UMATILLA, Ore. — Officials with the U.S. Army Corps of Engineers Walla Walla District have resumed use of bird-deterring lasers, and will be testing a long-range acoustic device to prevent birds from preying on endangered juvenile salmon passing through McNary Dam.

In a change from last year, the two lasers will be used simultaneously. Previously, only one of the two lasers owned by the dam were operational at any given time. One laser will be positioned on the navigational lock wing wall on the downstream side and will provide coverage of the fish outfall pipe and surrounding waters and facilities, including the dam itself.

The other laser will be positioned directly on the outfall pipe and cover the water directly below it.

The lasers, which will run from dawn to dusk daily, went into operation on April 1 and will be in operation until approximately November.

The lasers emit a bright green light that creates a large dot. Birds interpret the dot as a solid object, which they avoid as a potential threat. The lasers are programmed to move in random patterns within a predetermined area and have a range of approximately 950 feet to 1 mile, depending on the weather.

The long-range acoustic device is scheduled to begin usage in late August. A small device, resembling a common speaker, it can broadcast preprogrammed audio tracks over a large area. When activated, the tracks act as an audio deterrent for birds. Similar devices have been successful at airports across the United States.

Currently, McNary’s long-range acoustic device is programmed with two audio tracks. The first is a computer-generated male voice that announces it is a long-range acoustic device and performs a countdown. The second closely matches the noise emitted by a standard car alarm. When active, it will be audible throughout the McNary Dam and Lake Wallua area.

The long-range acoustic device will run intermittently throughout the day from late August through October. This period will serve as a trial run for the device. If the trial is deemed successful, the device will resume operations in 2022.

Safety and operational managers with the U.S. Army Corps of Engineers have performed a variety of tests on both the lasers and long-range acoustic device systems and have confirmed they pose no adverse risk to humans or wildlife.