Hummingbird top-fill feeders are popular among bird lovers because they are easy to fill and clean and also because they do not need to be turned upright which means that there are less chances that the nectar is spilled. The sports bottle top-fill hummingbird feeders have the design of a sports bottle, with a mechanism that works similarly to such a bottle. With this type of feeder, one has to push down the plastic container in order to close the nectar reservoir and then to unscrew the cap and pour the nectar. After the cap is replaced, the body of the nectar reservoir can be pulled up. This type of bird feeder has the advantage that the feeder does not need to be turned upside down to be refilled and which results in less nectar wasted by spilling. The traditional top-fill hummingbird feeders are one of the most popular types. There is also a plunger type of top-filling hummingbird feeder which comes with a small plunger in the container that creates the vacuum seal when the lid is tightened and the nectar will start flowing only when the lid is sealed correctly to the feeding ports.