Berkeley Pit: Bird Mitigation

To prevent future bird fatalities, there is now a bird mitigation program to keep waterfowl off the surface of the water. Mark Thompson, environmental engineer at Montana Resources in Butte, designed this program and said that they employ several bird deterrents. Bird mitigation workers keep watch from the small hut (pictured above at right) and shoot shotguns near birds that have landed on the water to scare them away. Automated noisemakers at the surface of the water called “Phoenix Wailers” go off every hour to deter birds from landing.

“During migration season, bird mitigation supervisors look for birds on the Berkeley Pit once every hour during daylight hours and then once every four hours at night,” said Thompson. “If the supervisors see birds on the Pit one of the methods we have to haze them is to actually take a rifle and shoot at the water near them and try and get them to leave the Pit.”


This table documenting bird fatalities from 2006-2009 shows that the 1995 incident was somewhat of a fluke.

Source: http://www.pitwatch.org

The 2016 Incident

Over the past 21 years, the bird mitigation program has been very effective. However, a recent event with thousands of geese rather than hundreds has called the system into question. On November 28, 2016, a flock of over 10,000 snow geese landed on the Pit, and fatalities were in the thousands. Like the 1995 incident, a snow storm prevented the birds from leaving the Pit, and extended exposure to the acidic water was lethal. Thompson said that new deterrents, such as unmanned aircraft, may be added to the bird mitigation program. Read more about the 2016 incident here.

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