Robert Paul Lieb, James Roberts Obenshain: Bi-modal seed port for bird feeder. Cedar Works, Neal O Willmann, June 25, 2002: US06408788 (36 worldwide citation)

A seed port, intended to permit dispensing large and small seeds from the same feeder, can be used with a bird feeder having a columnar reservoir for the containment of bird seed wherein the seed port has a platform with an opening that attaches to the reservoir in alignment with an opening in the r ...