The only bird that can fly backwards for any length of time is the hummingbird. This is due to the unique structure of their wings, which have a ball and socket joint that allows for a greater span of movement, freeing their wings up to move in all directions. As well as allowing them to move their wings in a figure of 8 movement that means they can hover in one spot, this is what lets them fly backwards. Other birds, such as herons, egrets, flycatchers, and warblers, can flutter backwards for a short distance as a defensive strategy, and some birds, such as cuckoos, if they are flying against a strong wind, appear to be flying backwards, but relative to the air they are moving forwards.