002 and a slight reproductive increase in recent years that left few females available to breed and show off their offspring in 2003, Schwartz said.

"It's no cause for concern," Schwartz said. "It's just normal environmental noise, and we'll probably see slightly higher counts next year."

The recovery of the bear population is about more than numbers, biologists say. It has more to do with available habitat, tolerance by people and the food supply.

Even so, wildlife managers are charged with trying to count bears.

Each year, biologists track grizzlies inside Yellowstone and the surrounding areas outside the park. The survey is aimed at creating a snapshot of the grizzly population. In particular, they document the number of adult female grizzlies accompanied by cubs of the year.

Over time, the surveys help establish population trends. Since 1983, bear trackers estimate that the population has increased about 4 percent a year, and grizzlies are consistently trying to move into new areas. Federal officials say there are probably 550 to 600 in and around Yellowstone.

Inside Yellowstone, bears probably occupy about as much of the landscape as they can, Schwartz said. When that carrying capacity is reached, grizzlies start reproducing in smaller litters, and some begin wandering farther to find their own piece of land to call home.

"So bears are expanding their range," he said. "But it's not like they've picked up and left and we've got an empty hole in the middle."

Outside Yellowstone but within the adjacent recovery zone - a buffer of national forests and other public land that is relatively undeveloped - the population is growing by about 7 percent a year, Schwartz said.

"That's where we still have space for bears," Schwartz said.

Beyond the recovery zone, grizzlies start running into more private land and, soon, more trouble. Schwartz said death rates for grizzlies outside of the recovery area outstrip reproduction - a situation referred to as a "mortality sink" by biologists.

Studies will try to isolate the factors that most affect grizzly mortality, including road density and land development.

In 2003, 11 grizzlies in the Yellowstone ecosystem died from human causes, such as being hit by a car or shot. The figures from 2003 are the lowest since 1999, when seven grizzlies were reported dead because of people.

In tracking females with cubs in 2003, bear biologists found that most were seen in the southern portion of the ecosystem. But the survey was limited last year by several factors, including wildfires that clouded aerial sightings.

Still, the count of 38 matches the average between 1997 and 2002, according to the bear report.

The population also may have been hindered by a downturn in 2002 in production of whitebark pine nuts, a key food source for grizzlies in the Yellowstone area. Nut production ebbs and flows year to year, affecting bear behavior and reproduction cycles.

The crash in 2002 could have meant that females did not build up enough fat that fall and, subsequently, did not complete their pregnancies, Schwartz said.

"Periodically we'll see a poor food year," he said. That may cause a temporary dip in the population, he added, but shouldn't overshadow the overall progress in recent years.

"In general, the long-term trajectory shows those counts have been going up," he said.