Posted on Wednesday, Feb. 19, 2020 at 1:58 pm
Last week, the MFD Lake Rescue Team was dispatched to Tenney Park where a tundra swan appeared to be struggling off the shores of Lake Mendota. Animal Service Officers hadn’t seen the swan move from its location in 24 hours, causing concern for its welfare.
Deploying their airboat, Lake Rescue safely captured the swan and turned it over to Animal Services. Rescuers described the swan as "alert but very lethargic."
The story was reminiscent of another Lake Rescue call— one that took place four weeks earlier. Another tundra swan was feared to be frozen to the ice near Picnic Point. The swan wasn’t frozen. It was sick.
Hours after it was rescued, wildlife rehabilitators with the Dane County Humane Society Wildlife Center announced they were unable to save the swan. It died of lead poisoning, and X-rays revealed fishing tackle still in its digestive tract.
The swan rescued last week also tested positive for lead toxicity, with lead readings literally off the charts. Blood samples were sent off to another facility, which determined there were lead levels of 310 ug/dL in the bird's bloodstream. Levels above 10 ug/dL are considered toxic.
Even at 310 ug/dL, this swan’s toxicity is lower than the first swan's, which had a lead level of over 800 ug/dL.
The culprit, according to wildlife rehabilitators, is likely lead fishing tackle.
Fortunately, X-rays of the swan rescued last week showed no fishing tackle in its digestive tract, allowing rehabilitators to focus on getting the lead out of its bloodstream.
Using a treatment method called chelation, medications administered to the bird bind to lead and other heavy metals in the blood and remove those metals from the body. The swan began treatment last week and will be tested again this week. Rehabilitators hope they see a decreased lead level in the next round of results.
These cases prompt a call to anglers to consider alternative, lead-free fishing products when heading out to the lakes.
“Lead is in the environment already, but we don’t want to add to it,” said DCHS wildlife rehabilitator Sarah Karls.
Even the most careful anglers can lose a line or two in the water. For these birds, just a little bit of lead can cause a big, life-threatening problem. Visit the Wisconsin DNR's website to learn how you can help Get the Lead Out of our environment.
Rehabilitators report the swan rescued last week is doing well in their care, but they anticipate it will be there for quite some time.
“It’s hard to know if it’ll fully recover,” Karls said. “We’re taking it one day at a time.”