Barn owls are fascinating nocturnal birds of prey that are found worldwide. Their distinctive heart-shaped faces and light coloring make them easily recognizable. Barn owls are voracious predators that play an important role in controlling rodent and other small mammal populations. But what exactly do these mysterious owls eat?
Barn Owl Diet Overview
Barn owls are opportunistic hunters and will eat just about any small animal they can capture. Their main prey items include:
- Rodents – Rats, mice, voles, etc.
- Insects – Beetles, moths, crickets
- Small birds
- Bats
- Reptiles – Lizards, frogs, snakes
Rodents such as voles, mice, and rats make up over 50% of a barn owl’s diet. These prolific breeders can be agricultural pests, so barn owls provide important natural rodent control.
Insects like beetles, moths, crickets, and grasshoppers are the next most significant prey item. Barn owls often hunt over grasslands and fields where these insects congregate.
When available, barn owls will also prey on small birds like sparrows, swallows, and starlings. Bats are also occasionally eaten, especially species that roost in barns and other structures frequented by barn owls.
Reptiles and amphibians like lizards, frogs, and snakes represent a relatively small portion of a barn owl’s diet, but provide vital nutrients.
Now let’s explore the top 3 barn owl prey items in more detail…
#1 Rodents
Rodents such as mice, rats, voles, hamsters, and gerbils make up the majority of a barn owl’s diet. These prolific breeders can quickly become agricultural and household pests in the absence of predation. A single barn owl family can consume over 1,000 rodents per year, providing very effective natural pest control.
Various rodent species have adapted to live closely alongside humans, making them easy prey for barn owls in rural areas. The owls often hunt around farms, barns, and rural homes where rats and mice concentrate.
Rodents provide a nutritious, protein-rich food source for barn owls. A medium-sized rodent can sustain an owl for up to 3 days. The owls swallow their prey whole and later regurgitate indigestible parts like bones, fur, and teeth as pellets.
Voles are a favorite rodent prey species, as they are abundant in grasslands, meadows, and agricultural fields. Weighing only 1-2 ounces, a vole provides a perfect meal for a medium-sized barn owl. The owl’s incredible hearing allows it to detect and pinpoint voles scurrying through vegetation.
Advantages of Rodents as Prey
- Abundant and widespread
- Provide high nutritional value
- Lack defenses against predation
- Sustain an owl for multiple days
All of these attributes make rodents an ideal food source that barn owls have evolved to specialize in hunting.
#2 Insects
After rodents, insects comprise the next largest portion of a barn owl’s diet. Barn owls are well-adapted for hunting flying insects and will gorge on abundant species like beetles, moths, grasshoppers, and crickets.
Insects become especially important in the diet of nestling barn owls that require high protein content to sustain their rapid growth. The parents will hunt continuously to provide the chicks with a constant supply of insects.
Some common insect prey species include:
- Beetles – Scarab, June, and dung beetles
- Moths – Cutworm moths, gypsy moths
- Crickets – Field crickets, camel crickets
- Grasshoppers
- Caterpillars – Armyworms, cutworms
Barn owls are able to locate and capture flying insects by sight in total darkness. Their dish-shaped face collects sound waves, allowing them to hear the faintest rustling of insect wings. Hunting on continuous wing beats, barn owls will snatch up insects disturbed by their passage.
Certain insects like dung beetles and cutworm moth caterpillars can damage crops or become agricultural pests if left unchecked. Barn owls provide natural pest control by feeding on these insects.
Benefits of Insects for Barn Owls
- Often abundant and easy to catch
- Provide adequate nutrition for owl chicks
- Help control agricultural pest species
- Can be hunted in mid-flight using superb owl hearing
The abundance of insects like beetles and moths in many habitats makes them a reliable food source for barn owls.
#3 Small Birds
Though not as common as rodents or insects in their diet, barn owls occasionally prey on small bird species. Any small bird that roosts or nests within reach of a barn owl may get snatched up as a meal.
Some documented bird prey includes:
- Sparrows
- European starlings
- Swallows
- Wrens
- Finches
- Woodpeckers
- Martins
Barn owls haunt rafters and ledges in old barns, allowing them to surprise roosting birds. Nestlings and fledglings are especially vulnerable to barn owl predation.
The owls have also been known to ransack swallow and sparrow nests for an easy meal. Their stealthy silent flight allows them to approach and grab unsuspecting birds.
While avian prey provides needed calories, birds are less common in the diet than efficient rodent hunters due to some drawbacks.
Challenges of Hunting Birds
- Swift flight makes them harder to catch
- Lower calorie than rodents of the same size
- Owls may get mobbed by other defensive birds
- Less abundant than insects in many areas
These limitations prevent birds from becoming a primary food source for barn owls. But they still opportunistically take avian prey when the chance arises.
Other Prey
Beyond the main three prey groups, barn owls will eat any small animal they can overwhelm and swallow. Here are some other documented food items:
Bats
Bats that roost in old buildings and barns are perfect targets for prowling barn owls. Bats provide a nutritious source of meat and are easier for owls to catch than birds.
Reptiles and Amphibians
Lizards, snakes, frogs, salamanders, and newts often end up as barn owl prey. These ectotherms are abundant around wetlands and fields hunted by barn owls.
Arachnids
Spiders and scorpions are eaten occasionally. Mostly an incidental food source. Large tarantula species are sometimes deliberately eaten.
Fish
Mostly just a rare incidental prey item, but barn owls found near wetlands and rivers have been known to eat small fish on occasion.
Carrion
Barn owls are primarily hunters, but they will scavenge carrion and roadkill if extremely hungry.
Hunting and Foraging Strategy
Barn owls have a number of physical and behavioral adaptations that make them very successful hunters:
- Acute long-range hearing – Can pinpoint prey by sound alone
- Excellent low light vision – Can see vertebrate prey up to 100 feet away on darkest nights
- Soft feathers – Allows silent stealth flight to surprise prey
- Heart-shaped facial disc – Funnels sound waves to ears
- Sharp talons – Quickly dispatch and carry prey
- Agile flight – Makes tight turns and dives in pursuit of prey
Barn owls mainly hunt through sustained quartering flights over prey-rich habitat. Their flying style disturbs and flushes hidden rodents and insects into movement where they can be detected and captured.
Ideal hunting zones include:
- Grasslands
- Meadows
- Farmland
- Wetlands
- Old barns and abandoned buildings
Barn owls can hunt on continuous wing beats for hours without tiring. They also use favorite perches to watch and listen for prey movement.
Captured prey is quickly swallowed whole and carried back to the nest or a favored roost site to be torn apart by the owl’s strong beak and talons.
Digestion and Pellet Regurgitation
Like all raptors, barn owls have a very efficient digestive system to make the most of their prey. The acidic stomach digests all the flesh, organs, and tissues of eaten prey.
But barn owls cannot digest bones, fur, feathers, claws, beetle shells, and other hard parts. Up to 10 hours after eating, they cough up a pellet containing all these indigestible materials.
Examining these barn owl pellets provides great insight into an owl’s diet and the small critters sharing its habitat. Owl pellets are collected by researchers to study owl ecology and their role as keystone predators.
Diet Variations
The specific prey composition in a barn owl’s diet can vary based on:
- Geographic location – climate and available prey species
- Habitat – grasslands vs. wetlands
- Prey abundance – fluctuates seasonally
- Age of owl – nestlings need more protein
But invariably rodents are the primary food source. One study in California found that ground squirrels, pocket gophers, deer mice, and voles made up over 90% of prey remains in barn owl pellets and nests.
Barn owls are amazingly adaptable and can thrive on whatever small prey is abundant in their habitat, switching prey species as availability fluctuates.
Barn Owl Predators
While apex predators to small mammals and birds, barn owls do fall prey to larger predators on occasion. Main barn owl predators include:
- Great horned owls
- Red-tailed hawks
- Coyotes
- Foxes
- Bobcats
- Feral cats
These predators may pick off a barn owl sleeping in a cavity roost site or ambush one in flight.
Vehicles also account for many barn owl mortalities, as the low-flying owls are struck while hunting roads.
Predation is most common in owls during their first year of life. Only an estimated 20% survive to adulthood. But those that make it can live for 10-15 years in the wild.
Importance to the Ecosystem
Barn owls fill an important ecological niche as predators of small vertebrates like rodents and bats. In many ecosystems they are considered a keystone species due to their strong regulatory effects on prey populations.
Some key ecosystem services barn owls provide through their dietary habits include:
- Suppress rodent pest populations – A family of barn owls can consume thousands of agricultural pest rodents per year.
- Reduce disease transmission – Fewer rodents results in decreased spread of rodent-borne illnesses.
- Nutrient dispersal – Owls deposit nutrients from prey remains across the landscape via pellets.
- Prey population regulation – Predation reduces prey spikes and disruptive fluctuations.
Barn owls help keep rodent numbers in check without the use of chemical pesticides. This makes them highly valuable to farmers, ranchers, and all landowners troubled by destructive rodent pests.
Many regions have seen rodent population explosions and resulting agricultural damage when barn owl populations declined from habitat loss or persecution.
Threats and Conservation Status
Barn owl global populations are generally stable with an IUCN Red List conservation status of “Least Concern.” But locally they have suffered declines and even disappeared from some areas.
Threats that have impacted barn owls include:
- Habitat loss – Fewer old barns and loss of natural grasslands
- Vehicle collisions – Owls foraging along roadsides get hit
- Rodenticide poisoning – Prey ingest poison which bioaccumulates up the food chain
- Climate change – Extreme weather impacts reproduction and prey abundance
- Nesting and roosting disturbance
Various conservation initiatives across the owl’s range aim to reverse declines and restore populations. Providing nest boxes, limiting rodenticide use, and protecting grassland habitat can all benefit local barn owl populations.
Conclusion
Barn owls are remarkable nocturnal predators that play an outsized role in controlling rodent populations. Despite their spooky reputation, these owls provide tremendous agricultural and ecological benefits through their voracious appetite for small mammals.
Understanding the barn owl diet provides key insights into their natural history. We see how their hearing, vision, and flight abilities make them supreme nighttime hunters. Examining their prey preferences and foraging behavior reveals their intricate connections to the surrounding ecosystem.
While insects and birds supplement their diet, the barn owl is truly a rodent-eating specialist. Their ecological niche depends on this primarily rodent-based food web. Efforts to reduce habitat loss and reverse population declines will ensure barn owls continue controlling pests and enriching ecosystems with their fascinating natural history for generations to come.