A beautiful invasion

Post by Kelsey Roehrich

I am a student at Iowa State University, and traditions are an important part of school life. One long-standing tradition centers around two swans, Lancelot and Elaine, which float on a small campus lake. Legend has it, walk around the lake three times with your significant other and you will be together forever, since it is said that swan pairs mate for life.

During my time as an intern for the Lake County Forest Preserves in Illinois I have learned a lot, but I never thought I would debunk one of my university’s traditions! Lancelot and Mute swans in Libertyville, ILElaine are mute swans (Cygnus olor), and I found through research that mute swans can have up to four different mates and will often “divorce” each other. Perhaps this is the reason that the tradition may not have worked out for some couples.

Good news for you “love birds,” occasionally mute swans choose only one mate, and those couples typically have a more successful mating season. So not all hope is lost, but as for me, I won’t be making three trips around the lake any time soon.

Mute swans are not native to the United States. They were first introduced to North America in the late 1800s from Europe and Asia for use as living decorations on ponds and lakes, just as they are on Iowa State’s campus. The consequent expansion of mute swans poses significant threats to native wildlife through competition for food, territories and nesting areas. These large birds consume four to eight pounds of aquatic vegetation each day and can uproot about twenty pounds daily. This can rob other animals of food.

Mute swans are territorial and aggressive, especially during mating and brood-rearing season. They drive off other water birds and will attack humans who approach too closely. In 2012, an Illinois man in a kayak got too close to mute swans on a small pond. The swans charged at the man’s kayak, causing him to fall into the water. The swans continued to harass the man, and he drowned before reaching shore. Mute swans are one of the most aggressive waterfowl species. They set up large territories, which can encompass an entire small lake or pond. These combative swans chase off other waterfowl, displacing native species from their nesting and feeding areas. Wildlife biologists are concerned about the decline of native waterfowl species in some areas, such as trumpeter swans.

swan_id

The population of mute swans in North America has increased steadily since it was first introduced. There is controversy surrounding the control of non-native mute swans in areas where native wildlife habitat is threatened. Some states, such as Michigan, Minnesota and New York have set policies and goals to manage, and in some cases, eliminate the mute swan population.

As I work on various projects for the Forest Preserves, I’m constantly learning more about their conservation efforts. Unfortunately, the story of non-native, invasive mute swans is just the tip of the iceberg. Invasive species, from the emerald ash borer to garlic mustard, are an issue everywhere, but there is hope! Knowledge is power, and we can all help. Restoration workdays are held every weekend. Visit www.LCFPD.org/restorationworkdays to find upcoming opportunities to make a difference. Instead of circling the lake on campus three times, perhaps I can find my future beloved while restoring the ecosystem…

6 thoughts on “A beautiful invasion

  1. Good information on swans. Did not know that there were three species. I do know I prefer swans in our ponds and small lakes over the suburban species of Canada goose!

  2. I can attest to the aggressive power of a mute swan’s wing. Was once photographing one that had been frequenting detention ponds in my neighborhood, not realizing that his mate was nesting in the reeds and cattails nearby. When I sat on the grass to reload my camera (the good ol’ film camera days), the male turned on me with an outstretched wing. I tried to make a run for it, but it caught me first in the shin, which brought me back to the ground (I thought my leg might be broken), and then in my arm. The wounds were a lot more severe than most people would think.
    I did get some breathtaking shots, but, sadly, I eventually found the nest empty of the female and her eggs — all that remained was part of a leg bone, which was banded.

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