Owls face threats from larger raptors, mammals that raid their nests, aggressive flocks of smaller birds, and a range of human-created hazards. Despite their reputation as silent, fearsome hunters, owls are surprisingly vulnerable, and the things that frighten or endanger them span the animal kingdom and the modern landscape.
Larger Owls and Raptors
The great horned owl sits at the top of the list. It is one of the most powerful and aggressive raptors in North America, and it routinely kills smaller owl species, including spotted owls, barred owls, and barn owls. Cornell Lab of Ornithology describes great horned owls as “fierce predators that can take large prey, including raptors such as Ospreys, Peregrine Falcons, Prairie Falcons, and other owls.” For many smaller owl species, the presence of a great horned owl in the area is a genuine survival threat.
Field observations of spotted owls in Oregon documented a juvenile killed by a great horned owl, with the larger owl’s molted feathers found scattered among the owlet’s remains. In several other cases, owlets simply vanished, and researchers suspected the same predator. Cooper’s hawks and goshawks also target owls. One researcher watched a female Cooper’s hawk fly rapidly toward a spotted owlet, only to be intercepted by the owlet’s father. In another encounter, a male Cooper’s hawk repeatedly dove at and struck an adult spotted owl. Even red-tailed hawks have been observed actively searching for owls after hearing their calls.
This kind of predation between raptors is called intraguild predation, and it means owls must constantly be aware of larger birds of prey sharing their territory. Smaller species like screech owls and saw-whet owls are especially at risk.
Crows and Mobbing Behavior
If you’ve ever seen a group of crows swarming and dive-bombing a much larger bird, there’s a good chance the target was an owl. Crows have what researchers describe as an innate dislike of owls, and they exploit a key vulnerability: owls are mostly nocturnal, and during the day they’re sluggish and trying to sleep. Crows take advantage of this, harassing roosting owls relentlessly to keep them awake and agitated.
This behavior, called mobbing, involves crows taking turns diving at the owl while maintaining just enough distance to avoid the owl’s talons. The prevailing theory is that mobbing may reduce the likelihood of an owl killing a crow the next time it encounters one at night. The relationship goes both ways: during the day, crows torment owls, and at night, owls hunt crows at their roosts. Jays, magpies, and smaller songbirds also mob owls, though crows are the most persistent and organized about it. A mob of crows can chase an owl out of an area entirely, forcing it to find a new roost.
Mammals That Threaten Nests
Owls that nest in tree cavities face competition and danger from climbing mammals. Raccoons are a notable threat. Research from Hokkaido University documented invasive raccoons taking over tree cavities previously used by Ural owls for nesting. The study found that tree cavities were a site of direct competition between raccoons and owls, with raccoons occupying holes that owls had used for years. Whether raccoons actively drive owls out or simply claim vacant cavities isn’t always clear, but the result is the same: owls lose critical nesting sites.
Domestic cats and dogs also pose a danger, particularly to young owls that haven’t yet mastered flight. A study of barn owls admitted to a wildlife hospital in Southeast Queensland found that “animal attack” accounted for over 26% of admissions, a category that includes pets. Owlets that fall from nests or fledge clumsily are easy targets for ground-level predators.
Traffic Noise and Roads
Owls rely on extraordinary hearing to hunt. Many species can locate prey in complete darkness using sound alone. Traffic noise directly undermines this ability. A study published in 2016 provided the first evidence that noise reduces foraging efficiency in wild owls, finding that the ability to detect prey declined as traffic noise increased. The acoustic masking effect extended more than 120 meters from a road, meaning owls hunting anywhere within that zone were at a disadvantage.
Roads are also a leading cause of owl death. The Queensland barn owl study found that vehicle impacts were among the most common causes of fatal injury, and that most injuries were fractures consistent with collisions. This pattern held across studies from both Australia and the United Kingdom. Barn owls are especially vulnerable because they hunt along road edges, where grassy verges attract rodents, and they fly low enough to be struck by passing vehicles. The study found that nearly 47% of all admitted barn owls died or had to be euthanized, and a large share of those cases involved road trauma.
Human Infrastructure and Habitat Loss
Urbanization creates a web of hazards for owls. Fences, powerlines, and buildings are collision risks, particularly for species like barn owls that rely less on vision while flying at night. Rodent poison is another serious threat. Owls that eat poisoned rodents accumulate the toxins, which can cause internal bleeding and death. Land clearing removes the mature trees owls depend on for roosting and nesting, compressing populations into smaller areas with fewer resources.
Drones and other aerial technology can also disturb owls. Larger owl species are known to respond aggressively to drones near their nests, treating them as intruders. The response varies by species, but nesting owls that are repeatedly disturbed may abandon their nests entirely.
What Owls Do When Threatened
When an owl feels threatened, it has a few characteristic responses. A defensive owl will ruffle its feathers outward to appear larger, lower its head, and spread its wings wide with the tips pointing downward. This threat posture is designed to make the owl look as intimidating as possible. Some species also hiss, snap their beaks, or sway side to side. If the threat persists, most owls will simply fly away to a safer location rather than fight.
Some smaller species take a different approach. When a larger predator is nearby, they compress their feathers tightly against their body and stretch upward, becoming thin and elongated to resemble a tree branch. This camouflage posture is the opposite of the threat display and serves a completely different purpose: avoiding detection rather than confronting danger.
Deterrents That Actually Work
If you’re searching for what scares owls because you need to keep them away from your property, the options fall into a few categories. Visual deterrents that use motion and reflected light are the most commonly recommended. Reflective scare tape, holographic owl decoys, and large “scare eye” balloons with bright colors and dangling streamers all exploit owls’ sensitivity to unexpected visual stimuli. A holographic owl decoy tested at universities showed positive results for deterring birds from specific areas.
Ultrasonic repellent devices, on the other hand, have not demonstrated significant effectiveness. Testing of combination sonic-ultrasonic devices found no measurable effect on the bird species studied, and birds tend to habituate quickly to repetitive sounds. Your best bet for keeping owls away is a combination of bright, moving visual deterrents and removing whatever is attracting them in the first place, which is usually a rodent population.