Barn owls are nocturnal birds of prey, which means they are most active at night. Their large eyes and excellent hearing allow them to hunt efficiently in darkness. During the day, barn owls rest in dark, secluded places to avoid predators and disturbance. However, they are sometimes observed outside their roosts during daylight hours. This article explores what barn owls typically do during the hours of sunlight.
Sleep and Roost in Hidden Locations
Barn owls spend most of the daylight hours sleeping in their roosts. A roost is a place where the owls rest and sleep during the day. Ideal roosting spots are dark, quiet, and concealed from predators and human activity. Common roosting locations include:
– Abandoned buildings and barns (which gives the barn owl its name)
– Hollows and cavities in trees
– Caves and crevices in cliffs and rocks
– Nest boxes put up specifically for barn owls
– Dense thickets of vegetation
The darkness of these concealed spaces allows the light-sensitive eyes of the owls to rest. Barn owls tend to reuse the same roosting spots as long as they remain undisturbed. Some roost sites may be used by both breeding and non-breeding owls.
Why Barn Owls Roost During the Day
Barn owls roost in hidden sites during the day for several important reasons:
– Avoid predators – Roosting in sheltered spots helps camouflage barn owls from daytime predators like hawks, eagles and falcons. If caught in the open during daylight, barn owls are vulnerable due to their primarily nocturnal nature.
– Rest their eyes – The eyes of barn owls are specially adapted to function in low-light conditions. Bright sunlight can damage their sensitive retina and affects their ability to see properly. Dark roosts allow their eyes to rest after a night of hunting.
– Conserve energy – By sleeping through the daytime when they are less active, barn owls conserve energy for hunting at night.
– Regulate body temperature – Barn owls can more easily maintain their body temperature in enclosed cavities that provide insulation and shelter from the elements.
– Avoid disturbance – Secluded roosts minimize disturbances from noise, human activity, and other animals that could stress the owls and disrupt their rest.
Roosting Behavior and Habits
When in their roosts, barn owls exhibit the following behaviors and habits:
– Settle into a resting posture by standing on their tarsi (lower legs) with body flattened and wings folded. May also squat or sit on their breasts.
– Often roost in pairs or small groups, sometimes in direct body contact with other owls. May roost singly especially when nesting.
– Usually roost on sheltered perches like rafters and ledges, but occasionally directly on floors or the ground.
– Remain alert and awake for some time before settling down to sleep.
– May hiss, snap bills or sway if disturbed. Usually flee the roost if disturbance continues.
– Typically change roosting positions every 1-3 days, rotating among suitable sites within their home range.
– May line the roost floor with cast pellets, prey remains and excrement over time.
– Most active in roosts right after emerging at dusk, and before departing at dawn.
Hunt and Forage Opportunistically
Though primarily nocturnal hunters, barn owls may occasionally forage during the day if severely hungry. However, their daylight hunting is limited by the constraints of their sensitive vision. Barn owls may opportunistically hunt in low-light daytime conditions such as:
Overcast or stormy weather – Heavily overcast skies offer dim lighting suitable for the owls to hunt. Rainy, snowy or foggy conditions also provide adequate darkness.
Early morning and dusk – Crepuscular periods around dawn and dusk provide sufficient darkness for barn owls to see and hunt. They often begin foraging before night fully sets in.
Inside barns and outbuildings – The shaded interior of structures can allow successful daytime hunting. This is especially true of old, cavernous barns with many hiding perches.
Tree cavities and dense foliage – Dense vegetation and hollow tree trunks create dark spaces for barn owls to seek hidden prey during daylight.
Barn owls may also opportunistically eat prey that happens across their path, such as:
– Cached food stores in or near their roosts
– Rodents at owl nest sites
– Carrion from dead animals
– Prey remains left by other predators
By making use of such readily available food sources, barn owls can offset some of the challenges of daytime hunting. This allows them to conserve energy for peak nocturnal activity.
Interact with Mates and Offspring
The breeding season is one time when barn owls may spend more time active outside their roosts during daylight. Barn owl courtship and nesting usually spans March/April to September. Breeding behaviors like courtship flights, mating, and provisioning nestlings often begin before sunset and continue after sunrise.
Courtship and Mating
Male barn owls establish nesting territories beginning in late winter. Throughout courtship they advertise territorial ownership using raspy, drawn-out screech calls that act like auditory mating displays. Both sexes engage in courtship flights together at dawn and dusk, performing acrobatic aerial maneuvers over the nest site.
Daytime copulations occur more frequently as pairs cement their bonds. The peak of mating happens in April/May, but can continue through the summer before the female begins egg laying.
Provisioning Nestlings
For the 50-70 days after hatching, both parents hunt intensely to provide enough food for their rapidly growing brood. They may even hunt opportunistically during the day to ensure adequate provisioning. The male typically roosts in the nest hollow or a nearby perch, ready to receive deliveries of prey brought by the female throughout the day.
Barn owl chicks are very noisy, constantly vocalizing hunger with raspy calls. Both parents communicate with nestlings through vocalizations and food displays to synchronize provisioning. Parents may remove and consume rodent waste to keep the nest clean.
Perform Nest Site and Roost Maintenance
Barn owls spend more time at and around nests and roosts during breeding season to perform vital site maintenance activities:
Nest Preparation
Though they don’t build elaborate nests, barn owls do need to prepare and clean nesting cavities. This is done primarily by the female before egg-laying:
– Remove debris and old nesting material from previous years
– Line the nest floor with small debris and pellets
– Regularly remove rodent waste and pellets from nest hollow
The male may provide some assistance, but the female takes the lead preparing the nest.
Roost Maintenance
Barn owls often have a network of alternative roosts within their home range. Both sexes perform maintenance at roost sites:
– Remove accumulated waste, pellets and prey debris
– Air out and dry damp roosts
– Make minor repairs to access holes
Well-maintained roosts are essential for healthy barn owls throughout the year.
Defend Nest Sites from Competitors
The peak breeding season also makes barn owls more aggressive in defending their nest territories from intruders and competitors. Barn owls are not social nesters – they do not tolerate other pairs nesting nearby. To deter competitors, barn owls may:
– Give alarm calls and warning hisses at roost entrances
– Make rapid fly-bys at intruders
– Perform distraction displays to draw predators and scavengers away from the nest
Both sexes defend the nest, but males take the lead role. They patrol the nest territory both at night and opportunistically during the day looking for trespassers. Aggressive defense ensures access to sufficient food resources for their mate and offspring.
Transition Between Roosts
Barn owls frequently change roosting spots within their home range. An individual may use 20 different nesting or roosting cavities over a breeding season. When switching sites during the daytime, they exhibit the following behaviors:
– Depart current roost site 30-60 minutes after sunset, often later if very recently fed
– Make one or more recon flights circling potential new roosts
– Enter and briefly inspect interior of new roost before settling in
– May vocalize upon entering new roost to advertise site claim
– Often roost with mate if pair-bonded, but not always
Roost transitions are usually completed swiftly just after emerging at dusk. This minimizes time spent conspicuously flying in the open. Regular roost rotations likely help avoid parasites and reduce predation. The increased activity offers important exercise as well.
Sunbathe Anting and Preening
Though minimal, barn owls do spend some non-hunting time outside roosts on sunny days. Sunbathing and preening are important daylight activities:
Sunbathing
Perching or lying in the open sun serves multiple functions for barn owls:
– Helps control bacteria and fungi that can degrade feather quality
– Discourages ectoparasites like bird lice that cannot survive in UV light
– Provides opportunities to realign and clean feathers
– Allows vitamin D synthesis for bone health
Barn owls sunbathe most frequently in the early morning once temperatures warm. Typically performed at secluded perches or nest entrances facing the rising sun.
Anting
Anting describes the practice of smearing ants over the body while sunbathing. The formic acid produced by ants helps to:
– Control parasites and microbes
– Supplement preen oil distribution for waterproofing feathers
– Freshen plumage and improve feather flexibility
Barn owls mainly ant in late summer-early fall when ant availability peaks. It supplements their regular preening maintenance.
Preening
Using their sharp talons and beak, barn owls meticulously preen and realign feathers for maximum aerodynamic efficiency. Key benefits include:
– Redistribute protective oils from the uropygial gland
– Remove dirt, parasites, old feather parts, and animal fur
– Align feather barbicels for smooth laminar airflow
Thorough preening takes considerable time and effort. Barn owls preen after waking and throughout nightly roosting periods. Sunbathing provides ideal warm conditions for intensive preening. Periodic daytime preening is essential for healthy plumage.
Coping with Disturbance and Roost Loss
Though barn owls prefer isolated, undisturbed roost sites, they may be forced to use marginal roosts closer to human activity. Logging, agriculture, and construction can eliminate old roost trees and structures. Habitat loss pushes barn owls to adapt. Disturbed owls exhibit the following behaviors:
Use Less Suitable Roosts
When optimal cavities are unavailable, barn owls may roost in marginal sites such as:
– Niches in occupied buildings and sheds
– Trees and caves offering inadequate shelter
– Dense shrubs or vines for makeshift cover
– Open rafters and beams in barns and outbuildings
– Abandoned nests of other bird species
These inferior roosts leave owls more exposed to weather and predators, causing greater stress.
Roost in Close Proximity to Humans
Displaced owls often end up roosting closer to human activity including:
– Barns and stables with livestock and people
– Porches, garages, and covered patios on houses
– Buildings with heavy foot traffic and occupancy
– Loud sites near roads, farms, or industrial areas
The noise, artificial light and disruption make it harder for owls to rest. They are more prone to abandoning roosts.
Shift to More Nocturnal Activity
When roosting close to human activity, barn owls try to remain in sheltered spots during daylight to avoid detection and disturbances. Their activity shifts to be more skewed toward nocturnal-only foraging and roosting transitions under cover of darkness. Loss of suitable habitat can seriously impact barn owl health and productivity.
Conclusion
Though primarily nocturnal, barn owls do exhibit interesting and important activities during daylight hours. Choice of sheltered, secluded roost sites and sunlight avoidance characterize most barn owl daytime behavior. But reproductive activities, maintenance needs, foraging opportunities, and habitat loss also affect daytime behavior patterns. Further research is still needed to fully understand how barn owls balance nighttime and daytime activity in response to changing environmental pressures. Their ability to adjust circadian rhythms and habitat use will determine barn owl survival in the future.
