A recent article provides more information and connects lead toxicity to other species.
A total of 8-11 dead swans were found at Sucker Lake. Four of them were retrieved and taken to the University of Minnesota Veterinary Diagnostic Lab. The results came back late last week. All 4 swans (2 males and 2 females) died of lead toxicity. Liver tissues sample results were: 41, 66, 75, and 101 ppm (parts per million). Normal levels are >1.5 ppm. We received additional reports after the earlier notice for additional swan deaths: 6 at Peltier Dam in Lino Lakes, 5 at Pickerel Lake in Lilydale Park in St. Paul, 4 at Grass Lake in Sterns County, and several at Little Pine Lake in Ottertail County. The locations are high-use fishing and historical hunting areas where lead sinkers and lead shot are accumulated in the sediment. Lead sinkers and lead shot are the optimal size for birds to pick up and use as gizzard stones. Lead is soft and is ground up in the process, becoming incorporated into their tissues as they die from lead poisoning.
Several trumpeter swans were found dead this week at Sucker Lake.
VLAWMO has taken them to a lab to study the cause of death. It is likely due to malnourishment or a hard recovery from extreme cold.
Residents walking at Sucker, Vadnais, or other nearby lakes are asked to inform us if and where they find a dead or sick trumpeter swan.
If found, please call (651) 204-6070.