Ruby-throated hummingbird - Wikipedia
en.wikipedia.org

cross-posted from: https://lemmy.ca/post/21718242

From the article:

This feat is impressive, as an 800 km (500 mi), non-stop flight over water would seemingly require a caloric energy that far exceeds an adult hummingbird’s body weight of 3 g (0.11 oz). However, researchers discovered the tiny birds can double their fat mass in preparation for their Gulf crossing, then expend the entire calorie reserve from fat during the 20-hour non-stop crossing when food and water are unavailable.

This is nuts!