Owls are some of the most fascinating and mysterious raptors in the world. While many people know a little bit about these birds of prey, some owl facts can surprise even the most experienced birders.
- There are more than 150 species of owls in the world, and some counts indicate more than 220 species depending on how different owls are classified. The greatest owl diversity is found in Asia, and only 19 owl species are found in the United States and Canada.
- Owls are found in all different habitats, and there are different owl species found on all continents except Antarctica. The greatest diversity of owl species is found in forested habitats, but these birds can be found anywhere prey is abundant, including urban and suburban areas.
- All owls have upright posture and forward-facing eyes that give them binocular vision, just like humans. Owls' eyes are not spheres, however, but are tubes that provide better depth perception and allow them to see prey from great distances. Up close an owl's vision is not as clear.
- Many owl species have asymmetrical ears that are different sizes and different heights on their heads. This gives the birds superior hearing and the ability to pinpoint where prey is located, even if they can't see it.
- Several owls species have ear tufts on their heads but they aren't ears at all. These tufts of feathers may indicate the bird's mood, help keep it camouflaged by mimicking branches or leaves, or be used to show aggression or dominance.
- The flattened facial disk of an owl funnels sound to the bird's ears and magnifies it as much as ten times to help the owl hear noises humans can't detect. Different owls have different facial disk shapes, and that shape can be useful for identifying owls.
- An owl's eyes are supported by bony eye sockets and they cannot turn their eyes. Instead, owls rotate their heads up to 270 degrees (135 degrees to either side), but they cannot turn their heads all the way around.
- An owl has three eyelids: one for blinking, one for sleeping, and one for keeping the eye clean and healthy. The third eyelid is also called the nictitating membrane, and many other birds also have it, including other raptors as well as many ducks, anhingas, and dippers.
- A barn owl can eat up to 1,000 mice each year, usually swallowing them whole. Many farmers use barn owl boxes and other tricks try to attract barn owls to help control rodent populations in agricultural fields.
- Owls are carnivorous and will eat rodents, small- or medium-sized mammals, nocturnal insects, fish, and other birds, including smaller owls. After digesting their food, owls regurgitate hard pellets of compressed bones, fur, teeth, feathers, and other materials they couldn't digest. Ornithologists study those pellets to learn more about an owl's diet.
- Owls have zygodactyl feet with two toes pointing forward and two toes pointing backward, and all their toes have sharp talons. This gives the birds a stronger, more powerful grip, so they can be more effective predators.
- Owls have specialized feathers with fringes of varying softness that help muffle sound when they fly. Their broad wings and light bodies also make them nearly silent fliers, which helps them stalk prey more easily.
- For most owl species, females are larger, heavier, and more aggressive than males. If the birds are dimorphic, the female is often more richly colored than the male.
- Not all owls hoot, and owls can make a wide range of other sounds, such as screeches, whistles, barks, growls, rattles, and hisses. During the nesting season, owl calls can often be heard up to a mile away. Female owls generally have higher-pitched voices than their mates.
- Not all owl species are nocturnal. How often an owl is seen during the day depends on the seasonal amount of daylight and darkness, food supplies, and habitat. In times of stress or when food is low, owls may hunt at any time, just to get enough food.
- Most owls do not migrate, but they can be nomadic in searching for the best food sources. Some species, such as the snowy owl, have regular irruptions and will sometimes appear unexpectedly far outside their regular range.
- A group of owls is called a parliament, wisdom, bazaar, or study. Baby owls are called owlets.
- Owls have been found in the fossil record up to 58 million years ago. The largest recorded owl fossil, Orinmegalonyx oteroi, stood about three feet tall.
- Owls have long been cultural symbols, and they have been found in cave paintings in France, in Egyptian hieroglyphics, and even in Mayan art. Today, owl superstitions and legends associate the birds with bad luck, death, and stealing souls in many cultures.
- The biggest modern threats to owls are habitat loss, pesticides that poison the birds and their food supplies, and human persecution because of negative superstitions. Vehicle collisions, wire fences, and even well-meaning birders can also be hazardous to owls.