Several people have asked me what the swallows sound like. They have a variety of different sounds. The babies make a "cheep, cheep, cheep" sound (fast, urgent) when they want to be fed. They have a different, slower, less urgent cheep that they make after feeding, sort of a sound of contentment akin to a cat’s purring. Then there’s a different, lower pitched cheep announcing that they’re going to poop. 🙂 When I was hand feeding the little one, I got very familiar with his different sounds.
The adults have an alarm call – we heard it in chorus when they discovered the babies had been taken by the snakes. They also have a unique clicking sound that comes at the end of a series of chirps, that they make when they’re sitting in a big group on the roof or a railing, "conversing." I just love the clicking because it’s so unusual and you know when you hear it that there are swallows around – no other bird that I know of makes it.
There’s a .WAV of the adult’s chirping (with the clicking coming close to the end) at http://www.10×50.com/Sound_files/swallow_w.wav . I just played it and my cat, who was laying on the desk by my keyboard, jumped up and started trying to find the bird in the speaker. 🙂