Swans have taken up residence at Clark Lake, and project a majestic image. So when one dies, it is noticed. Recently, as many as four dead swans have been reported floating or washed to shore. Unless obvious physical harm is apparent, the cause is difficult to determine.
This website has reported on this topic in other years. This excerpt from November 11, 2013, described finding a dead swan at Ocean Beach and pointed to a possible cause. This could have relevance to the current situation.
“A few years ago, some swans died and floated down the lake much like this one. John Deming contacted the DNR and asked them to investigate. The DNR indicated cause of death was due to ingesting a “fluke” (otherwise known in some circles as “Verminous Hemorrhagic Ulcerative Enteritis”).
Has something similar happened to the four that perished this winter? The Michigan DNR offers this:
“Mortality attributed to this parasite has been on the increase in waterfowl nationwide and in mute swans in Michigan either due to an increased awareness of the disease or because of an actual spreading of the parasite.
“Some of the mortality we have seen in Michigan’s waterfowl has occurred during periods of migration, which agrees with what several other authors have seen in various areas of North America. However, the resident, non-migrating mute swans that are present throughout the state have died from this parasite during all times of the year. The parasite may become a population-limiting factor to some mute swan flocks in the future.
“No reports of human infection have been reported for this trematode.
Short of an autopsy, this explanation could be correct.
Clark Lake hosts mute swans, and you can determine this by their distinctive, orange bills. They are also considered to be an invasive species. Why? Click here to see what the DNR says about them.
More on swans at Clark Lake:
Additional stories about swans can be found under Natural Encounters on this website, or use the search word “swan” at the magnifying glass.