FIVE-YEAR STUDY TO FOCUS ON ELK CALF SURVIVAL

November 04, 2001 11:00 pm
FOCUS ON CALF SURVIVAL: The numbers of yearling elk calves have gradually dropped from about 50 or 60 per 100 cows a year to as low as 10. ().
FOCUS ON CALF SURVIVAL: The numbers of yearling elk calves have gradually dropped from about 50 or 60 per 100 cows a year to as low as 10. ().

By Alice Perry Linker

Observer Staff Writer

Something in the Blue Mountains is killing too many elk calves before their first birthday.

The suspected culprits are animal predators and poor nutrition. Human hunters, however, appear to be innocent of the crime.

Researchers at the Pacific Northwest Research Station have been growing increasingly worried as the numbers of yearling elk calves have gradually dropped from about 50 or 60 per 100 cows a year to as low as 10.

Bruce Johnson, a researcher with the Pacific Northwest Research Station in La Grande, will begin a five-year study this winter of the conditions that influence calf survival.

There are a lot of species that eat neonates babies coyotes, bobcats, bear, cougar; they come to mind right away, he said.

The No. 1 suspect is cougar, although bear and coyote may eat the smallest and weakest of new calves.

Cougars are true carnivores compared to bears, Johnson said.

An accompanying factor is the quality of the animals nutrition. Poor nutrition also affects the ability of cows to nurse their young.

Research at the experimental forest shows that animals could be in poor nutritional conditions caused by high density, drought, he said. If the cows are in poor condition, they wont ovulate and wont get pregnant.

Urbanization the increasing numbers of residences adjacent to wild forests as well as a greater number of animals in a smaller area, over-grazing of grasslands and the systematic suppression of fires are the probable causes of the poor quality of grasses and other forage.

Johnson theorizes that a combination of nutrition and predators work together to cause early deaths.

To separate the two may be simplistic, he said.

The animal research will begin with tagging predators and prey in two management units of the Wallowa-Whitman Forest. By tagging young calves, Johnson hopes to learn why they die.

The first tagging will begin next spring and actual counting will start in June, he said.

If after two years we see that cougar are accounting for a significant loss of calves, well reduce the populations by 50 percent and look at survival, he said. If survival increases after that, you can say predators are having a significant effect. If cougar predation is not a significant source of elk calf mortality, we wont reduce the cougar population.

Johnson said an environmental assessment done with U.S. Fish and Wildlife indicates there will be no environmental impacts.

There may be some questions about the ethics of shooting cougars, he said.

Hunting by people probably does not affect calf survival, Johnson said. In the two units where research will take place, hunting is limited to bulls, and no antlerless elk may be taken, he said.

I dont think its anyones goal to extirpate the predators, Johnson said. Thats a social value. Wildlife management is balancing social issues.

This research is to provide information to managers so they can make rational decisions for social actions.

Elk population densities are higher than they were historically, largely because of reduced wildlife range.

They certainly used the land differently than in the past. Now they migrate into the valley bottoms, he said. Some argue there are a lot more elk and deer now than historically, but its really hard to say.