It is whistling in the wind. Sound produced by the wind between the slits. Whistling, sonar. It also means cry, whine, howl, scream.
Make your voice scops owl. It is onomatopoeic and also appoints any sound that fluctuates between two or more tones, as the alarm or emergency notices, or the whistle of the wind between the trees, blinds, vents.
hoot: cry, howl, giving cries, scream, shout, ROAR, screaming, growling.