MADISON, Wis. (WMTV) -- The Madison Fire Department is asking anglers to stop using lead-based fishing tackles after a tundra swan was poisoned but survived and another swan died after swallowing such tackles on Lake Mendota.
The first incident happened last January, when MFD's Lake Rescue Team was called onto the waters to help a tundra swan that appeared to be stuck on the ice.
But the rescuers soon discovered that the swam wasn't frozen, but sick. Some time later, the swan passed away.
Tests concluded that it had died from lead poisoning, from a fishing tackle stuck in its digestive system.
Then, just last week, the Lake Rescue Team was once again called out onto Lake Mendota to help a second tundra swan, which appeared to be struggling off of the shore.
That swan is now undergoing treatment, but experts say it has a long road to recovery.
"Most swans do go south, but the ones with lead positioning, it affects their mental abilities, it affects their energy levels, they're always very lethargic," says Tessa Collins, a wildlife rehabilitator with the Dane County Humane Society's Wildlife Center.
Collins says both swans showed irregular amounts of lead poisoning.
"[The first swan's] lead was over 800 micrograms per deciliter. We treat anything over 10. So that's considered a concerning level, is 10 micrograms per deciliter. And having 800 is huge," she says.
The Dane County Humane Society's Wildlife Center has never rescued a swan that was without lead poisoning. Experts have also seen lead poisoning in geese, ducks, turtles, opossums and eagles.
"The best thing we could do to stop finding these swans and geese and other animals with lead poisoning, is to stop using lead as much as we possibly can," Collins explains.
The burden now falls on hunters and fishers to find alternatives to lead shots or lead sinkers. Such a change could protect more than area wildlife.
"If lead is accumulating in the environment in small amounts, in fish and water fowl and other animals that pick it up from the environment, that lead could be transferred to people who consume those animals," Collins tells NBC15 News.