Opel Mok saw through the nesting of a pair of Spotted Doves (Streptopelia chinensis) on a pot of mint plant in his porch (1, 2). Weeks after the chicks fledged, the adults returned with their fledglings to the nesting area, much to the delight of Opel and his wife. So they left food for the birds to feed on.
Opel subsequently constructed a crude feeder made from an old soft drink bottle glued to a base (below left) and filled with a commercial bird feed (left; below centre) that cost him S$1.50 per packet. This worked fine and the returning birds had a constant supply of feed (below right). In fact the birds ate and ate, finishing a bottle within two days… and in the process messed up the place… and left Opel annoyed.