| 摘要 |
A trapdoor for a birdhouse, particularly one constructed to attract purple martin birds, so as to trap in a compartment of the house species of undesirable birds, such as sparrows. The door includes an opening to permit the undesirable birds to enter a compartment of the birdhouse. A pivotal gate is secured to the door behind the opening and is retained by a trigger mechanism in an unblocking position above the opening. When a bird enters the compartment through the opening and alights on the trigger mechanism, the gate is released and drops by gravity across the opening to trap the bird within the compartment. The trapdoor includes structure for positively locking the gate against inadvertent pivotal trapping movement should the birdhouse or trapdoor be moved or displaced.
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