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Flightless birds are birds that cannot fly, as they have, through evolution, lost the ability to. [1] There are over 60 extant species, [2] including the well-known ratites (ostriches, emus, cassowaries, rheas, and kiwis) and penguins. The smallest flightless bird is the Inaccessible Island rail (length 12.5 cm, weight 34.7
The following is a list of animated films in the public domain in the United States for which there is a source to verify its status as public domain under the terms of U.S. copyright law. For more information, see List of films in the public domain in the United States .
This is a list of soaring birds, which are birds that can maintain flight without wing flapping, using rising air currents. Many gliding birds are able to "lock" their extended wings by means of a specialized tendon. [1] Bird of prey. Buzzards; Condors; Eagles; Falcons; Harriers; Hawks; Kites; Osprey; Secretary bird; Vultures; Passerine ...
However, some creatures can stay in the same spot, known as hovering, either by rapidly flapping the wings, as do hummingbirds, hoverflies, dragonflies, and some others, or carefully using thermals, as do some birds of prey. The slowest flying non-hovering bird recorded is the American woodcock, at 8 kilometres per hour (5.0 mph). [26]
Lesser flamingos flying in formation. When in gliding flight, the upward aerodynamic force is equal to the weight.In gliding flight, no propulsion is used; the energy to counteract the energy loss due to aerodynamic drag is either taken from the potential energy of the bird, resulting in a descending flight, or is replaced by rising air currents ("thermals"), referred to as soaring flight.
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Dynamic soaring is a flying technique used to gain energy by repeatedly crossing the boundary between air masses of different velocity.Such zones of wind gradient are generally found close to obstacles and close to the surface, so the technique is mainly of use to birds and operators of radio-controlled gliders, but glider pilots are sometimes able to soar dynamically in meteorological wind ...
The boids framework is often used in computer graphics, providing realistic-looking representations of flocks of birds and other creatures, such as schools of fish or herds of animals. It was for instance used in the 1998 video game Half-Life for the flying bird-like creatures seen at the end of the game on Xen , named "boid" in the game files.