The adult loon population in Northern Wisconsin has declined by more than 20 percent in the past three decades. And these days, loons are having fewer chicks.
Those are some of the findings Walter Piper presented in a recent study about the Northern Wisconsin loon population.
“It’s pretty disheartening,” Piper said.
Piper is a biology professor at Chapman University in California who studies loon behavior. To carry out his research, he and a team of scientists have captured and marked loons with leg bands since 1993.
This detailed tracking is what allowed him and his colleagues to prove a decline in Northern Wisconsin’s loon population.
There’s a caveat to Piper’s research though.
While the adult loon population is declining, the group suffering most are loons that don’t breed – what Piper calls floaters.
“Since they’re non-breeders, if you’re just watching loons out on your lake, you’re going to say ‘there’s a pair and they’re back and they’re breeding over there,’” Piper said. “And they might have a chick and they might not, but it won’t be as dramatic as if you lost your breeding pair.”
The loss of non-breeders is still a serious concern because when one member of a mating pair dies, a floater ‘floats’ in to take its place.
“If this keeps up, various lakes will start to lose their breeding pair as they die and they’re not able to be replaced,” Piper said. “And we’ll get a smaller and smaller population of loons in Northern Wisconsin.”
Why is this happening?
Piper suspects it has something to do with a drop in food availability or the rise in eagle population. Either way, humans likely play a role.
“Humans are a likely – I have to say it – a likely major player in this decline,” he said.
If there’s one thing humans can do to protect the loons, Piper said it’s to stop using lead tackle.
“It’s harmful for eagles, ducks, herons, loons, anything that eats lead is in trouble,” he said. “That would be a huge thing to boost adult survival – to just stop using lead sinkers.”
Piper said lots of adult loons were poisoned by lead sinkers this year.
To learn more about Piper's research, visit loonproject.org.