The nocturnal raptor Barn owl (Tyto alba) demonstrates unique attributes, both morphological and biological. It has developed several unique ecological and behavioral characteristics. It is a raptor that hunts its prey at night and feeds almost exclusively on small mammals, throughout the geographical range of its distribution.

Name etymology 

The scientific Latin name of the nocturnal raptor Tyto “Tyto Alba”, derives from the ancient Greek word "Tyto", which was attributed to this species since antiquity, and the Latin word "alba", which means white, because the lower part of the raptor’s body, its chest, the lower part of the wings and its legs are white. 

Body measurements 

Barn owl’s height ranges from 32cm to 40cm, and its wingspan from 85cm up to 1m. The weight of adult individuals varies from 400gr to 600gr.  

Barn owl flying over agricultural crops demonstrates its wingspan and long legs during foraging

The fact that both Barn owl’s eyes are positioned at the front of its head equips the species with a binocular vision of wide range

Adaptations for prey capture: Vision

The Barn owl has large eyes and, unlike many other bird species, they are positioned at the front of its head and not on the sides. This equips Barn owls with “binocular vision" and enables the species to estimate distances accurately when hunting. Also, the vision of the species is adapted to low light and is sensitive to any small movement. The dark eye color of the Barn owl allows it to function visually during the day 

Watch the videos:

TYTO's silent flight
TYTO's flight mechanism

Adaptations for prey capture: claws

Barn owl claws are specially adapted, they are lengthy, sharp, and hard. Their underneath part is durable with strong skin-scales, so that it can kill the prey immediately and with the first catch. 

Barn owl has sharp and long nails for catching and killing prey

Barn owl pouncing before catching its prey reveals long-leg length for prey capture

Adaptations for prey capture: leg height

The Barn owl has lengthy legs. This physically evolving adaptation enables the species, to immerse its feet in high vegetation, when hunting and attacking, and thus being able to reach the base of the ground through high vegetation to capture its prey.

Adaptations for prey capture: Acoustic location

One of the most striking adaptations of the Barn owl is that its acoustic chambers are not positioned at the same height on the two sides of its facial disk. When the prey's sound arrives, it creates a "three-dimensional" representation of the prey’s exact location within Barn owl’s brain. Barn owl hearing is also specially adapted to the high frequencies emitted by small mammals, which are its main prey.

It has been proved that Barn owl’s hearing is the most sensitive of all other animal species. In addition, the species’ "facial disk" is shaped so that both the inclinations of the semicircles of the face and the morphology of the face feathers accurately collect and direct the sound inside the auditory chambers.

Barn owl right acoustic chamber is positioned lower than the left for enhanced acoustic prey detection

Barn owl feather detail, photo by Kay Schultz

Adaptations for prey capture: feathers and silent flight

Barn owl has the quietest flight compared to all other bird species. It has an inversely proportional relationship between the large size of its wings (opening up to 1m or even 110cm) in relation to small body weight (400gr to 600gr). This means that it can fly very slowly, and take advantage of even the smallest air currents. Barn owl’s slow and steady flight allows it to locate its prey. In addition, the Barn owl has unique adaptations to its feathers and wings which are covered with a thin fiber structure that traps air inside the surface of the wing. This ensures a smooth airflow in the wings and the ability to fly and maneuver at low speeds.

Adaptations for prey capture: Preference for small mammals 

Barn owl, throughout its global distribution, feeds almost exclusively (95% -99%) on small mammals: mice, rodents, and rats. In fact, it demonstrates two important trends: It is a specialized predator: from all the existing food resources in an area where it lives, it will capture and consume only small mammals, and secondly it is a generalist predator within the group of small mammals, since it will focus on those species which are the most numerous. That proves that it is always the best natural regulator of harmful small mammals that demonstrate population outbreaks, as it focuses primarily on those with high population densities.

A Barn owl individual can hunt an average of 2,000 to 4,000, and even 5,000 small mammals over the course of a year.

Barn owl holds its prey in its beak - a mouse just captured

Barn owl holds its prey in its beak - a mouse just captured

Reproduction adaptations: keeps track of rodent population outbreaks

Barn owl reproduction adapts to the rhythm of rodent population outbreaks. In specific, when the species realizes which periods small mammal populations will be low, it may choose not to reproduce at all, or to reproduce having a limited number of eggs.

On the contrary, during periods that the species realizes there will be higher small mammal and harmful rodent populations, it will often breed twice in a period from March to October and lay a larger number of eggs than usual. As is often observed in Thessaly, we have observed broods with 8, 9, or 10 Barn owl chicks in the artificial nest boxes we provide.

Barn owl incubates a litter with a large number of nine eggs in Nikaia, Larissa

Feeding adaptations: pellets excretion 

The Barn owl usually swallows its prey whole. In case a rodent species is very large, Barn owl may cut it into two pieces in order to eat it. However, it cannot digest the hairs and bones, so in another part of their stomach, Barn owls gather the hairs and bones of the captured small mammals which are formed in oval-sphericall black pellets. It excretes these pellets from its mouth at an average rate of two per night. Within Barn owl nests and perching sites which are systematically used by Barn owls, the concentration of pellets is very high, and this is an indirect indicator of the presence of Barn owls.

From the systematic seasonal and spatial analysis of these pellets, useful conclusions, deep insights, and predictive models emerge defining the distribution and population changes of small mammal species in the rural countryside.

Close-up photo of a pellet that a Barn owl has excreted through its mouth. Parts of small mammal bones are visible

Close-up photo of a pellet that a Barn owl has excreted through its mouth. Parts of small mammal bones are visible

Set your categories menu in Header builder -> Mobile -> Mobile menu element -> Show/Hide -> Choose menu
Shopping cart
We use cookies to improve your experience on our website. By browsing this website, you agree to our use of cookies.
Start typing to see posts you are looking for.