Bees, Birds and Butterflies has a post about the peregrine falcons that nest and hunt at the Port of Olympia.
It includes this anecdote from a crane operator:
"It was during nesting season, when the Peregrine pair are especially, ferociously territorial. It was near dusk; the operator was looking out over the inlet and saw a Great Horned Owl, flying low over the water, heading east and making a fatal mistake of moving near the peregrine nest box. He watched as one of the falcon pair saw the owl and took off after it with deadly intent; he saw the falcon hit the owl at high speed, driving it into the waters of the bay. The owl was unable to get out, and drowned."
(By the way, here's a Seattle P-I story I wrote about urban peregrine falcons.)