Owls (Strigidae and Tytonidae)
The over 200 species of extant owls are split into two classes: Strigidae (typical or “true” owls) and Tytonidae (barn owls). The barn owls have a heart-shaped facial disk highlighting their features, and unlike “true” owls, do not hoot. They screech, and many can hiss like predatory snakes, which the Strigidae can not.
A Book of Birds. W. P. Pycraft, 1908.