You hear them all over when you're in the African bush, really funny. They are like a natural alarm system for wild animals where there's danger about. plus they really seem to enjoy their job.
This is a clip on youtube (only place I can find these things) from a movie called "beautiful people". Its from 1974 but its my all time favorite animal movie/documentary. if you like animals then you cant go without watching this movie. you can watch it over 100 times and just never get bored of it, its so so so interesting and absolutely hilarious.
Heres the clip from the go away bird
