Birds are a group of warm-blooded vertebrates constituting the class Aves, characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton. Birds live worldwide and range in size from the 5.5 cm (2.2 in) bee hummingbird to the 2.8 m common ostrich. There are over 11,000 living species, more than half of which are passerine, or "perching" birds. Birds have wings whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds. Wings, which are modified forelimbs, gave birds the ability to fly, although further evolution has led to the loss of flight in some birds, including ratites, penguins, and diverse endemic island species. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds, have further evolved for swimming. The study of birds is called ornithology.
The stratosphere is the second layer of the atmosphere of Earth, located above the troposphere and below the mesosphere. The stratosphere is an atmospheric layer composed of stratified temperature layers, with the warm layers of air high in the sky and the cool layers of air in the low sky, close to the planetary surface of the Earth. The increase of temperature with altitude is a result of the absorption of the Sun's ultraviolet (UV) radiation by the ozone layer. The temperature inversion is in contrast to the troposphere, and near the Earth's surface, where temperature decreases with altitude.
Birds of prey or predatory birds, also known as raptors, are hypercarnivorous bird species that actively hunt and feed on other vertebrates. In addition to speed and strength, these predators have keen eyesight for detecting prey from a distance or during flight, strong feet with sharp talons for grasping or killing prey, and powerful, curved beaks for tearing off flesh. Although predatory birds primarily hunt live prey, many species also scavenge and eat carrion.
The bearded vulture, also known as the lammergeier and ossifrage, is a very large bird of prey in the monotypic genus Gypaetus. Traditionally considered an Old World vulture, it actually forms a separate minor lineage of Accipitridae together with the Egyptian vulture, its closest living relative. It is not much more closely related to the Old World vultures proper than to, for example, hawks, and differs from the former by its feathered neck. Although dissimilar, the Egyptian and bearded vulture each have a lozenge-shaped tail—unusual among birds of prey. It is vernacularly known as Homa, a bird in Iranian mythology.
The turkey vulture is the most widespread of the New World vultures. One of three species in the genus Cathartes of the family Cathartidae, the turkey vulture ranges from southern Canada to the southernmost tip of South America. It inhabits a variety of open and semi-open areas, including subtropical forests, shrublands, pastures, and deserts.
The black vulture, also known as the American black vulture, Mexican vulture, zopilote, urubu, or gallinazo, is a bird in the New World vulture family whose range extends from the southeastern United States to Perú, Central Chile and Uruguay in South America. Although a common and widespread species, it has a somewhat more restricted distribution than its compatriot, the turkey vulture, which breeds well into Canada and all the way south to Tierra del Fuego. It is the only extant member of the genus Coragyps, which is in the family Cathartidae. Despite the similar name and appearance, this species is not closely related to the Eurasian black vulture, an Old World vulture, of the family Accipitridae. For ease of locating animal corpses, black vultures tend to inhabit relatively open areas with scattered trees, such as chaparral, in addition to subtropical forested areas and parts of the Brazilian pantanal.
The bar-headed goose is a goose that breeds in Central Asia in colonies of thousands near mountain lakes and winters in South Asia, as far south as peninsular India. It lays three to eight eggs at a time in a ground nest. It is known for the extreme altitudes it reaches when migrating across the Himalayas.
The cinereous vulture is a large raptor in the family Accipitridae and distributed through much of temperate Eurasia. It is also known as the black vulture, monk vulture and Eurasian black vulture. With a body length of 1.2 m, 3.1 m (10 ft) across the wings and a maximum weight of 14 kg (31 lb), it is the largest Old World vulture and largest member of the Accipitridae family.
Bird migration is the regular seasonal movement, often north and south, along a flyway, between breeding and wintering grounds. Many species of bird migrate. Migration carries high costs in predation and mortality, including from hunting by humans, and is driven primarily by the availability of food. It occurs mainly in the northern hemisphere, where birds are funnelled onto specific routes by natural barriers such as the Mediterranean Sea or the Caribbean Sea.
The Accipitriformes are an order of birds that includes most of the diurnal birds of prey, including hawks, eagles, vultures, and kites, but not falcons.
The Canada goose, sometimes called Canadian goose, is a large wild goose with a black head and neck, white cheeks, white under its chin, and a brown body. It is native to the arctic and temperate regions of North America, and it is occasionally found during migration across the Atlantic in northern Europe. It has been introduced to France, the United Kingdom, Ireland, Finland, Sweden, Denmark, New Zealand, Japan, Chile, Argentina, and the Falkland Islands. Like most geese, the Canada goose is primarily herbivorous and normally migratory; often found on or close to fresh water, the Canada goose is also common in brackish marshes, estuaries, and lagoons.
Rüppell's vulture, also called Rüppell's griffon vulture, named after Eduard Rüppell, is a large bird of prey, mainly native to the Sahel region and East Africa. The former population of 22,000 has been decreasing due to loss of habitat, incidental poisoning, and other factors. Known also as Rüppell's griffon, Rueppell's griffon, Rüppell's griffin vulture, Rueppell's vulture and other variants, it is not to be confused with a different species, the griffon vulture. Rüppell's vulture is considered to be the highest-flying bird, with confirmed evidence of a flight at an altitude of 11,300 m (37,000 ft) above sea level.
The Andean condor is a South American New World vulture and is the only member of the genus Vultur. It is found in the Andes mountains and adjacent Pacific coasts of western South America. With a maximum wingspan of 3.3 m and weight of 15 kg (33 lb), the Andean condor is one of the largest flying birds in the world, and is generally considered to be the largest bird of prey in the world.
The common nighthawk or bullbat is a medium-sized crepuscular or nocturnal bird of the Americas within the nightjar (Caprimulgidae) family, whose presence and identity are best revealed by its vocalization. Typically dark, displaying cryptic colouration and intricate patterns, this bird is difficult to spot with the naked eye during the day. This bird is most conspicuous when in its buoyant and erratic flight. The most remarkable feature of this aerial insectivore is its small beak that belies the massiveness of its mouth. Some claim appearance similarities to owls. With its horizontal stance and short legs, the common nighthawk does not travel frequently on the ground, instead preferring to perch horizontally, parallel to branches, on posts, on the ground or on a roof. The males of this species may roost together but the bird is primarily solitary. The common nighthawk shows variability in territory size.
The king vulture is a large bird found in Central and South America. It is a member of the New World vulture family Cathartidae. This vulture lives predominantly in tropical lowland forests stretching from southern Mexico to northern Argentina. It is the only surviving member of the genus Sarcoramphus, although fossil members are known.
The blackpoll warbler is a New World warbler. Breeding males are mostly black and white. They have a prominent black cap, white cheeks, and white wing bars. The blackpoll breeds in forests of northern North America, from Alaska throughout most of Canada, to the Adirondack Mountains of New York as well as New England in the Northeastern United States. They are a common migrant throughout much of North America. In fall, they fly south to the Greater Antilles and the northeastern coasts of South America in a non-stop long-distance migration over open water, averaging 2,500 km (1,600 mi), one of the longest-distance non-stop overwater flights ever recorded for a migratory songbird. Rare vagrants to western Europe, they are one of the more frequent transatlantic passerine wanderers.
A bird strike is a collision between an airborne animal and a moving vehicle. The term is also used for bird deaths resulting from collisions with structures, such as power lines, towers and wind turbines.
The black caracara is a species of bird of prey in the family Falconidae found in Amazonian and French Guianan lowlands, occurring commonly along rivers. They are locally referred to as Ger' futu busikaka in the Republic of Suriname, and juápipi {nẽjõmbʌ} by the Emberá of Panamá and Colombia. However, both of these names refer to multiple bird species within the Falconidae. German-Brazilian ornithologist Helmut Sick also referred to this species as gavião-de-anta, literally translating to "tapir-hawk".
Bird–window collisions are a problem in both low- and high-density areas worldwide. Birds strike glass because reflective or transparent glass is often invisible to them. It is estimated that between 100 million and 1 billion birds are killed by collisions in the United States annually, and an estimated 16 to 42 million birds are likewise killed each year in Canada.
Organisms can live at high altitude, either on land, in water, or while flying. Decreased oxygen availability and decreased temperature make life at such altitudes challenging, though many species have been successfully adapted via considerable physiological changes. As opposed to short-term acclimatisation, high-altitude adaptation means irreversible, evolved physiological responses to high-altitude environments, associated with heritable behavioural and genetic changes. Among vertebrates, only few mammals and certain birds are known to have completely adapted to high-altitude environments.
