flightless bird

animal

Any one of several birds that have evolved to adapt to new environments without the ability to fly. The majority of living creatures belong to the order Struthioniformes (which includes the ostrich, the rhea, the cassowary, the kiwi, and the emu); nevertheless, they are often referred to as ratites. Penguins (order Sphenisciformes), which are also flightless, are unrelated to ratites. Fossil records and historical records provide information on several extinct forms, such as the dodo.

Origins

Scientists generally agree that flightless birds descend from birds that could fly. The reason why these birds lost their ability to fly is not entirely clear. Flying was thought to be unnecessary for ancient birds that colonized habitats without predators, since they no longer required that adaptation to escape. Natural selection favoured other traits over time, and the flightlessness of these birds was passed on to their descendants. Several flightless bird species, however, became extinct after they were decimated by predators such as rats, dogs, pigs, and humans, who invaded their environments and decimated their populations. Birds that had evolved other defenses against predation, such as the ability to run at high speeds, survived.

Characteristics

Flightless birds have different bone structures and muscles than other birds due to their absence or different shape. Flight muscles are attached to a keel, which is a ridge on the sternum, or breastbone, in birds that fly. Ratites lack this keel, and the lack of it is one reason their muscles are unsuitable for flight.

Penguins, on the other hand, have retained the keel, which has evolved to accommodate the bird's aquatic lifestyle. Birds' forelimbs have also changed, but their flight muscles are retained. Penguins' forelimbs have evolved from winglike structures for powered flight to paddlelike structures for swimming. The feet of penguins are also positioned much farther back on the body than those of other birds. In contrast to most birds, penguins walk on their toes rather than on their soles (plantigrade locomotion).

The size of the bird and the leg bone and toe structure are closely related in ratites. Many hollow bones are found in the skeletons of flying birds. Since ratites are not required to lift their bodies off the ground for flying, however, they have large bodies supported by heavy leg bones and strong feet adapted to running. In addition, because ratites live on the ground and do not need to grasp tree branches, they lack the opposable toe of many flying birds.

Extinct species

Fossil records contain numerous extinct flightless birds, and some have become extinct because of human activities. The elephant birds (Aepyornis, Mullerornis, and Vorombe) live on the island of Madagascar. Carbon dating indicates that the longest-surviving elephant bird species, A. hillebrandti, lived on the island until deforestation and hunting wiped it out about 1,300–1,560 years ago. V. titan is the largest species of elephant bird, standing 3 metres (10 feet) high and weighing approximately 650 kg (1.433 pounds). V. titan could have weighed as much as 1,895 pounds (860 kg), making it the largest bird that ever lived. The species survived until about 2,500 years ago.

Other examples include the dodo (Raphus cucullatus), a stocky, odd-looking bird native to Mauritius that weighed about 23 kg (50 pounds), and the moas, a group of fast-running birds native to New Zealand that rose to heights of roughly 0.5 meters (1.6 feet) to more than 1.8 meters (about 6 feet). By 1690, the dodo had succumbed to egg predation caused by pigs and rats introduced by Portuguese sailors, as well as hunting by the sailors themselves. It is believed that the ancestors of the Maori people hunted each of the 11 known moa species to extinction between 1250 and 1350.

bird-watching

hobby

A popular pastime and scientific sport developed almost entirely in the 20th century, bird-watching is the observation of live birds in their natural habitat. Almost all students of birds in the 19th century used guns and could only identify a species when it was in their hands. Bird-watching today is largely enabled by the development of optical aids, such as binoculars, which enable people to see and study wild birds better than ever before, without harming them.

Since the 1880s, wild birds have attracted a lot of attention. Great Britain was the first country to make bird-watching popular, followed by the United States not far behind. Eventually, it became equally popular in Scandinavia, the Netherlands, Germany, Switzerland, and the older Commonwealth countries.

The interest in bird-watching has been stimulated by bird books going back to Gilbert White's Natural History of Selborne (1788), John James Audubon's illustrated Birds of America (1827–38), and culminating in such essentials as H.F. Witherby's five-volume Handbook of British Birds (1938–41) and Roger Tory Peterson's Field Guide to the Birds (1947), which lists field marks of all North American birds found east of the Rocky Mountains. Many other regions have similar works available.

A number of journals and magazines, including Audubon Magazine (United States), British Birds (England), and La Terre et la vie (France), have also contributed to the growth of interest.

Birdwatching is a relatively inexpensive activity, which makes it a popular attraction. If you have binoculars, a field book to help with identification, and a notebook to keep track of sightings, you do not need to travel. Bird watchers often visit feeding stations. To determine dispersal, habitat, and migration patterns of birds, researchers compile lists of observations compiled by members of local bird-watching societies.

In the 1930s, amateur birdwatching fieldwork, including photography, increased significantly. Amateur bird watchers participate in cooperative investigations organized by the British Trust for Ornithology, such as sample censuses of herons and great crested grebes, and surveys of gull winter roosts. The International Wildfowl Research Bureau conducts a coordinated international wildfowl count in western Europe.

locust bird

common name of several birds

An African bird capable of eating grasshoppers and locusts, especially the black-winged pratincole (see pratincole). Locust birds are called rose-colored starlings in India.

songbird

bird

Songsters are members of the suborder Passeri (or Oscines), in the order Passeriformes, which includes nearly half of all bird species worldwide. These birds are most commonly kept in cages. As with songbirds, songbirds possess highly developed vocal organs, but not all of them use them in a melodious manner. Their classification is debatable. Among the most distinctive families are the Alaudidae (larks) and Hirundinidae (swallows).

There are kinglets, sunbirds, and crows of varying sizes among songbirds. Land birds, they live in a wide variety of habitats, from grasslands to forests. There are some songbirds that are great singers, such as thrushes, but some have harsh voices, such as crows, and some do not sing at all. Several anatomical features distinguish Songbirds from other perching birds, including the more complicated vocal organ, or syrinx.

The syrinx, as the voice-producing structure is called, is located where the windpipe divides into the bronchial tubes that lead to the lungs. A syrinx is an intricately constructed organ with a bony framework and membranes within which the air passes rapidly during exhalation, producing all the bird's sounds. The tension on the membranes is adjusted by syringeal muscles and their controlling nerves. True songbirds have the most complex song boxes. However, a complicated syrinx is not the only factor determining singing ability. Some true songbirds don't sing at all. Some birds have an elongated, elaborately coiled windpipe. The elongation may be enclosed within the sternum, or breast bone. Some birds-of-paradise, known as manucodes, have a coiled, elongated windpipe between their skin and flesh. It is likely that this lengthening of the windpipe contributes to the voice's resonance.

In addition to songs, birds use a variety of calls to communicate with one another. Bird songs are the vocalizations used by males during courtship and breeding, primarily to announce his readiness for mating, to attract the female and possibly stimulate her sexually, to keep the pair together, and to inform rival males of the territory from which they have been forbidden to invade. Males also use their calls to repel intruders in addition to displaying a threat. Sometimes, however, similar songs are sung spontaneously without apparent reason. In tropical species, females sing sometimes, and pairs may duet, possibly to reinforce their bond. Song delivery usually occurs from a series of regularly used perches. Flight songs are particularly common among grassland species.

Humans are not necessary to enjoy bird songs. Hooting from the owl, repetitive phrases of the North American whippoorwill, the crazed, repeated whistling of the Malayan cuckoo, and the repeated notes of the African tinkerbird are all songs.

The best singers are subjectively chosen. Nightingales in European literature (Erithacus, Luscinia, megarhynchos) are small thrushes who are regarded as being the most celebrated artists. The European skylark (Alaudia arvensis) was also a favorite of the poets. A mockingbird (Mimus polyglottos) is a wonderful performer in North America. Its song is rich, melodious, and long-continuing. Australia's lyrebirds, which are not true songbirds, have songs that are extraordinarily rich in variety and intensity, and they have a dramatic quality. In addition to true songbirds, some birds of other groups have pleasing or musical song, such as the screech owl's quavering trill and the bobwhite quail's cheerful whistle.