|Barred owl (Strix varia)|
Owls are medium to large birds of prey of the order Strigiformes, the nocturnal equivalent of the falcons, hawks, and eagles.
Owls are classified into two main families: Strigidae and Tytonidae.
Strigidae consists of nearly 200 living species of what are considered typical or true owls. These birds have large heads with rounded facial disks, and many species bear tufts of feathers on their heads resembling "ears". They range in size from five inches for the elf owl (Micrathene whitneyi) to seventy inches in the European eagle-owl (Bubo bubo) and great grey owl (Strix nebulosa).
- Aegolius; saw-whet owls
- Asio; eared owls
- Athene; Little owl, and three species of owlet
- Bubo; horned owls, eagle-owls and fish-owls
- Ciccaba; small genus of four species, formerly classified within Strix
- Glaucidium; pygmy owls
- Gymnoglaux; Bare-legged owl or Cuban screech-owl
- Lophostrix; Crested owl
- Jubula; Maned owl
- Megascops; screech-owls
- Micrathene; Elf owl
- Mimizuku; Giant scops-owl or Mindanao eagle-owl
- Nesasio; Fearful owl
- Ninox; Australasian hawk-owls
- Otus; scops-owls
- Pseudoscops; Jamaican owl, Striped owl
- Ptilopsis; white-faced owls
- Pulsatrix; spectacled owls
- Pyrroglaux; Palau owl
- Strix; earless owls
- Surnia; Northern hawk-owl
- Uroglaux; Papuan hawk-owl
- Xenoglaux; Long-whiskered owlet
Tytonidae consists of 16 living species of barn and bay owls, in which the main difference from true owls is a heart-shaped facial disk. The common barn owl (Tyto alba) is the most widely distributed owl species on earth.
- Phodilus; bay owls
- Tyto; masked and barn owls
Owls are found worldwide except in Antarctica. Terrestrial habitats include coniferous, temperate, and tropical forests, grasslands, deserts, and arctic tundra.
Owls consume small mammals, birds, reptiles, and insects, with several species specialized in catching fish. Unlike the diurnal birds of prey, they swallow their food whole without tearing, with the indigestible parts (hair or feathers, and bone) regurgitated several hours later. These "owl pellets" as they are called are typically found in the debris beneath nests and roosting sites, giving researchers data into their feeding habits as well as how they control a given animal population.
Due to their nocturnal presence, eerie calls and striking skull-like faces, owls have often been associated with death, magic and the macabre. They have often appeared in mythology and fiction as the companions of witches or wizards. A recent example of this is their role in J.K. Rowling's Harry Potter novels, in which owls are kept by trainee wizards as pets, but also used for postal delivery.