I came into the garden on  Tuesday morning before Christmas and  heard a bunch of crows "cawing" loudly behind the greenhouse.  Continuing the morning duties of  unlocking  doors and opening  gates the sound of the crows  was replaced by   "shack, shack, shack",  a flock of Steller's jays in the same location. As  I  wandered out back to see what the ruckus was,  little woodland birds  frantically  flew left and right.  Raven sounds ,"crunk, crunk" replaced the jays.  High on a branch, through the fog, back lit by morning light, I could make out the  silhouette of a great horned owl and two ravens attacking from either side. One raven would peck high and other  low. Then the owl let out a strange sound that resembled simultaneously a hiss and a growl.  It raised its enormous wings and then flew silently away.