In a battle of enemies that dates back to before humans evolved, crows and owls have been at war with each other. Both families of birds are genetically imprinted with an intense, strong dislike of the other family. Without ever having seen an owl, a newly fledged crow instantly, aggressively, instinctually, knows in its being that it does not like the owl.
To reiterate, crows don’t like owls and owls don’t like crows. Evidence of this can be garnered first hand, especially on the Cape and Islands. Crows are abundant here, as they are over most of North America. A highly gregarious and very successful species, they have adapted to most habitats and are at home in the city or in the country. Omnivorous, they will eat almost anything.
Owls are nocturnal predators that depend on acute hearing, eyesight and special adaptations to capture primarily small rodents. They are top of the line avian predators. Most catch rats and mice and swallow them whole. Larger species, like the Great Horned Owl, may take larger prey that cannot be swallowed whole and they are one of the major predators of skunks on Cape Cod and neighboring Martha’s Vineyard.
Owls will eat crows but generally do not. Owls, despite having sharp hooked talons and meat tearing beaks, have feathers modified to be quiet in flight to aid them in homing in on food, live prey. Their feathers have soft edges which is great for nocturnal stealth flight but lousy for speed. An exception is the Arctic nesting Snowy Owl. Living on tundra where it is 24 hour daylight in summer, the birds must be able to hunt in broad daylight. This species flies as fast and strong as a falcon and can take large prey out of the air in direct pursuit. Very scary owls if you are a crow!
Crows have strong stiff feathers and are accomplished aerialists. They can out fly, out climb, out turn, in fact runs rings in the air around most owls. These birds have evolved quite differently, although both have the ability to fly. The parameters for each are very different. Not as different as a cargo plane and a jet fighter, but for the birds the difference may be even greater.
This means that they each have their strong points accompanied by intense dislike of the other. Generally speaking, owls are nocturnal, crows diurnal - so that in the normal course of events they do not encounter each other. Occasionally, however, for reasons that are usually bad and certainly indicate trouble, their paths will cross.
Crows will harass, peck, annoy and mob an owl, sometimes to the death, if they discover one in the daylight. A roosting owl discovered during the day will be brutalized and occasionally killed by a mob of angry crows. I have seen a Barn Owl flushed from its roost by eager birders from a grove of cedars along the shoreline. It was quickly mobbed by crows and unable to return to shelter. The bird was attacked mercilessly by an ever increasing mob until they managed to drive it over the ocean and into the water.
Like hyenas and lions, owls and crows are destined to not get along. Lest you think the owl never wins, that is far from the case. A number of years ago I got to inspect a crow roost on the mainland that had been predated by a Great Horned Owl. The reason the identity of the predator was known was because there were 9 dead crows on the ground in perfect condition except that the top of their heads were gone and the brains eaten. This is the signature of the Great Horned Owl: completely in charge in the night. The roosting crows were easy targets for this most powerful of North American owls.
Please don’t disturb a roosting owl in the daytime - their lives depend on it.