There are some 9,700 species of birds alive today that inhabit a wide range of habitats including wetlands, woodlands, mountains, deserts, tundra, coasts and the open ocean. To better understand the immense diversity of birds, it is useful to examine the main groups of birds. Although there are several different ways experts classify birds into subgroups, on this website we recognize that there are 30 groups of birds:
Albatrosses and petrels, also known as tubenoses, are a group of seabirds that includes albatrosses, fulmars, prions, shearwaters, storm-petrels and diving petrels. Tubenoses are pelagic birds that spend long periods of time foraging over the open ocean. They have a widespread distribution and occur throughout most oceanic regions of the world. Tubenoses return to land only to breed. They select nesting sites on remote islands and on rugged coastal cliffs. There are 107 species of tubenoses.
Birds of prey, also known as raptors, are formidable avian predators, armed with powerful talons, hooked beaks and acute eyesight. Raptors generally have broad wings well-suited for soaring. Raptors hunt by day and feed on a variety of prey including fish, small mammals, reptiles and carrion. Raptors first appeared during the Middle Eocene. The group includes eagles, hawks, kites, falcons and old world vultures and comprises a total of 304 species.
Buttonquails are a small group of birds consisting of 15 species. They have 3 toes on each foot and lack a hindtoe. Although buttonquails resemble quails, they are not closely related to them. Buttonquails inhabit grasslands, scrublands and croplands. They are drab-colored birds and prefer running to flying. Their distribution includes Asia, Africa, Madagascar, Morocco, Algeria, Spain, Portugal, Australia, Malasyia, the Philippines and Papua New Guinea.
Cassowaries and emus together form a group of large flightless birds comprised of just four species—three cassowaries and one emu. Cassowaries inhabit New Guinea and Australia, emus are restricted to New Guinea. Although their ancestors could fly, present-day cassowaries and emus have only tiny vestigial wings that are far too weak to lift their bulky bodies into the air. Their feathers have become limp and shaggy and resemble coarse fur. The two groups occupy different habitats—cassowaries prefer forests while emus opt for scrublands and grasslands.
Cranes and their relatives—the coots, rails, crakes, bustards and trumpeters—form a group that consists of 199 species. The members of this group are varied in their size and appearance, but generally have a short tail, long neck and rounded wings. The cranes are the largest birds in this group, with some species standing five feet tall. The cranes re also some of the most threatened of all bird groups. Most members of this group inhabit wetlands or lead fully aquatic lifestyles.
Cuckoos and turacos, although related and therefore grouped together, are in fact two somewhat distinct groups of birds. Both groups inhabit forests but while cuckoos have a worldwide distribution, turacos are restricted to sub-Saharan Africa. Cuckoos and turacos generally have a bulky body, small head, short beak long tail and broad wings. Cuckoos are dull colored birds but turacos have brightly colored plumage with vibrant reds and greens. There are 161 species of cuckoos and turacos.
Flamingos are an ancient group of filter-feeding birds that survive on a diet of brine shrimp and blue-green algae. Their diet is rich in carotenoids, a class of proteins responsible for their bright pink to crimson plumage. They are highly social birds and form large flocks that feed and travel together. Flamingos inhabit tropical and subtropical regions in South America, the Caribbean, Africa, India and the Middle East. Their preferred habitat includes estuarine lagoons, mangrove swamps, tidal flats and large alkaline or saline lakes. There are five species of flamingos.
Gamebirds are a group of ground-dwelling birds that include chickens, guineafowl, turkeys, peacocks and pheasants. There are, in total, 287 species of gamebirds. Gamebirds have strong feet that they use to scratch at the ground while foraging for food. Some gamebirds have been domesticated by humans—the first of which was the jungle fowl, the ancestor of modern chickens. Other domesticated gamebirds include turkeys and guineafowl. Although in some gamebird species males and females are similar in appearance, a few species—such as pheasants and peacocks—exhibit a striking degree of sexual dimorphism.
Grebes are group of medium-sized freshwater diving birds that have worldwide distribution. There are six genera of grebes that comprise 21 species. Grebes have long necks and pointed bills. During the breeding season, grebes take part in elaborate courtship displays. Both parents are attentive to their young.
Herons, storks and their relatives—bitterns, egrets, spoonbills and ibises—are long-legged, sharp-billed carnivorous birds that inhabit freshwater wetlands. There are about 115 species of storks and herons. Most members of the group are solitary hunters that stalk their prey slowly before striking quickly with their powerful bill. When flying, most herons and egrets coil their necks into an S shape. In contrast, storks fly with their necks extended straight out in front of their body.