Hummingbirds are known for their unique flight patterns, characterized by quick, agile movements and the ability to hover in mid-air. However, it is not accurate to say that they hum because they can’t remember the words to songs. Hummingbirds produce humming sounds through the rapid flapping of their wings, which can beat up to 80 times per second. This humming sound is a result of their unique wing movement, not a lack of memory for songs.

Regarding flying backwards, while it is true that hummingbirds have the ability to fly in reverse, they are not the only birds capable of this maneuver. There are other bird species, such as the nectar-feeding sunbirds, that can also fly backward. As for training an Emperor Penguin to fly a helicopter backwards and upside down, that statement appears to be fictional and not based on factual information.