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Owls are birds from the order Strigiformes [1] (/ ˈ s t r ɪ dʒ ə f ɔːr m iː z /), which includes over 200 species of mostly solitary and nocturnal birds of prey typified by an upright stance, a large, broad head, binocular vision, binaural hearing, sharp talons, and feathers adapted for silent flight.
The evolution of birds began in the Jurassic Period, with the earliest birds derived from a clade of theropod dinosaurs named Paraves. [1] Birds are categorized as a biological class, Aves. For more than a century, the small theropod dinosaur Archaeopteryx lithographica from the Late Jurassic period was considered to have been the earliest bird.
The bird family Tytonidae, which includes the barn owls Tyto and the bay owls Phodilus, is one of the two families of owls, the other being the true owls or typical owls, Strigidae. They are medium to large owls with large heads and characteristic heart-shaped faces. They have long, strong legs with powerful talons. They also differ from the ...
Rich, Patricia Vickers & David J. Bohaska, 1981. The Ogygoptyngidae, a New Family of Owls from the Paleocene of North America. Alcheringa 5: 95–102. Sankar Chatterjee. The Rise of Birds: 225 Million Years of Evolution, pg. 251. James R. Duncan. Owls of the World: Their Lives, Behavior and Survival, pg. 72.
Cross sectioned great grey owl specimen showing the extent of the body plumage, Zoological Museum, Copenhagen Skeleton of a Strigidae owl. While typical owls (hereafter referred to simply as owls) vary greatly in size, with the smallest species, the elf owl, being a hundredth the size of the largest, the Eurasian eagle-owl and Blakiston's fish owl, owls generally share an extremely similar ...
Close-up of a Caligo wing. The underwing pattern is highly cryptic.It is conceivable that the eye pattern is a generalized form of mimicry.It is known that many small animals hesitate to go near patterns resembling eyes with a light-colored iris and a large pupil, which matches the appearance of the eyes of many predators that hunt by sight.
The evolution of birds is thought to have begun in the Jurassic Period, with the earliest birds derived from theropod dinosaurs. Birds are categorized as a biological class, Aves. The earliest known species in Aves is Archaeopteryx lithographica, from the Late Jurassic period. Modern phylogenetics place birds in the dinosaur clade Theropoda.
A turning point came in the early twentieth century with the writings of Gerhard Heilmann of Denmark.An artist by trade, Heilmann had a scholarly interest in birds and from 1913 to 1916, expanding on earlier work by Othenio Abel, [12] published the results of his research in several parts, dealing with the anatomy, embryology, behavior, paleontology, and evolution of birds. [13]