I had spent time on the Internet looking at marble rollers trying to get ideas and I finally settled on birds passing the marbles or ball bearings in my case. I seen one of fish passing the marbles so birds would not be an exact copy, and then I also incorporated a hand cranked pump to return the balls back up to the top.The design started by drawing a bird and making copies and placing them on a paper to work out the kinetics as seen in the picture. That is also about the time I came up with the name.
Castings would be needed so patterns for the birds were carved, and the others could be reused from previous projects.
A day of foundry work and the castings were poured. Aluminum material for melting came courtesy of neighbor Howard Gerstner's old shower stall. I had made steel cores, that also functioned as heat sinks, seen to the right. They formed the mouth and also the slot for the neck.
The "pump" was a fairly simple thing of my own design that pushes the balls up a tube.
After everything was built and put together it was taken apart and painted. Here is a picture part way through the painting process.
Finally after some very frustrating hours of adjusting it is working as it was intended during the concept stages. Some of these simple things can be as difficult as real machines to get operational.