The funny looking bird with big eyes that many people are curious about is likely the tawny owl. Tawny owls are medium-sized owls that are found throughout much of Europe and parts of Asia. They get their name from their tawny brown feathers that help them blend into tree bark where they roost during the day. Tawny owls have large, round eyes that can appear quite striking, especially against their feathers.
What makes the tawny owl’s eyes look so big?
There are a few reasons why tawny owls have such prominent, large-looking eyes:
- Their eyes are positioned on the front of their faces, allowing for binocular vision.
- They have elongated facial disks around their eyes that help direct sounds toward their ears.
- Their eyes are disproportionately large compared to their head size.
- Their feathers around the eyes are light-colored, creating contrast.
Like other owls, tawny owls have evolved excellent low-light vision and highly sensitive eyesight. Their large eyes allow more light to enter the eye, improving their ability to see at night. They also have a high density of rod cells in their retinas for better night vision.
What color are a tawny owl’s eyes?
Tawny owls typically have dark brown or black colored eyes. The brownish-black hue helps reduce glare while hunting at night. When light catches their eyes, a subtle orange or reddish tinge may be visible around the pupil, which is why they are sometimes described as having dark orange eyes.
Why do they have such big eyes compared to other birds?
All owls have large, forward-facing eyes compared to many other birds, but tawny owls are particularly known for their striking eyes.
There are a few reasons owls evolved to have bigger eyes than other birds:
- Owls are primarily nocturnal hunters, so they rely heavily on vision in low-light conditions. Larger eyes allow more light to enter.
- Their eyes are fixed in place by bony structures in their skulls, so they cannot move their eyes around. Larger eyes allow them to have a wider field of view without moving their eyes.
- Many owls, like the tawny owl, have specialized asymmetrical ears located under facial disks around their eyes. The disks help direct sound to their ears, so the larger eye size accommodates the facial disk structure.
- Larger eyes also allow for increased visual acuity to spot and target prey in low light.
The tawny owl in particular has eyes that are exceptionally big for its head and body size compared to other owl species. This suggests strong adaptation for maximizing visual capabilities in its forest habitat.
What is the tawny owl’s habitat and distribution?
Tawny owls are found across much of Europe and parts of western Asia. Their breeding range extends from Great Britain east through temperate Europe and Russia to Iran and western Siberia. Northern populations are migratory while southern ones are often year-round residents.
They inhabit mixed and deciduous forests across much of their range. Mature woodland with old trees that provide cavities for nesting and roosting are preferred. Parklands, wooded swamps, and orchards also provide good habitat. They generally avoid open habitats like grasslands or marshland.
In parts of their range, tawny owls have also adapted to live in more urban environments and can even be found in city parks, cemeteries, and other green spaces.
What do tawny owls eat?
Tawny owls are opportunistic predators and eat a variety of prey depending on what is locally abundant:
- Small rodents – Voles, mice, rats, squirrels
- Birds – Sparrows, thrushes, blackbirds, woodpeckers
- Invertebrates – Large beetles, moths, crickets, earthworms
- Amphibians and reptiles – Frogs, toads, lizards, snakes
- Fish
- Insects
- Bats
They hunt primarily by perching and waiting to ambush prey from an elevated vantage point. With their excellent low-light vision, they can detect even small movements on the forest floor from up to 100 feet away. Tawny owls will also hover-hunt and even hunt on the ground at times.
How do tawny owls hunt?
Tawny owls are nocturnal hunters and use a few key methods to catch prey:
- Perch hunting – Their preferred method. Tawny owls will wait patiently on an elevated perch watching and listening for prey movement below. Once spotted, they will swoop down silently and use their talons to catch prey.
- Hover hunting – They will sometimes hover-hunt by flying low over an area and using their exceptional hearing to pinpoint rustling prey in vegetation.
- Ground hunting – Less common, but tawny owls will hunt on the ground if necessary, walking or running to chase down prey.
- Hawking – Occasionally they will catch prey in midair by flying from a perch to intercept insects, bats, or birds.
Their flight is nearly silent thanks to special soft, fringed edges on their primary wing feathers. This allows them to swoop down on prey undetected.
How do tawny owls reproduce?
Tawny owls nest in cavities in tree trunks or old stick nests built by other birds. They do not build their own nests. Mating occurs in late winter through early spring, with females laying eggs in March or April. The female will lay 2-5 eggs over a few days and incubate them for about 30 days before they hatch.
Once hatched, the male will initially help feed the chicks by passing food to the female at the nest. After about 2 weeks, the female leaves the nest to join the male in hunting. For about 4 weeks, both parents feed the hungry chicks which leave the nest at around 4-5 weeks old but remain dependent on the parents for another 1-2 months.
What sounds does the tawny owl make?
Tawny owls have a variety of vocalizations used for communication. Some key sounds include:
- Territorial hoot – Their most recognizable call, the male’s territorial hoot is a drawn out “hoo-hoo-hoo-hu” sound.
- Female hoot – Females make a higher pitched, harsher hoot sound than males.
- Juvenile begging call – Young tawny owls make a repetitive hissing or snoring sound when begging for food.
- Alarm call – When alarmed, tawny owls will make a high-pitched screeching sound.
- Male and female duetting – Paired males and females will call back and forth to each other with hoots.
Why are tawny owls important ecologically?
As nocturnal predators of small mammals, birds and insects, tawny owls play an important role in balancing ecosystems. Some key ecological functions they provide are:
- Regulating rodent and small mammal populations. This helps limit damage to crops and vegetation caused by high populations of prey species.
- Scavenging on carrion and diseased animals helps clean up the environment.
- Preying on insects can reduce spread of insect-borne disease and agricultural pests.
- Dispersing seeds from fruit when prey is scarce and scattering feathers and remains which fertilize the soil.
Declines in tawny owl populations from threats like habitat loss and rodenticide poisoning can disturb the ecological balance and allow prey to increase unnaturally. Maintaining healthy owl numbers provides natural checks and balances.
How many subspecies of tawny owl exist?
There are considered to be 9 recognized subspecies of tawny owl across Eurasia:
- Strix aluco aluco – Northern and central Europe
- Strix aluco sylvatica – Iberian Peninsula and northwestern Africa
- Strix aluco guttata – Sicily and Malta
- Strix aluco wilkonskii – Cyprus
- Strix aluco caucasica – Caucasus region
- Strix aluco lapponica – Scandinavia through Siberia
- Strix aluco leucopsis – Turkestan
- Strix aluco plumipes – Tibet and Himalayas
- Strix aluco ma – Siberia and northeastern China
While some variations in size, color, and voice exist between subspecies, their behaviors and ecology remain largely the same. No subspecies are currently at risk.
How has the tawny owl population changed over time?
Tawny owl populations are generally stable or increasing in Europe, though they have declined in parts of western Europe. In the UK, populations doubled during the 20th century as mature woodland expanded. But since the 1990s, declines up to 50% have occurred in Britain possibly due to agricultural intensification reducing prey availability.
Time Period | Population Trend |
---|---|
1900s – 1990s | Increasing in UK and stable in Europe |
1990s – now | Declining in UK, stable in Europe |
In their Asian range, less data exists but tawny owls appear to be declining in western parts of Russia while remaining widespread further east in Siberia. Loss of nesting sites and unintended poisoning from pest control continue to pose risks to local populations.
Why are tawny owls declining in some areas?
While still common in much of Europe, tawny owl numbers have dropped in parts of their western range. Some of the main threats believed to be causing declines include:
- Habitat loss – Loss of mature, natural woodlands reduces habitat and nesting sites.
- Agricultural intensification – Reduces prey populations and food availability.
- Road collisions – Owls hunting near roads are at risk of being hit by vehicles.
- Rodenticide poisoning – Preying on poisoned rodents exposes owls to toxic chemicals.
- Climate change – Threatens prey populations and disrupts timing of reproduction.
Maintaining large intact forests and limiting use of chemicals and rodent poisons in agricultural areas can help halt declines from these threats.
Fun facts about tawny owls
- Tawny owls don’t actually hoot “who”. The “who” sound is made by a different owl called the eagle owl.
- The Harry Potter books describe Harry’s owl Hedwig as a tawny owl. Tawny owls were likely inspiration for many depictions of owls in literature.
- While capable of capturing prey up to the size of rabbits, tawny owls most often take small rodents weighing only 1-3 ounces.
- Tawny owl feathers have specialized soft edges allowing near silent flight. They can swoop down on prey without making a sound.
- Tawny owls rely so heavily on their hearing that they have been known to hunt mice successfully while blindfolded in experiments.
- The tawny owl’s Latin name Strix aluco may be derived from Greek word meaning “owl” and the hooting sound they make.
- Tawny owl pairs often use the same nesting site for many years, with some records of sites used for over 20 years.
- Tawny owls are one of the only owl species found in urban areas, sometimes even nesting in barn lofts or dense parks.
- The tawny owl is considered the most common owl across much of Europe.
Conclusion
With its prominent dark eyes, rounded head, and mottled brown plumage, the tawny owl has an unmistakable appearance fitting of its common name. As a highly adaptable forest owl, the tawny owl fills an important ecological role as an apex nocturnal predator balancing populations of small mammals and birds. While still widespread, threats from habitat loss, pesticides, and vehicle collisions highlight the need for continued conservation efforts for this iconic woodland owl.