The swan, which is life size, is a clockwork driven device that includes a music box. The swan sits in a "stream" that is made of glass rods and is surrounded by silver leaves. Small silver fish can be seen "swimming" in the stream.
When the clockwork is wound the music box plays and the glass rods rotate giving the illusion of flowing water. The swan turns its head from side to side and also preens itself. After a few moments the swan notices the swimming fish and bends down to catch and eat one (ornithologically inaccurate, as swans do not eat fish). The swan's head then returns to the upright position and the performance, which has lasted about 40 seconds, is over. To help preserve the mechanism the swan is only operated once each day at 2pm.
The swan was described in a 1773 United Kingdom Act of Parliament as being 3 feet (0.91 m) in diameter and 18 feet (5.49 m) high. This would seem to indicate that at one time there was more to the swan than remains today as it is no longer that high. It is said that there was originally a waterfall behind the swan, which was stolen while it was on tour.
It is known that the swan was sold several times and was shown at the World's Fair (Exposition Universelle (1867) held in Paris, France. The United States novelist Mark Twain observed the swan and recorded his observation in a chapter of the Innocents Abroad.