| 摘要 |
A selective bird feeder has a cylindrical, transparent feed container located inside a concentric, coaxial, transparent shroud. The shroud is supported on the container by a spring for movement between a bird feeding position and a position in which heavier birds or animals cause the shroud to block access to the feed. Perches are supported on the shroud adjacent access openings in the shroud and container. Light birds can obtain feed through the openings while heavier ones or animals cannot.
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