The Wall Street Journal featured a nice article on the silver swan automaton housed at the Bowes Museum. The swan was created by John-Joseph Merlin (1735 – 1803), a Belgian inventor and horologist. The automaton is indeed a marvel of mechanical design.
From the Wall Street Journal article:
The most complex machinery is in the neck. The movement is driven by four springs, each about one millimeter thick. There are five levers: one operates the lower bill to preen the feathers and "eat" the fish; the second operates the fish (which is concealed in the neck) that the bird appears to catch; the third allows the swan's head to nod; the fourth arches the neck; and the fifth is linked to the middle and allows its graceful movement.
Once a day, the automaton is set in motion. The bird looks left and right, then turns its neck around as if to preen the silver feathers on its back. Spinning glass rods in front of the majestic bird give the impression of a flowing stream in which several small fish seem to swim. The bird spots the fish and plunges down, beak agape, to catch one. Upon rising, a wriggling silver fish is seen within the bird's beak. After a few moments, the bird swallows the metallic fish and the show ends.
Here is the article in the Wall Street Journal about the silver swan automaton: Magic Wrought by a Merlin.
[ Thanks Bob! ]