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Owls are enigmatic birds, by turns mysterious, lovable, or spooky, depending on who you ask. With over 200 species living on every continent except Antarctica, owls have super-tuned senses that help them hunt prey all over the world. And they’re pretty darn cute, too.
There are roughly 225 species of owls in the world, depending on how various geographic populations and subspecies are classified. These birds come in many shapes, sizes, and colors, but they are all related and belong to one of two scientific bird family classifications. The Strigidae owls are the typical owls or true owls, and this family includes the majority of owl species. They are heavily camouflaged birds and have large heads and round or oval facial disks. The Tytonidae owls, or barn owls, have more typically countershaded plumage and heart-shaped facial disks, and their body shape is a bit more tapered and slender than the true owls. Regardless of which family these birds belong to, however, they are always able to capture birders’ interest.
Instead of spherical eyeballs, owls have “eye tubes” that go far back into their skulls—which means their eyes are fixed in place, so they have to turn their heads to see. The size of their eyes helps them see in the dark, and they’re far-sighted, which allows them to spot prey from yards away. Up close, everything is blurry, and they depend on small, hair-like feathers on their beaks and feet to feel their food.
The ways owls behave can also help set them apart. While different owls have evolved different behaviors that best suit their habitat, hunting and other needs, these types of behaviors can also be clues for birders to find, identify and appreciate owls.
- Activity Period: Many owls are crepuscular or nocturnal, as opposed to other raptors that are more strictly diurnal. Owls have evolved keen senses to help them hunt more efficiently in low light conditions, either at night or in twilight or dawn periods. Owls are also often active when the moon is bright.
- Diet: Owls are carnivorous and eat a wide variety of other animals, including rodents, insects, fish and larger mammals. Very few owls are avivorous, however, because the birds they would eat as prey are not active when owls typically hunt.
- Pellets: After eating, owls regurgitate pellets filled with indigestible fur, bones and other material they cannot pass through their digestive tracts. Ornithologists often dissect owl pellets to study the birds’ feeding preferences and diet composition.
- Flight: Owls can fly virtually silently because of a fringe on the leading edge of their primary feathers that helps muffle sound. Their wings are broad and large for their body size to help the birds stay aloft with minimal effort, which also reduces flight noises.
- Voice: The classic “hoot” call is not the only sound owls make. Many owls have a wide range of vocal sounds, including hisses, whistles, screeches, screams, and purrs. Owls will also use bill clacks for communication, especially when agitated.
- Aggression: Many owls are extremely territorial, particularly around active nests. Birders should always be cautious when near an owl nest, because the parent birds may attack anything – and anyone – they might consider a threat to their owlets.