European or african swallow? by Pierre Pichot Photography, on Flickr, 500px or my portfolio
Can't resist based on your title (Monty Python - The Holy Grail):
S #1: Where'd you get the coconuts?
A : We found them.
S #1: Found them? In Mercia? The coconut's tropical!
A : What do you mean?
S #1: Well, this is a temperate zone.
A : The swallow may fly south with the sun or the house martin or the plover may seek warmer climes in winter, yet these are not strangers to our land?
S #1: Are you suggesting coconuts migrate?
A : Not at all. They could be carried.
S #1: What? A swallow carrying a coconut?
A: It could grip it by the husk!
S #1: It's not a question of where he grips it! It's a simple question of weight ratios! A five ounce bird could not carry a one pound coconut.
A: Well, it doesn't matter. Will you go and tell your master that Arthur from the Court of Camelot is here.
S #1: Listen. In order to maintain air-speed velocity, a swallow needs to beat its wings forty-three times every second, right?
S #1: Am I right?
A: I'm not interested!
S #2: It could be carried by an African swallow!
S #1: Oh, yeah, an African swallow maybe, but not a European swallow. That's my point.
S #2: Oh, yeah, I agree with that.
A: Will you ask your master if he wants to join my court at Camelot?!
S #1: But then of course a-- African swallows are non-migratory.
S #2: Oh, yeah...
S #1: So they couldn't bring a coconut back anyway...