Hummingbirds make humming sounds created by their beating wings which flap at high frequencies audible to humans. Did you know they can also make a noise similar to a snore? A female Amethyst-throated Sunangel sleeps as a machine measures how much oxygen she consumes. The bird was later released unharmed by the researchers.
They believe that the bird was in the early stages of arousal from deep torpor after disturbance. The gaping of the bill is a way for the bird to bring in more oxygen to warm its body. The high-pitched sound is a cute side effect.