Just like conventioneers, they were visitors only for the day. They arrived Wednesday morning (5/25/16) and appeared to leave by nightfall.
A group of swans is called a bevy. When they take flight, they become a wedge.
This bevy appeared to consist of 12 mute swans. They spent their time bobbing their heads below the surface, likely looking for something to eat. They spent time roaming the middle of the west end of the lake and at one point headed for the shallower waters of Pierce’s Bay.
Swans have been a topic at Clark Lake, sometimes a controversial one. In the past, a swan that had become aggressive was eliminated by the DNR. You can review swan stories on this website–there are about 20 of them.
Bill Leutz noticed the bevy from his front deck and photographed them. Below is his photo.