BUTTE — Over a thousand snow geese that landed in the Berkeley Pit's dangerously contaminated water this week have so far apparently survived — unlike the fate of 342 who perished in a similar 1995 landing.
Nikia Greene, the pit’s Environmental Protection Agency project manager, said Wednesday afternoon that he had seen no bird mortalities.
Mark Thompson, Montana Resources' manager of environmental affairs, agreed.
The birds apparently arrived Monday during a snow storm, Thompson said.
That was the similar scenario 21 years ago — almost to the day — when 342 snow geese showed up, but died after ingesting highly acidic pit water.
Thompson said Wednesday, however, after 30 plus hours on the water, the most recent visitors were still able to fly away. He estimated that as many as 500 took flight at first light Wednesday.
Greene confirmed that a flock of the birds flew away Wednesday morning.
More birds left the pit Wednesday afternoon in response to MR shooting rifles from both the north and southern sides. MR has been working since Monday night using various noise tactics to try to get the birds to leave.
But in the 21 years since MR and ARCO implemented a bird program to keep flocks off the pit’s water — in response to the 342 deaths in 1995 — no one has seen birds stay on the water this long, Thompson said.
Usually birds that land are gone within 12 hours, said Thompson.
Greene said he believes that about half of the geese have left since they first landed sometime Monday night. Thompson thinks there are “about 10 percent of what we first had.”
Gary Swant, of Deer Lodge, a birding expert, said heavy metals accumulate in animal tissue. That means drinking metal-contaminated water is not likely to kill the birds right away.
“It would be a chemical that would affect them immediately,” Swant said.
Necropsies of the 1995 bird deaths revealed acid had burned their throats. So it was likely the sulfuric acid in the pit that killed the snow geese in 1995.
Steve Hoffman, of Helena, executive director of the Montana Audubon Society, said the birds likely landed on the pit to rest. If the snow geese on the Berkeley Pit are thirsty, they will drink the water, Hoffman said.
Swant said the massive Warm Springs Ponds, south of Deer Lodge, a popular stopover for migrating birds, is mostly frozen. That means there is no other large body of water in the immediate area where birds could land for a rest.
Thompson said MR is working with the agencies to investigate why the birds landed on the Berkeley Pit after so many years of so few die-offs. The last count, taken in November 2013, found nine birds died in the pit in that month. Due to the instability of the pit’s walls, MR and ARCO have not been able to monitor bird mortalities in recent years.
“We’re going to figure this out because we don’t want this to happen again,” Thompson said.
ARCO spokesperson Brett Clanton said via email that they, too, are working closely with the agencies on the issue. When the snow geese landed in 1995, ARCO spokesperson Sandy Stash initially reported that the bird deaths were due to bad grain. The event gained national media attention.
Despite the tense situation, there is a potential ray of hope for the birds.
A snow storm is sweeping through Butte Wednesday night and into Thursday, said Missoula-based meteorologist Trent Smith, of the National Weather Service.
During migratory season birds fly either ahead of a storm system or they fly behind one, Hoffman said. Birds register a change in barometric pressure.
“A sudden drop may get them to want to move on,” said Hoffman.