“A female Amethyst-throated Sunangel (Hummingbird) sleeps in Peru. It’s likely that this bird is in the early stages of arousal from deep torpor after disturbance. The gaping of the bill might be a way to breath deeply and bring in plenty of oxygen. When they are disturbed in torpor, they try to warm up as quickly as possible and that involves intense shivering. But initially, they are too cold for high-speed muscle action so it’s hard to see the shivering movements. The high pitched squeaking sound it is making is likely a cute side-effect of the gaping for oxygen. The noise is actually a lot more quiet than it seems, for whatever reason my camera picked it up and made it sound a lot louder. This experiment was performed with the guidance and supervision of some of the top experts in tropical ornithology. This bird was not harmed whatsoever, it was fed with sugar water throughout the experiment and was released safely. After the experiment was done, I watched the bird fly away myself, it was fine.”