Barn Owl

Most widespread among all species of owls, the Barn Owl is an easily recognizable bird with an adorable heart-shaped face. Due to their eerily white color, they are often considered ominous, but with that benign look, you may wonder how this bird could do anything evil.

With their distinctive undulating flight pattern and powerful talons, they are silent predators of the night world, grabbing prey from open vegetation like grasslands and agricultural fields.

Subspecies

There are at least three recognized lineages of the Barn Owl.

• The Western Barn Owl
• The Eastern Barn Owl
• The American Barn Owl

According to the International Ornithologists’ Union, the Western Barn Owls have been branched into around ten subspecies. Similarly, in the Handbook of Birds of the World Volume 5: Barn-owls to Hummingbirds, the Eastern and American Barn owl are divided into seven and ten subspecies, respectively.

Description

Length: Body: Male – 32 to 38 cm (12.5 inches to 14.9 inches) Female – 34 to 40 cm (13.3 inches to 15.7 inches)  Wingspan: 107 to 110 cm (42.1 inches to 43.3 inches)

Weight: Male – 470 gm (1 lb) Female – 570 gm (1.2 lbs)

Body and Coloration:

This species has a medium-sized spotted body that is golden-brown on the dorsal side and grayish-white on the ventral side. On average, females tend to have more spots on the underside and are reddish than males.

The face is heart-shaped and bordered with a striking ring of brown feathers. Their round wings, feathered legs, and short tails also give them a unique appearance.

Distribution

Barn Owls are found in almost all continents except Antarctica. In the Americas, they extend from British Columbia, North Dakota, and Michigan to South America, while in Europe, they range from Spain to Sweden, extending to Russia in the east. They are also abundant in Asia, Africa, and Australia. 

Habitat

They usually reside at low elevations in open habitats like grasslands, deserts, marshes, and agricultural fields. Nesting and roosting occur in hollow trees, cliffs, and artificial structures such as barn lofts, hay stacks, and church steeples.

Diet

Essentially carnivores, these owls feed primarily on rodents and small mammals like mice, muskrats, bats, rabbits, and hares. In North America and Europe, voles predominate their diet, while shrews are the second most common food choice. Depending on availability, they also feed on lizards, amphibians, fish, and insects.

If the owls accidentally feed on infected prey, they might acquire gut parasites fluke, tapeworms and spiny-headed worms. 

Behavior

1. As nocturnal hunters, they fly low over open habitats at night and keenly notice their prey from a distance. After spotting a suitable target, they quickly dive and grab it along. Barn owls ingest their prey whole and cough up pellets twice daily instead of eliminating waste the standard way. 
2. Unlike most hooting owls, they communicate with each other using raspy hissing and shrieking sounds. The young have a snoring food call, while the owlets twitter when expressing discomfort or quarreling with their nest mates. In adults, the ‘distress call’ is a series of prolonged screams followed by explosive yells at the predator.
3. When encountering an intruder, they squint their eyes and display the dorsal surface of their wings, moving their head back and forth. This ‘threat display’ is often accompanied by hissing and snapping of beaks. If the intruder persists, the owls fall on their back and repeatedly strike with their feet.

Lifespan

In the wild, they typically have a lifespan of about 2 to 5 years, with many surviving only one breeding season. There are, however, reports of the species living as long as 18 years or more in Scotland (Marti, 1992). When in captivity, they can survive up to 15 to 20 years.

Reproduction and Life Cycle

Barn Owls are primarily monogamous, with the pairs remaining together as long as they live. Depending on the food supply, they can breed any time of the year. Most individuals start breeding when about a year old and raise one brood yearly. Due to their short lifespan, most barn owls can only breed once or twice.  

Courtship begins with characteristic male display flights, followed by advertising calls to the females. These calls are the most prominent adult vocalizations, characterized by long, gargling screams. The males then screech and chase their mates, hovering with their feet dangling in front of the perched females for a few seconds. This gesture is known as the ‘moth flight.’

Both the sexes crouch in front of each other, seeking the other to make the first move. The male mounts the female and grasps her neck, balancing with spread wings. Copulation continues through the phases of incubation and rearing, though with a constant decrease in frequency.

The female usually lines a new nest with shredded pellets to protect her baby, but they often reuse old nests. It can lay up to 18 chalky-white, elliptical eggs with a frequency of one egg every two to three days. It incubates the eggs for about a month, and the mother leads the chicks 25 days after hatching.

The female does most brooding, while the males procure food from outside. The mother initially feeds her young, tearing their food into pieces while also sanitizing the nest by eating away the feces of the young. About two months after hatching, the chicks learn to take their first flight and become independent 3 to 5 weeks later.

Predators

They are preyed upon by large opossums, raccoons, and other carnivorous mammals. Golden eagles, red kites, falcons, vultures, hawks, and other species of owls like the tawny, eagle, and great horned owls also attack these birds. In the Americas, the Eurasian eagle owl is a significant predator. 

Adaptations

1. Their heart-shaped facial discs help funnel sound waves into their ears, alarming them of rustling leaves and the movement of tiny creatures on the ground. The ears are placed asymmetrically, thus improving sound perception from a distance. 
2. They have notably long legs, toes, and talons for catching prey from the base of vegetation. 
3. The soft ‘down feathers’ on the wings and legs help them swoop down silently and grab the prey without giving away its arrival. The forewing feathers have a row of tiny hooks that help to nullify the sound of air hitting their leading edge.
4. They have highly sensitive eyes that can adjust their perception of depth at night.

Conservation Status

Though the Barn Owl belongs to the IUCN ‘Least Concern’ category, the constant threat of population decline remains a concern. In the UK, their numbers have reportedly declined since the 1900s due to extensive agricultural practices, sprawling development in the countryside, increased use of the pesticide DDT, and road deaths.

Considering their beneficial role in the food web, focusing on their conservation has become imperative. Building suitably designed artificial nesting sites and preserving the existing ones can save them from being endangered in the near future.