Fledging is the stage in a flying animal's life between hatching or birth and becoming capable of flight. This term is most frequently applied to birds, but is also used for bats.For altricial birds, those that spend more time in vulnerable condition in the nest, the nestling and fledging stage can be the same. For precocial birds, those that develop and leave the nest quickly, a short nestling stage precedes a longer fledging stage.
The egg is the organic vessel containing the zygote in which an embryo develops until it can survive on its own, at which point the animal hatches. An egg results from fertilization of an egg cell. Most arthropods, vertebrates, and mollusks lay eggs, although some, such as scorpions, do not.
Birth is the act or process of bearing or bringing forth offspring. In mammals, the process is initiated by hormones which cause the muscular walls of the uterus to contract, expelling the fetus at a developmental stage when it is ready to feed and breathe. In some species the offspring is precocial and can move around almost immediately after birth but in others it is altricial and completely dependent on parenting. In marsupials, the fetus is born at a very immature stage after a short gestational period and develops further in its mother's womb's pouch.
Birds, also known as Aves or avian dinosaurs, are a group of endothermic vertebrates, 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 cm (2 in) bee hummingbird to the 2.75 m (9 ft) ostrich. They rank as the world's most numerically successful class of tetrapods, with approximately ten thousand living species, more than half of these being passerine, or "perching" birds. Birds have whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds. Wings, which evolved from 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 of birds. 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.
All birds are considered to have fledged when the feathers and wing muscles are sufficiently developed for flight. A young bird that has recently fledged but is still dependent upon parental care and feeding is called a fledgling. People often want to help fledglings, as they appear vulnerable, but it is best to leave them alone.The USA National Phenology Network defines the phenophase (or life cycle stage) of fledged young for birds as "One or more young are seen recently departed from the nest. This includes young incapable of sustained flight and young which are still dependent on adults."
In many species, parents continue to care for their fledged young, either by leading them to food sources, or feeding them. Birds are vulnerable after they have left the nest, but before they can fly, though once fledged their chances of survival increase dramatically.
One species, the ancient murrelet, fledges two days after hatching, running from its burrow to the ocean and its calling parents. Once it reaches the ocean, its parents care for it for several weeks. Other species, such as guillemots and terns, leave the nesting site while they are still unable to fly. The fledging behavior of the guillemot is spectacular; the adult leads the chick to the edge of the cliff, where the colony is located, and the chick will then launch itself off, attempting to fly as far as possible, before crash landing on the ocean.
The ancient murrelet is a bird in the auk family. The genus name Synthliboramphus is from Ancient Greek sunthlibo, "to compress", and rhamphos, "bill", and antiquus is Latin for ancient. The English term "murrelet" is a diminutive of "murre", a word of uncertain origins, but which may imitate the call of the common guillemot. Ancient murrelets are called "ancient" because they have grey on the back like a shawl, as worn by the elderly.
The pigeon guillemot is a species of bird in the auk family, Alcidae. One of three species in the genus Cepphus, it is most closely related to the spectacled guillemot. There are five subspecies of the pigeon guillemot; all subspecies, when in , are dark brown with a black iridescent sheen, with a distinctive wing patch broken by a brown-black wedge. Its has a mottled grey and black and white . The long bill is black, as are the claws. The legs, feet, and inside of the mouth are red. It closely resembles the black guillemot, which is slightly smaller and lacks the dark wing wedge present in the pigeon guillemot. Combined, the two form a superspecies.
The tree swallow is a migratory bird of the family Hirundinidae. Found in the Americas, the tree swallow was first described in 1807 by French ornithologist Louis Vieillot as Hirundo bicolor. It has since been moved to its current genus, Tachycineta, within which its phylogenetic placement is debated. The tree swallow has glossy blue-green , with the exception of the blackish wings and tail, and white . The bill is black, the eyes dark brown, and the legs and feet pale brown. The female is generally duller than the male, and the first-year female has mostly brown upperparts, with some blue feathers. Juveniles have brown upperparts, and a grey-brown-washed breast. The tree swallow breeds in the US and Canada. It winters along southern US coasts south, along the Gulf Coast, to Panama and the northwestern coast of South America, and in the West Indies.
The eastern bluebird is a small thrush found in open woodlands, farmlands, and orchards. It is the state bird of Missouri and New York.
The black-backed woodpecker also known as the Arctic three-toed woodpecker is a medium-sized woodpecker inhabiting the forests of North America.
The wood thrush is a North American passerine bird. It is closely related to other thrushes such as the American robin and is widely distributed across North America, wintering in Central America and southern Mexico. The wood thrush is the official bird of the District of Columbia.
The yellow warbler is a New World warbler species. Warblers are the most widespread species in the diverse genus Setophaga, breeding in almost the whole of North America and down to northern South America.
The American oystercatcher, occasionally called the American pied oystercatcher, is a member of family Haematopodidae. Originally called the "sea pie", it was renamed in 1731 when naturalist Mark Catesby observed the bird eating oysters. The current population of American oystercatchers is estimated to be 43,000. There are estimated to be 1,500 breeding pairs along the Atlantic and Gulf Coasts of the US. The bird is marked by its black and white body and a long, thick orange beak.
The green-rumped parrotlet is a species of parrot in the family Psittacidae. It is the nominate species.
The golden-headed quetzal is a strikingly coloured bird in the genus Pharomachrus; it is also referred to as Trogon auriceps. It is found in moist mid-elevation forests from eastern Panama to northern Bolivia.
The square-tailed kite is a medium-sized bird of prey in the family Accipitridae, which also includes many other diurnal raptors such as kites, eagles and harriers.
The fiery-billed aracari or fiery-billed araçari is a toucan, a near-passerine bird. It breeds only on the Pacific slopes of southern Costa Rica and western Panama. The binomial commemorates the German naturalist Alexander von Frantzius.
The brown noddy or common noddy is a seabird in the family Laridae. The largest of the noddies, it can be told from the closely related black noddy by its larger size and plumage, which is dark brown rather than black. The brown noddy is a tropical seabird with a worldwide distribution, ranging from Hawaii to the Tuamotu Archipelago and Australia in the Pacific Ocean, from the Red Sea to the Seychelles and Australia in the Indian Ocean and in the Caribbean to Tristan da Cunha in the Atlantic Ocean. The brown noddy is colonial, usually nesting on elevated situations on cliffs or in short trees or shrubs. It only occasionally nests on the ground. A single egg is laid by the female of a pair each breeding season.
The Montserrat oriole is a medium-sized black-and-yellow icterid endemic to the island of Montserrat.
The white-throated swallow is a small bird in the swallow family. It is a common species, found in southern Africa, which has benefited from the increased nesting opportunities presented by the construction of bridges and dams.
The fluttering shearwater is a species of seabird in the family Procellariidae.
The plumbeous ibisTheristicus caerulescens, also formerly called the blue ibis, is a large distinctive ibis species endemic to parts of central South America.
The southern pied babbler is a species of bird in the Leiothrichidae family, found in dry savannah of Botswana, Namibia, South Africa, and Zimbabwe.
The cactus wren is a species of wren that is endemic to parts of the southwestern United States and northern and central Mexico. There are eight generally recognized subspecies. The wren has prominent white eyebrows that stretch to the nape of the neck. They are brown with black and white spots as markings. The tail, as well as certain flight feathers, are also barred in black and white. The chest is whiter, while the underparts are cinnamon-buff colored. Their song is harsh and raspy; ornithologists have described it as like a car engine that will not start. Cactus wrens are well-adapted to their native desert environment, and can meet their water needs from their diet – which consists chiefly of insects, supplemented with some plant matter. They are ground feeders and spend much of their time on the ground searching for food, as they are somewhat poor fliers.
Golden eagles usually mate for life. A breeding pair is formed in a courtship display. This courtship includes undulating displays by both in the pair, with the male bird picking up a piece of rock and dropping it only to enter into a steep dive and catch it in mid-air, repeating the maneuver 3 or more times. The female takes a clump of earth and drops and catches it in the same fashion. Small sticks may also be used in this display. Compared to the bald eagle, golden eagles do not repeat courtship displays annually and rarely engage in talon-locking downward spirals.
Allofeeding is a type of food sharing behaviour observed in cooperatively breeding species of birds. Allofeeding refers to a parent, sibling or unrelated adult bird feeding altricial hatchlings, which are dependent on parental care for their survival. Allofeeding also refers to food sharing between adults of the same species. Allofeeding can occur between mates during mating rituals, courtship, egg laying or incubation, between peers of the same species, or as a form of parental care.