A "perfect storm" of a late migration and a snowstorm left thousands of snow geese dead in the toxic waters of an old mine pit in Montana last week, authorities say. A spokesman for the Montana Resources mine company says witnesses described the scene as "700 acres of dead birds" after the migrating geese landed on the contaminated Berkeley Pit water in Butte on Nov. 28, the AP reports. But the spokesman stresses that the number of birds in the area were "beyond anything we've ever experienced in our 21 years of monitoring by several orders of magnitude" and that employees "did incredible things to save a lot of birds and they really put their heart and soul behind it."
Authorities say the birds landed at the pit because their usual landing site and several others were mostly frozen, leaving the Butte site with the area's only open water. The mine company spokesman says employees are now using spotlights, noisemakers, and other methods to keeps birds away from the pit, which holds around 45 billion gallons of contaminated water. He says that the death toll is expected to be many times more than the 342 that died in a 1995 incident, when snow geese drank pit water high in sulfuric acid, the Billings Gazette reports. The company says it's continuing to monitor bird movements in the area and is looking at using technologies including drones to keep them away from the pit. (Read more geese stories.)