And of course, someone has.
"In order to maintain airspeed velocity, a swallow needs to beat its wings forty-three times every second, right?"
Actually, wrong. By comparing the European Swallow with bird species of similar body mass, we can estimate that the swallow beats its wings 18 times a second with an amplitude of 18 cm:
Check out the full article at Style.org.
Or ... you could go with the original research!
Now that I think about it, I must have posted this once before. But what the heck, it's worth repeating. :-)