CLARK FORK - Public access to the Clark Fork Drift Yard will be mostly prohibited this winter due to efforts to restore the Clark Fork Delta.

"For public safety that access is closed to the public right now," said Idaho Department of Fish and Game wildlife biologist Kathy Cousins.

Cousins said there is too much heavy equipment traffic at the drift yard, which poses a danger to visitors.

However, the public will still be able to visit the site on Sundays, when no work is being done in the area. The access gate will remain locked, although people can venture in on foot to collect driftwood or hike.

Hunters can still access the delta from the Johnson Creek Recreation Area. White and Derr islands are open and unaffected by the current phase of delta restoration, Cousins said.

A crane and a crew are building a floating bridge to span the drift yard log sluice channel. A second floating bridge will be installed to access an island at the face of the delta, where most of this winter's work will be focused.

For safety reasons, the public is urged to avoid the islands once crews and equipment are present on them.

Crews have also begun stockpiling materials, which include 43,000 tons of rock, 51,000 willow whips and 350 trees with a breast-height diameter of 18-24 inches.

In other delta restoration news, sonic detectors have verified six different bat species in the delta.

Cousins said the detectors picked up little brown bats, Yuma bats, long-eared bats, California bats, silver-haired bats and fringed bats.

"All of those bats are known to be in the area. It's just never been verified that they were at the Clark Fork Delta," Cousins said.

The detectors record the bats' ultrasonic chirps, which are then checked against the known wavelengths of bat communications.

Bats, along with birds and aquatic insects, can serve as indicator species for underlying environmental characteristics. Cousins is gathering the data to establish pre- and post-restoration conditions in the delta.

A bird survey has identified 75 different species in the delta, which does not include owls or a loon that was positively identified in August.

"We're thinking of doing a nighttime recording of owl calls to see if we can identify all of the different owl species," Cousins said.

The cost of restoring the delta, which is eroding due to the impact of dams on the Pend Oreille and Clark Fork rivers, is estimated at $10-11 million. Avista and the Bonneville Power Administration have each put up $3 million toward the restoration effort.

Additional funding for the work has not yet been identified.