Thousands of Geese Die in a Contaminated Lake

An open-pit mine in Butte, Mont. is the scene of a grisly mass death, after cold weather forces migrating birds to land there.


Thousands of snow geese have perished in Butte, Mont.'s Berkeley Pit after landing in the contaminated water of the 700-acre, open-pit mine.

The geese were forced to land there after nearby lakes commonly used by the birds became frozen over, Montana Standard reported.

Estimates so far, based on overhead counts, are that some 10,000 geese first landed in the pit's waters on November 28.

Berkeley Pit, managed by Atlantic Richfield (Arco) and Montana Resources (MR), was once an open-pit copper mine that is now managed as a federal Superfund environmental cleanup site. Its highly acidic waters are filled with chemicals from its rocks.

A similar mass-death of geese occurred at the site in 1995, when more than 300 of the birds died after landing at the pit and drinking the water. Officials expect the current death toll – still being assessed – to be higher than that incident.

The Berkeley Pit is one of the largest Superfund sites in the US. It is a toxic lake a mile long, a half mile wide, and nearly 1000 feet deep filled with heavy metals and toxic water from old underground copper mine shafts in Butte, Mont. Credit: William Campbell/Corbis via Getty Images

The lake is considered too big to make practical the use of equipment such as netting to discourage the birds from landing there, although noise-based programs designed to scare them away have shown some success, Montana Standard noted.

Officials are still working on a final death total, as the mine's walls are considered too unsafe for workers to get closer to the scene by boat. Counts, then, must be taken by drones and airplanes overhead. Also yet to be determined is whether or not any Environmental Protection Agency fines would be warranted, should pit operators be found not to have correctly followed "hazing" policies designed to keep geese from landing at the site.

Since the mass-landing, pit managers have been using lights and other loud noise sources to scare other geese away from alighting in the lake.

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