Botulism eats away at birds’ nervous system, first affecting their ability to close their wings and then progressing to the point where they have trouble breathing and their hearts fail. Most affected waterfowl swim offshore to seek protection from predators, but the move kills them when they can no longer hold their heads above water.
Thousands of birds can wash ashore some years; other years, such as 2008 and 2009, few signs emerged of a botulism infection.
Ray said anyone who observes dead or afflicted birds should stay away and call a local authority. Ray and others at the National Park Service try to bury the birds to keep scavengers and pets from becoming infected, since botulism travels between organisms through consumption.
It’s too soon to tell what sort of year 2013 will be, though August death rates were half what they were last year. Experts hope cold nights and cool water temperatures will push the birds to migrate south faster, avoiding major infection.
Unlike mussel-filtered water, the science is still unclear. That’s why there are several studies being performed by the U.S. Geological Survey and National Park Service to learn more about the toxin.
“We need to know more about how the toxin is getting from these microorganisms into the food that the loons eat,” said Sheridan Haack, a research hydrologist at the USGS Michigan Water Science Center.
Haack is working to analyze the gene that causes the bacteria to be toxic. Another USGS study based in Wisconsin is trying to determine where in the lakes the birds are picking up the bacteria.
“If we understand what’s happening, how the toxin is getting into the birds and understand more about why we sometimes have outbreaks and other times we don’t … (T)hen we might have a better chance of seeing if there’s something we can do to keep the birds from acquiring this toxin,” Haack said.