Great horned owls are powerful nocturnal predators that are found across North America. They have large talons and wingspans, excellent low-light vision, and highly sensitive hearing that make them fierce and effective hunters. In this article, we will explore the hunting strategies and techniques used by great horned owls to catch prey.
Physical Adaptations
Great horned owls have several key physical adaptations that aid their hunting abilities:
Vision
Great horned owls have large, forward-facing eyes that give them binocular vision and depth perception. Their eyes are tubular in shape with large pupils that can open wide to let in more light in low-light conditions. The retina of their eyes contains a high density of rod photoreceptor cells which are sensitive to low light. These adaptations give great horned owls excellent night vision to help them locate and hunt prey in darkness.
Hearing
Great horned owls have asymmetric ear openings – one opening is higher than the other. This allows them to accurately locate sounds in multiple dimensions. The feathering around their face forms a facial disk that channels sounds towards their ears. Their broad wings also dampen their own sound as they fly, allowing them to hunt silently. Their excellent hearing allows great horned owls to precisely locate hidden or moving prey.
Talons
Great horned owls have large, sharp talons on their feet. Their toes have a zygodactyl arrangement with two facing forward and two facing backwards to give them an especially strong grip. They kill prey by crushing it with extremely powerful squeezed from their talons which can exert several hundred pounds of pressure. Their talons are effective weapons for seizing, killing, and carrying prey.
Wingspan
Great horned owls have broad wings with a wingspan ranging from 3.5 – 5 feet. Their large, rounded wings allow them to fly slowly and quietly as they hunt, and provide the lift needed to carry large prey items back to their nests. Their wings are specially adapted for silent flight, allowing them to swoop in undetected.
Hunting Behavior
Great horned owls exhibit some key hunting behaviors and strategies:
Perching and Watching
Great horned owls often perch on an elevated vantage point like a tree branch overlooking an open area and patiently watch for prey movement below. Their camouflage plumage helps them blend into the trees so they can watch without being noticed. A great horned owl may sit motionless for hours waiting to ambush prey.
Patient Stalking
When they spot potential prey, great horned owls will silently fly down to a closer perch and watch intently. They may hop or run along the ground to get closer before taking flight and swooping down talons-first to seize prey. Their stealthy approaches allow them to get within striking distance.
Powerful and Precise Strikes
A great horned owl’s attack is sudden, silent, and deadly. They strike prey firmly with their talons, often severing the spine with the force of their squeeze. If the initial strike does not kill the prey, they will bite the neck at the base of the skull to finish it off quickly. Their attacks are extremely accurate and efficient.
Carrying Prey Away
Once the prey is dead, great horned owls use their strong gripping talons to carry animals as heavy as 3-4 times their own weight. They fly back to a secluded perch or nest to feed. Their strong grasping toes and sharp talons lock the prey firmly in place.
Diet and Hunting Habits
Great horned owls are opportunistic predators and eat a wide range of prey:
Rodents
One of their favorite foods is rodents like mice, rats, voles, squirrels, and rabbits. They hunt rodents in open habitats like grasslands, meadows, and agricultural fields. Their excellent low light vision helps them detect and track down small mammals at night.
Birds
Great horned owls prey on many bird species, including ducks, geese, grouse, quail, and even raptors like hawks and falcons. They capture avian prey on the wing or ambush roosting birds. Their broad wings allow them to perform tight maneuvers in flight.
Reptiles and Amphibians
Great horned owls feed on animals like snakes, lizards, turtles, frogs, and salamanders. Their sense of smell helps them find reptiles and amphibians. These prey items supplement their diet.
Insects and Invertebrates
While not a primary food source, great horned owls will eat large insects and invertebrates like scorpions, spiders, centipedes, beetles, and crickets. These provide a small snack, especially during the summer months.
Carrion
They are not above scavenging already dead animals they discover while hunting. Carrion provides an easy meal they can take advantage of.
Other Birds of Prey
Great horned owls sometimes prey upon smaller raptors like kestrels and screech owls that may compete with them for food. Their larger size and strength gives them an advantage.
Breeding Season Habits
During breeding season, the hunting habits of great horned owls change slightly:
Increase Hunting
As they nurse developing chicks, the female owl’s energy demands increase significantly. Male owls must hunt more often to provide food for both female and offspring. They may hunt almost continually through the night during peak feeding times.
Larger Prey
To satisfy the increased food requirements, male owls tend to tackle larger prey items like rabbits, ducks, geese, and skunks. These provide more biomass to feed to the growing chicks.
Deliver Food to Nest
Whereas solitary owls normally eat prey where they capture it, breeding males now focus on swiftly carrying kills back to the nest to provision the female and demanding hatchlings. This continues until the chicks are old enough to leave the nest.
Hunting Habitat
Great horned owls hunt in a variety of habitat types:
Forest Edges
They frequently hunt along the borders between forests and open areas. These ecotones provide cover for perching while allowing them to spot prey movement in clearings.
Grasslands
Open grasslands rich in small rodent populations are an excellent hunting ground for great horned owls. There is little cover for prey.
Marshlands
Coastal salt marshes and freshwater wetlands teeming with birds and small reptiles are favored hunting grounds during migrations and winter.
Suburbs and Farmland
Great horned owls readily adapt to agricultural areas and subdivisions. The combination of trees for roosting and open areas for seeing prey suits them well.
Urban Areas
They can even hunt effectively in city parks, gardens, and greenbelts where their prey has also adapted to urban environments.
Hunting Seasons
Great horned owls are year-round residents across most of their range. While they hunt continually, their habits shift with the seasons:
Season | Hunting Habits |
Spring | Focus on providing food for their mates and offspring during breeding season |
Summer | Take advantage of young, inexperienced prey newly out of their burrows and nests |
Fall | Hunt migrating waterfowl and shorebirds that stop to rest and feed in wetlands |
Winter | Target rodents and rabbits whose tracks are visible in snow |
Hunting Success Rates
Studies monitoring great horned owls with attached radio transmitters have provided insight into their typical hunting success rates:
- Average around 26% success per hunting attempt on average nights
- Success rate can reach as high as 45% on peak nights of abundance like vole population booms
- Catch rates lower significantly during seasonal prey scarcity such as harsh winters
- Juveniles have much lower success approaching only 15%, improving with experience
Their versatile hunting abilities generally provide them with a steady food supply.
Adaptations to Avoid Detection
Great horned owls have several key adaptations that help them remain undetected by prey:
Camouflage
Their mottled brown-and-buff plumage blends in well with tree bark and shadows, obscuring their outline as they roost. Their underbelly feathers disrupt their body shape even further. This enables them to avoid visual detection.
Silent Flight
Specialized leading-edge fringe feathers soften and muffle the sound of air rushing over their wings. This allows them to swoop in without making noise that would alert prey.
Secondary Noise Cancellation
Their concave, disk-like facial feathers and soft ruff frame their ears and directs sounds towards them. But these feathers also help cancel out extraneous noises made by their own flight and shuffling movements.
Slow Movement
When perched, great horned owls move slowly and deliberately, rarely turning their head and exposing the front of their face. This measured movement avoids reflecting light that could draw attention.
Camouflaged Roosts
They select concealed roosting spots blocked from sight by vegetation, ridges, or hollow tree cavities. Their discreet perches keep them hidden until ready to swoop.
Methods for Locating Prey
Great horned owls utilize several methods for locating and tracking down prey:
Vision – Scanning for Movement
From an elevated perch, the owl slowly scans the ground below looking for any visual signs of movement that reveal prey – a rodent scurrying from cover, a rabbit twitching its ears, the sway of vegetation moving in an unseen animal’s wake. Their exceptional vision detects even minor motion.
Hearing – Listening for Sounds
In darkness, great horned owls rely on their acute hearing to pick up and pinpoint faint rustles in grass, chirps, squeaks, or scurrying footsteps that help them track prey. Even from within burrows and under layers of snow, their keen ears can detect signs of hidden animals.
Smell – Detecting Scent Trails
Great horned owls have a surprisingly good sense of smell that assists them in following the scent trails left by potential prey on the wind, especially for finding well-hidden amphibians and reptiles. This brings them within striking distance.
Memory – Recalling Habits and Locations
They utilize memory of terrain and stalking experience to revisit productive hunting spots where prey are abundant. Recalling locations and habits of prey improves future hunting efficiency.
Stealth and Speed of Attack
When attacking prey, great horned owls combine several advantages:
Surprise
Their silent approach, camouflage, and concealment allow them to get within striking range without being noticed. Prey often has no hint of the owl until the sudden attack.
Angle of Attack
Great horned owls swoop in at an angle, often with the moon or other light sources behind them. This keeps their shadow from flashing over prey and maintains the element of surprise.
Speed
Despite their bulky, slow appearance while perched, great horned owls can strike at speeds up to 40 mph when diving on prey. This gives most prey little time to react or flee the fatal talon strike.
Gripping Force
The crushing grip of their talons paired with momentum makes their strike immediately lethal. Prey are dispatched quickly with little chance of escape once contacted.
Biting
On the off chance their talon strike does not kill prey immediately, their sharp beak inflicts a finishing blow, severing the spinal cord at the base of the skull for a swift kill.
Carrying and Eating Prey
Once prey is dispatched, great horned owls have a couple different approaches to consuming it:
Carrying Prey Away
Often great horned owls grab hold of prey in their talons and flew a short distance away to a secure perch or nest in order to feed without competition. The bony,Sinewy muscles of their feet lock prey tightly in place aerially.
Eating Prey Where Caught
When hunting far from their nest or if prey is too heavy to carry off, great horned owls use their hooked bill to tear prey apart and consume it right where they caught it on the ground. They gulp bite-sized chunks whole.
Plucking Feathers
For avian prey, owls pluck away all the feathers before feeding. They regurgitate indigestible pellets of bones, fur, and feathers later.
Tearing Skin
For mammals and reptiles, the owls peel back the skin and fur or scales with their talons and beak before accessing the soft muscle meat underneath with their sharp bill tips.
Crushing Bones
The strong muscles of their throat and stomach contract to crack bones and digest bone marrow, providing calcium and other nutrients.
Impacts of Artificial Lighting
While great horned owls successfully adapt to man-made habitat changes like agriculture and urban sprawl, there are some concerning impacts of artificial lighting:
Disruption of Natural Rhythms
Light pollution in cities can confuse owls’ innate circadian cycles linked to natural dusk and dawn light levels. It may interfere with cues to sleep and hunt.
Revealing Owls to Prey
Illumination from street lamps and lights may make owls more visible to prey like rodents and small mammals that avoid lit areas, foiling their ambush strategy.
Attraction of Prey to Lit Areas
Prey may be drawn out into more brightly lit but risky areas, being more wary under darker cover. This exposes them more than under natural conditions.
Glare Impacting Hunting
Bright, direct lighting in an area can create glare that makes it harder for owls to spot potential prey against an illuminated background. Their vision depends on dim light and shadows.
Disrupting Navigation
Urban glow domes over cities may disrupt an owl’s ability to orient itself and navigate using moonlight, stars, and other natural light references while hunting.
Conclusion
In summary, the great horned owl is a masterful nocturnal predator. Its unique physical attributes like powerful talons, superb low-light vision, camouflage, and silent flight all contribute to making it an extremely effective hunter. Great horned owls employ skillful hunting techniques like patiently watching from perches, listening for prey sounds, stealthily approaching targets, and delivering precise aerial attacks with deadly speed and force. Although they are adaptable birds, expanding artificial lighting does impact their natural hunting abilities. The remarkable hunting skills of the great horned owl allow it to thrive as a top predatory force across many different habitats.