Falk Keuten of the Spiel und Kunst mit Mechanik blog posted this video of a German tin toy bank made by toymaker Lorenz Bolz. A coin is placed in front of the opening in the birdhouse. When the hand-crank is turned, the bird emerges from the hole with its beak open. In a quick movement, the bird closes its beak on the coin, and flips back into the house. The telltale sound of a coin hitting tin lets us know that the bird has dropped the coin inside.
The second half of the video reveals all the mechanical details that allow this to happen. In many similar mechanical toys such as the toothpick dispensing birds and cigarette dispensing birds, the beak is not articulated, but has a tapered opening. The pressure of upper and lower portions of the beak hold item by friction. It's up to the user to remove the item because the beak itself cannot release it. This mechanical bird bank is different and more complex than that.
It's a truly ingenious little machine. I am certain that if I were asked to design the mechanism, it would be far more complex and cumbersome, and no more reliable.