Top-fill hummingbird feeder with float valve base closure mechanism

A top-fill hummingbird feeder comprising:

• a liquid container with a liquid opening at a lower end;
• a feeding basin positioned below the liquid container for containing nectar accessed by birds;
• a sealing mechanism including a float valve, a float and a plug, the float valve responsive to a nectar level in the feeding basin for opening and closing the liquid opening, the float valve selectively covering the liquid opening of the container, and being movable between a first position in which liquid is permitted to flow from the container and into the basin, and a second position in which liquid is prevented from flowing from the container into the basin, the float being movable in a vertical direction with the nectar level within the basin for biasing the plug into and out of the first position;
• and
• a collar coupled to the liquid container and to the feeding basin, the collar having a through channel in liquid communication with the liquid opening, the plug engaging with the through channel in the second position;
• wherein the float has an open central area substantially bisected by a bridge structure and the collar includes a slot formed in a lower portion of the collar, the bridge structure aligning with the slot to capture the float and prevent rotation thereof when the collar is coupled to the feeding basin.