Our human eye’s blink speed will serve as a reference point of “relativity” for this gallery.
70 flips of a wing per second to human’s blinks of .3 per second 1/3 of a second is one blink of the eye.

Therefore the hummingbird flaps 21 times in the same timeframe as the blink of an eye. (70-flaps * .3 of a second)

21 times in the blink of an eye