Our feeder hangs not far from the front window. The tiny Ruby-throated Hummingbirds come and go quickly. Sometimes there are aerial duels. Wasps and hornets are carefully avoided by the little birds. I hear the birds swoop by me as I put fresh sweet water into the feeder. They have a wingbeat rate of around 50/sec (50 hertz). It is a little lower frequency than the 60 Hz hum of electric current signals I sometimes hear on audio equipment. Here is a link to an audio recording by David Eberly of two Hummingbirds near a feeder. Turn up the volume.
I was curious how different camera shutter speeds would capture the wingbeats. The camera was set on a tripod, focused through the window, and zoomed in all the way. A remote shutter let me get shots without camera shake. This first image used ISO 100 and shutter speed of 1/125 sec. Lots of blur. Even the tail feathers are blurred.
The camera was next set to ISO 1600 and 1/2000 sec to see if that would stop the wings. Individual feathers in the wings were now visible.
Wasps are frequent visitors to the feeder. They appear to be hunting for other insects crawling on the feeder. The Hummingbirds are wary. This wasp had just become airborne. The stopped motion of the wings was lucky timing on my part. Literature suggests their wings can beat at frequencies in the low hundreds of hertz.