A liquid nectar hummingbird feeder has a reusable base with a feeding basin that receives a disposable cartridge containing a pre-filled volume of liquid nectar. The cartridge has a single bottleneck opening at a lower end which is initially sealed by a breakable seal in the form of a film layer of foil, coated paper stock, plastic or the like. The base includes a cartridge mounting and opening structure adapted to secure and open the cartridge bottleneck opening by rupturing the film layer seal to allow liquid nectar to flow from the cartridge into the feeding basin.