Recent News/Blog

Updated March 2026

 

Just a few years ago, you might have seen only a couple of mute swans on Corey Lake. Today, residents count about 30 nesting in the reeds of the North Bay and Little Corey. With their orange bills and graceful necks, mute swans look like something from a fairy tale. But their growing numbers have raised concerns among the State’s lake experts and wildlife officials.

According to the Michigan Department of Natural Resources (DNR), mute swans are an invasive species not native to Michigan. Introduced over a century ago, they multiplied rapidly — from just a few birds to over 30,000 by 2010 and an unknown but much larger number today. Michigan now has the highest number of mute swans in the U.S., with annual population growth around 9–10% before state control efforts began. Corey Lake’s increase mirrors this trend. While the sight of wildlife is part of what makes our lake special, experts warn that this unchecked swan boom can upset the lake’s natural balance - with potentially devastating effects.

 

Mute swans consume large amounts of aquatic vegetation — up to 8 pounds per adult per day, and as much as 13 pounds per day during mating season. They also uproot more plants than they eat, damaging weed beds and lily pads. Across Michigan, anglers have reported swans “virtually wipe out weed beds in some lakes,” says the DNR. This is a serious issue. Underwater vegetation isn’t just “weeds” — it’s essential

habitat for fish, frogs, and other wildlife. These plants provide food and shelter, and help filter and stabilize water. When swans overgraze, they disrupt this ecosystem.

 

 

Put simply: fewer plants means fewer and smaller fish. Healthy aquatic vegetation supports bluegill, bass, and perch, and helps keep our waters clear. “Maintaining habitat will protect fish in Corey Lake…Native vegetation and woody structure provide critical natal habitat through both cover and as substrate for invertebrate food,” says Matt Diana, Fisheries Biologist for the Michigan DNR.


Photo credit: Matt Diana

 

Unfortunately, Corey Lake’s growing swan flock is chewing through these plant beds faster than they can regenerate - most noticeably in the North Bay. Residents like Kristin Arnold and her neighbor Joan Naughton agree they’ve seen a sharp decrease in vegetation as the swan population continues to grow: “Over the past three years, the reeds in the wetland area have been reduced by about 50% and what remains is much thinner than in years past,” Arnold estimates.

 

A single mute swan can produce up to four pounds of feces per day, much of it directly into the water. That waste isn’t just unsightly—it’s loaded with harmful bacteria. A 2025 study published in Science of The Total Environment found that mute swan feces frequently contain antibiotic-resistant E. coli, including dangerous ESBL- and carbapenemase-producing strains—the kind that can make infections harder, even impossible, to treat. We wouldn’t want our children swimming in water polluted by a septic tank- yet swan overpopulation similarly pollutes our clean water, often with antibiotic-resistant bacteria.

 

Mute swans pose another threat: aggression. Despite their name, they are not silent — and they are notoriously territorial. Michigan Audubon notes that mute swans often drive away ducks, geese, loons, and even our native trumpeter swans, especially during nesting season. They have been known to attack or even kill other birds that come too close.

One example: a colony of black terns- an endangered species- in the Upper Peninsula was sharply reduced when mute swans began nesting

nearby and displaced them. The colony has yet to recover. On Corey Lake, residents have witnessed swans chasing away loons, herons, and ducks. A single pair can dominate an entire bay. Biologists also worry that mute swans are preventing Michigan’s native population of trumpeter swans — once endangered and now recovering— from nesting in suitable habitat. 

 

Trumpeter swans remain threatened in Michigan, with only a few hundred individuals statewide. They need quiet, safe lakes to nest. Mute swans are a major obstacle to their return.

 

It’s not only wildlife that mute swans confront – they can be dangerously aggressive toward people, too. North Bay residents agree the swans are highly territorial and hostile; “They and they’ve driven out the native swans, and are very aggressive to humans,” says Joan Naughton. “The swans patrol their territory and often block the passageways through the cattails and grasses in the wetlands and channel in the North Bay, says Annie Patnaude, who often kayaks in the morning as the sun rises. “I love wildlife--hearing the buzzing call of the red wing blackbird and watching the water bugs race across the surface of the water. But the swans engage in menacing behavior, lining up like sentries in a row, which can be difficult to navigate around. The message is clear- they aren’t going to yield to allow even a quiet kayaker to pass through. I can’t imagine if they were to double in number again.”

There have been numerous reports of mute swans attacking canoeists, kayakers, and shoreline residents, both in Michigan and elsewhere . Swans are huge birds (up to 30 pounds with a 10-foot wingspan . People have been knocked out of kayaks and swans have even capsized small boats.

Imagine your loved one—your spouse, your child, your sibling - enjoying a quiet moment in a kayak. Suddenly, a mute swan, fiercely territorial and unafraid of humans, charges and tips the kayak. The swan continues its relentless attack, preventing any chance of surfacing-or escape. This horrifying scenario became a reality for Anthony Hensley, a 37-year-old Chicagoland husband and father of two, who drowned as a result of the attack.

Michigan DNR confirms that every year they receive reports of mute swans attacking people on lakes – whether it’s a territorial male charging at a fisherman or a protective mama swan hiss-chasing a child who wandered too close. Public safety is a genuine concern when an invasive animal loses its fear of humans.

Mute swans can live 10 to 20 years — or longer — and reproduce rapidly. A single pair can hatch five to six cygnets each year. Without management, populations grow 9–10% annually. With around 30 mute swans today, Corey Lake’s population could double in less than a decade and quadruple by 2040 according to DNR projections. Growth is limited only by the availability of vegetation — and as long as some aquatic plants remain, swan numbers will likely continue to rise- and spread to nearby lakes. California's mute swan population has grown eightfold in 4 years:

 

 

The DNR has a program for affected lakes to help control mute swan overpopulation; this includes non-lethal options such as shaking or oiling eggs, as well as humane removal of adults- considered the most effective method by both the DNR and Michigan Audubon. Done annually by trained personnel, these methods gradually reduce population and aggression. Both control efforts require a DNR permit and majority

support from lakefront property owners to ensure broad community backing.

Mute swans are beautiful, and many of us are naturally reluctant to take action that might harm them. But as a community invested in Corey Lake’s future, we must face the facts. The scientific consensus in Michigan is clear: our current mute swan population is unsustainable.

 

Unchecked, they destroy our native vegetation- reducing fish population and impacting water quality; displace native wildlife like loons and trumpeter swans; and threaten the overall health of the lake and its residents. Acting now will help avoid the need to take more drastic steps in the future. If a company dumped a toxic substance into Corey Lake that stripped away plant and fish life, spread disease, and drove out native wildlife, we’d demand immediate action. Graceful neck or no, the end effect is the same — and if we care about Corey Lake and preserving its beauty for future generations, we can no longer afford to ignore it.