I put on new bellows.
The one bellows (left from clock back) is pushed up by the cam, the second bellows (right) is lifted up by a wire from the left bellows, the right bellows locks a kick-stand wire in place to hold it up and the left bellows knocks off the right bellows kick-stand at the bottom of the left bellows travel. Thus: cuck- coo- as two separate consecutive sounds. The bird’s tail is moved up and down with square loop from the right bellows.
and now the hard part, tweaking the mechanism to work dependably again.