Owls make clicking noises with their tongues, often as part of a threat display. They can also make a loud, 3-4 second hiss at intruders or predators that disturb the nest.
Owls have a very wide range of vocalizations, ranging from the hoots so often associated with Owls, to whistles, screeches, screams, purrs, snorts, chitters and hisses. Hooting is often territorial, and is also associated with courting, the male usually having the lower pitched Hoot. It should be noted that not all owl species Hoot.
They may also clap their wings in flight as part of a mating display.
Owls have a very expressive body language. Many species will bob and weave their head, as if curious about something - this is in fact to further improve their three-dimensional concept of what they are viewing. Learn more about owl behaviours at Owlpages.com.
With over 200 species living on every continent except Antarctica, owls have super-tuned senses that help them hunt prey all over the world. Check out these 15 mysterious facts about owls shared by Mentalfloss.com.