By David Marks, Wildlife Biologist, USDA Wildlife Services
People live on the water for many reasons including the appeal of being close to nature. Mute swans are beautiful animals and many people appreciate having a family group to watch. But it is an invader to Michigan waters that may potentially threaten the natural value of the places you care about.And as the mute swan populations have grown, people are beginning to experience their negative effects on the environment, native wildlife, and even human safety. Destruction of native habitat is the primary concern about mute swans.Feeding on aquatic vegetation, a single bird can eat up to eight pounds per day. Thus, a large group of swans in an area can drastically affect the habitat that other wildlife species depend on. Additionally, the mute swans out-compete native species for resources, both food and breeding habitat.If your lake is highly developed and lacks native habitat and wildlife, you may wonder why mute swans should concern you. Consider the bigger picture: the mute swans on your lake will continue to be a source of more mute swans, which will spill over into high-quality wildlife areas.
Individual mute swans can also become hostile towards humans and pets. This usually occurs in older male mute swans that are protecting their nests and cygnets. As years go by, an individual male may become more and more assertive.Aggressive behavior may begin as simply hissing and swimming around a person to deter them. But sometimes the behavior escalates to flying at people when unprovoked or actually making contact with people, and the birds become a significant threat to human or pet safety. If this situation does occur, a special permit can be issued to remove that particular aggressive swan.
Basically, two options exist for mute swan population control: removing the birds or treating their eggs so they will not hatch. Removing the birds is more effective as far as reducing the numbers of swans both on the site itself and the overall mute swan population in Michigan.However, some local residents may find it unacceptable because the birds will be killed.Egg treatments may be the only option acceptable to residents, and will gradually reduce the local mute swan population if conducted annually and will help reduce aggressive behavior towards humans during the summer.Relocation of mute swans is not an option because they are an invasive species and will just cause damage at another location or even fly back to the original site.
Since 2006, USDA Wildlife Services has been working cooperatively with the Michigan Department of Natural Resources in controlling the mute swan population throughout Michigan, with support from a broad range of stakeholders. These include the US Fish and Wildlife Service, several Native American tribes, Ducks Unlimited, the Michigan United Conservation Clubs, the Michigan and National Audubon Society, and the Michigan Lakes and Streams Association to name a few. Wildlife Services conducts mute swan management through funding provided by a Great Lakes Restoration Initiative grant, at no cost to the landowner(s). In 2013, Wildlife Services conducted management and resolved mute swan conflicts at 76 sites throughout Michigan.
If you would like to learn more about mute swan impacts and what options you have, you can turn to several resources. The best resource is the State’s website at www.michigan.gov/muteswanswhich has the facts about mute swans, including a list of peer-reviewed scientific literature, as well as the laws and regulations and permit applications. To discuss the specific issues of your mute swan situation, you can contact your local MDNR biologist (online list) or a USDA Wildlife Services biologist (517-336-1928). USDA Wildlife Services works with the local parties to resolve their conflicts with mute swans and only conducts management actions at the request of the locals from that lake or river.