Crows are constantly communicating with one another. This is one stratagem of their success. Their calls indicate danger, food, recognition and contact and are critically important to the psyche of the species. Crows begin their daily communications with each other from the first hint of dawn until dark, a habit that together with their propensity to favor suburban settings has earned them no human friends in suburbia. The screaming, scolding and assembly calls that reverberated through the woods as the mob of crows pursued the horned owl mentioned previously served to alert and inspire all crows within hearing of the presence of the single most feared predator of all crows, the great horned owl.
Owls take good advantage of the crow's habit of spending the night in large, communal roosts.
Moving in on silent wings under the cover of darkness, the horned owl easily moves from perch to perch , casually plucking off crows right and left. With such easy pickings afforded to him, the owl commonly rips the head off his unfortunate victim, swallows it in one gulp, and moves along,discarding the rest. After a couple of crows have been thus dispatched, the satisfied owl departs, leaving the rest of the crows, as one may imagine, in a somewhat terrified state. However, if and when the crows discover an owl unprotected during daylight hours, all hell breaks loose and every crow for miles assembles in an attempt to kill, or at least drive off the demon. A large, heavy-set, all black bird.