Listen to a pair of black swans. I don't quite know what to call this sound... Wikipedia says "The black swan utters a musical and far reaching bugle-like sound". It's not a quack, or a honk, or a tweet.
Anyway, check out the noise these black swans make. By the way, the roaring sound in the background is from some animatronic dinosaurs that were on display at the zoo.
Video taken by Skyenimals owner at Oglebays Good Zoo in Wheeling, West Virginia.
