Next time you hear thunder...

Next time you hear thunder on a sunny day, look around for hummingbirds. As this article points out, if you adjust a hummingbird's speed based on the ratio of its length to the length of a jet, the hummingbird goes faster:

"When measured relative to the length of their bodies, the birds' top speed, [Christopher Clark] said, was 'greater than [that] of a fighter jet with its afterburners on, or the space shuttle during atmospheric re-entry'.

That sonic boom you hear may just be a hummingbird trying to find its mate!

Incidentally, if you adjust my walking speed (approximated at 4 mph) by my length while walking (approximated at 12 inches), I'm faster than the Boeing 747-100 (231 feet, 10 inches long, cruising speed of 555 mph). My adjusted walking speed would be 12/((231*12)+10) * 4mph = 927 1/3 mph. Wow! I just broke the sound barrier, too!