A top-fill hummingbird feeder is provided having anectar container with a liquid flow opening at a lower end and aremovable cap at an upper end, a feeding basin positioned belowthe nectar container, and a sealing mechanism associated with theliquid flow opening and the feeding basin. The sealing mechanismincludes a bottle seal assembly configured for removable couplingwith a base of the feeding basin, and a float valve captured bysaid bottle seal assembly to prevent rotation thereof whileallowing the float valve to move upwardly and downwardly withchanging nectar levels in the feeding basin. The float valveincludes a float having a frame with a buoyant member mountedthereon, the buoyant member being made of a closed-cell foam.
