Screech-owls are small to medium-sized owls found throughout most of North America. They get their name from their eerie, shrill calls that can often be heard at night. Screech-owls hunt a variety of small mammals, birds, and insects, but one of their more common prey items is the eastern gray squirrel. So do screech-owls eat squirrels? The simple answer is yes, screech-owls are known to prey on squirrels quite frequently. However, the details of this predator-prey relationship are more complex.
Screech Owl Diet
Screech-owls are opportunistic hunters and will eat just about any appropriately sized prey they can catch. Their diet includes:
- Small mammals – mice, voles, shrews, bats, rats, squirrels, chipmunks, etc.
- Small birds – songbirds, woodpeckers, sparrows
- Reptiles – lizards, snakes
- Amphibians – frogs, salamanders
- Large insects – beetles, moths, crickets
- Worms and other invertebrates
They hunt mainly at night by perching on an elevated roost and swooping down on prey. Their excellent low-light vision and keen hearing give them an advantage when hunting in darkness. Screech-owls swallow small prey whole and carry larger items, like squirrels, back to their nest to eat in bites.
Squirrels, specifically the eastern gray squirrel which is widespread in eastern North America, are a very common prey item for screech-owls because of their abundance and vulnerability. Screech-owls prey on juvenile, adolescent, and adult squirrels opportunistically when they can ambush them.
Do Screech Owls Target Specific Squirrels?
Screech-owls are not particularly picky about which squirrels they eat. They will prey on any gray squirrel they can surprise and overpower. Some key factors influence screech-owl predation on squirrels:
Age
Younger squirrels are much more vulnerable to screech-owl predation. Juvenile squirrels just emerging from the nest and adolescent squirrels venturing out on their own are more likely to be caught by a hungry screech-owl than mature, wily adults. Younger squirrels lack survival experience and tend to take more risks.
Time of Day
Screech-owls hunt at night, so nocturnal squirrels active in the late evening and pre-dawn hours are most at risk. Diurnal eastern gray squirrels that are still outside of their nests after dark or leave the nest before sunrise have higher odds of encountering a screech-owl.
Location
Squirrels out in the open away from the protection of trees and bushes are more exposed. This includes squirrels crossing lawns, roads, and other open areas. Squirrels foraging on the ground are also easier targets than those safely up in trees.
Weather
Squirrels caught out in the rain or heavy snow may seek shelter in more vulnerable locations. High winds can make it hard for squirrels to hear approaching danger as well. Conditions that impair vision and hearing make squirrels much more susceptible to ambush.
So while screech-owls aren’t picky between squirrels, circumstances can make certain squirrels much higher risk targets.
How Do Screech Owls Catch and Eat Squirrels?
Screech-owls have a varied hunting strategy to catch squirrels and other prey:
Perch Hunting
Screech-owls often survey an area for prey from an elevated perch like a tree branch, fence post, or power line. They watch for any movement and listen intently for squeaks, rustling, and other prey sounds. Once a target is identified, the owl waits for just the right moment to launch an attack. Using the element of surprise, screech-owls can swoop in, grab a squirrel with their talons, and carry it away.
Still Hunting
Screech-owls also hunt while flying slowly through an area scanning the ground. This allows them to cover more area when prey may be scarce. A squirrel foraging out in the open may easily be spotted from the air and dove upon.
Active Hunting
When other techniques fail, screech-owls may actively flit between trees looking for signs of movement or wander on the ground poking their heads into bushes and hollow logs to startle hidden prey. This uses more energy but increases their odds of finding a meal.
Caching Prey
Once they’ve caught something, screech-owls often carry squirrels and other sizable prey to a secluded cache site like a tree cavity or shrub thicket. Caching helps keep other predators from stealing their meal and provides leftovers for later.
Feeding
For smaller prey, screech-owls simply swallow it whole. To eat a squirrel, they use their sharp beak to systematically tear off bite-size pieces, starting with the most meaty hindquarters. The indigestible fur, bones, teeth, and claws are later regurgitated as compact pellets. It typically takes a screech-owl 1 to 2 days to fully consume an adult squirrel.
So through versatile hunting strategies and caching adaptations, the eastern screech-owl is well equipped to prey on gray squirrels of all ages.
How Often Do Screech Owls Eat Squirrels?
The frequency that screech-owls eat squirrels depends on the availability of squirrels in their habitat, season, competition from other predators, and hunger level of the owl.
In areas with lots of gray squirrels like urban parks and college campuses, squirrels may represent up to 60% of the screech-owl diet. Rural habitats with lower squirrel populations likely see less predation. Screech-owls are also more likely to target squirrels in fall and winter when less easily caught prey like insects, frogs, and songbirds are scarce.
In habitats with multiple squirrel predators like coyotes, foxes, bobcats and larger owls, screech-owls may lose out on some squirrels to the competition. Very well-fed screech-owls may pass up easier prey like mice and voles more often for harder-to-catch squirrels. Hungrier owls take more risks to grab whatever they can find.
On average, most screech-owls likely consume squirrels multiple times per month as a regular part of their varied diet. Particularly hungry, urban screech-owls may eat a squirrel every night or two when they are readily available. This predation pressure can help keep overly abundant squirrel populations in check.
Do Squirrels Have Any Defenses Against Screech Owls?
Gray squirrels have evolved several defenses to protect themselves against nocturnal predators like screech-owls:
- Camouflage – Their mottled gray, brown, and reddish fur blends into the tree canopy to avoid detection from above.
- Vocalizations – Squirrels make various squeaks and chatters that warn others of danger.
- Vigilance – Squirrels are always on high alert, constantly scanning in all directions.
- Rodent Teeth – Their sharp front teeth are used as weapons to bite attackers.
- Speed – Squirrels can quickly dodge by leaping sideways and diving down holes.
- Hiding – Squirrels hide in tree cavities and leaf nests during the day to stay out of sight.
- Agility – Their nimble movements and jumps make them difficult prey to pin down.
These defenses allow squirrels to avoid and deter many owl attacks. However screech-owls have their own counter-adaptations to still capture many unwary squirrels, especially younger ones. It’s a constant evolutionary arms race between predator and prey.
Do Squirrels Ever Act Aggressive Towards Screech Owls?
While squirrels certainly steer clear of screech-owls when possible, they may act surprisingly aggressive when threatened:
- Mobbing – Squirrels have been observed gathering together and rapidly circling and leaping around a roosting screech-owl while barking.
- Distraction Displays – “Kukking” and tail-flagging draws the owl’s attention away from nests and young.
- Harassment – Squirrels may try to bite, scratch, and repeatedly lunge at a hooded owl to persuade it to leave the area.
This mobbing behavior seems to be an attempted deterrent to make hunting harder for the owl and alert other squirrels in the area to the danger. It also gives nearby squirrel young a chance to take cover. While aggressive, squirrels rarely do serious harm to screech-owls, only chase them away. The hooded owl likely returns to hunt another night despite the harassment.
How Does Predation Affect Squirrel Population Size?
Despite plenty of screech-owl predation, squirrel populations remain quite stable overall. A few key factors prevent excessive depletion from owls and other predators:
- Squirrels have 2-3 litters per year averaging 2-4 young per litter, so reproduction is rapid.
- Only 25% of squirrels survive their first year, but survivors often live over 5 years.
- Habitat loss impacts squirrels more than predation.
- Squirrels adapt quickly to predation pressure with earlier breeding times.
- Numerous nest sites and food caches minimize predation risk.
So while screech-owls do kill many juvenile and older squirrels each year, enough crafty squirrels learn to avoid them and live on to reproduce the next generation. As long as there is ample forest habitat available, the eastern gray squirrel remains resilient against predation.
Excessive habitat fragmentation certainly makes squirrels more vulnerable to predation as they traverse open areas between islands of woods. But screech-owls alone cannot fully control squirrel numbers once they become overabundant in urban areas. Their predation simply slows population growth and shapes squirrel behavior to be more wary and secretive.
How Can You Tell If a Screech Owl Has Eaten a Squirrel?
Here are some signs that may indicate a screech-owl has successfully caught and eaten a squirrel:
Remains at a Plucking Post
Screech-owls often pluck and dismantle larger prey at a favorite secluded perch before taking pieces to the nest. Tufts of gray fur, severed squirrel tails, small bones and feet at the base of a tree are evidence an owl fed there.
Caching Sites
Look for squirrel remains like the skull, backbone, and ribs at known screech-owl caching spots in hollow trees, crevices, or dense thickets.
Regurgitated Fur and Bones
The compact, segmented owl pellets commonly produced after eating squirrels contain clearly identifiable squirrel bones, teeth, and fur. These are often found at roosting or nest sites.
Nocturnal Activity
Increased screech-owl calling and circling flight at dusk in an area with fewer visible squirrels may suggest they’ve caught and eaten some of the local squirrels.
So with close inspection, the signs of successful screech-owl predation on squirrels can be detected. This is one important way screech-owls help control rabbit, rodent, and small bird populations as part of nature’s balance.
Conclusion
In summary, screech-owls are frequent and effective predators of eastern gray squirrels throughout their range. They opportunistically prey on squirrels of all ages using stealth ambush techniques adapted for night hunting. While squirrels have defenses to avoid many attacks, screech-owls persist and eventually catch many unlucky individuals with skill and persistence. This predation pressure helps regulate squirrel populations wherever they coexist without endangering the long-term survival and abundance of this very prolific rodent. So the evidence clearly shows that yes, screech-owls readily feast on squirrels as an important part of their varied diet.