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Strigidae

life science Maturity 11-13 Next article →

The family Strigidae contains the true owls, often called typical owls.

Tawnyowl03
Tawnyowl03

This massive group includes 230 living or recently extinct species. They are spread across the entire world, appearing on every continent except Antarctica. Within this family, sizes vary drastically. The tiny elf owl is only a hundredth the size of the largest species. These giants include the Eurasian eagle-owl and Blakiston's fish owl.

Bubo blakistoni
Bubo blakistoni

Despite these size differences, most owls share a very similar body plan. They typically possess large heads, short tails, and cryptic plumage for camouflage. Most species are arboreal, meaning they live in trees, though the burrowing owl is an exception.

Owls are masters of silent flight, which allows them to hunt prey without being detected.

Strix nebulosa plumage
Strix nebulosa plumage

This ability comes from three specific physical adaptations in their wings. First, a comb of stiff feathers sits on the leading edge of the wing. Second, the trailing edge contains a flexible fringe of feathers. Third, the tops of the wings are covered in downy material. This downy texture is similar to a soft carpet. Together, these features create significant aerodynamic noise reductions during takeoff, flapping, and gliding.

To find prey, owls rely on highly sensitive hearing and massive eyes. Their ears are asymmetrical, meaning they are positioned differently on each side of the head. This asymmetry helps the owl localize sounds in multiple directions. The feathers of the facial disc are arranged specifically to increase the amount of sound delivered to the ears. If a mouse squeaks, the owl computes the timing of the sound. If the sound reaches the left ear first, the owl knows the prey is to its left. The brain then directs the head to face the target.

One of the most remarkable traits of an owl is its ability to rotate its head. An owl can turn its head up to 270 degrees in either direction. This movement does not damage blood vessels or disrupt blood flow to the brain. Scientists have identified four major biological adaptations that make this possible. A major artery, the vertebral artery, feeds the brain through bony holes in the vertebrae. These holes are ten times larger in diameter than the artery itself. This extra space creates air pockets that allow the artery to move during twisting. Additionally, small vessel connections between the carotid and vertebral arteries allow for uninterrupted blood circulation.

Some owl species also possess unique pigments called porphyrins in their plumage.

Porphyrins are a group of nitrogen-containing pigments, similar to chlorophyll or heme in blood. While other birds use these pigments for eggshells, owls use them in their feathers. These pigments are most common in new feathers but are easily destroyed by sunlight. Interestingly, porphyrins fluoresce under UV light. Biologists use this fluorescence to determine the age of an owl. By using black light to check the intensity of the glow, researchers can distinguish between different generations of feathers.

The study of Strigidae has evolved significantly over time. The family was first introduced by the English zoologist William Elford Leach in 1819. He was the Keeper of Zoology at the British Museum at that time. More recently, a 2020 molecular phylogenetic study by Jessie Salter and collaborators changed our understanding. This study used DNA to show that the family is divided into two sister clades. It also revealed that some traditional genera were paraphyletic, meaning they did not include all descendants of a common ancestor. These findings led researchers like Frank Gill and Pamela Rasmussen to update the official lists of world birds.

Environmental changes and competition also impact these birds. In North America, the barred owl is an invasive species that competes with the northern spotted owl. This competition occurs because both species rely on mature forests of old, tall trees. Deforestation from overlogging and forest fires has reduced the available habitat. As barred owls encroach on these territories, the spotted owl population has declined. This loss could cause a trophic cascade, which is a disruption in the healthy ecosystem. Protecting the mosaic of habitats created by natural, low-severity fires is vital for their survival.

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🖼️ Images & Media (8)
File:Strix nebulosa plumage.jpg
Strix nebulosa plumage.jpg
File:Squelette de Strigidae MHNT.jpg
Squelette de Strigidae MHNT.jpg
File:Pulsatrix perspicillata.jpg
Pulsatrix perspicillata.jpg
File:Bubo blakistoni.jpg
Bubo blakistoni.jpg
File:Tawnyowl03.jpg
Tawnyowl03.jpg
File:Forest_Owlet_Athene_blewitti_by_Ashahar_alias_Krishna_Khan.jpeg
Forest_Owlet_Athene_blewitti_by_Ashahar_al...
File:Coruja-de-crista (Lophostrix cristata).jpg
Coruja-de-crista (Lophostrix cristata).jpg
File:Ornimegalonyx oteroi restoration.jpg
Ornimegalonyx oteroi restoration.jpg
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