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An egg is the organic vessel containing the zygote in which an animal embryo develops until it can survive on its own; at which point the animal hatches. An egg results from fertilization of an ovum. Most arthropods, vertebrates, and mollusks lay eggs, although some, such as scorpions and most mammals, do not. Reptile
Reptile
eggs, bird eggs, and monotreme eggs are laid out of water, and are surrounded by a protective shell, either flexible or inflexible. Eggs laid on land or in nests are usually kept within a warm and favorable temperature range while the embryo grows. When the embryo is adequately developed it hatches, i.e. breaks out of the egg's shell. Some embryos have a temporary egg tooth they use to crack, pip, or break the eggshell or covering. The largest recorded egg is from a whale shark, and was 30 cm × 14 cm × 9 cm (11.8 in × 5.5 in × 3.5 in) in size.[1] Whale shark
Whale shark
eggs typically hatch within the mother. At 1.5 kg (3.3 lb) and up to 17.8 cm × 14 cm (7.0 in × 5.5 in), the ostrich egg is the largest egg of any living bird,[2] though the extinct elephant bird and some dinosaurs laid larger eggs. The bee hummingbird produces the smallest known bird egg, which weighs half of a gram (around 0.02 oz). Some eggs laid by reptiles and most fish, amphibians, insects and other invertebrates can be even smaller. Reproductive structures similar to the egg in other kingdoms are termed "spores," or in spermatophytes "seeds," or in gametophytes "egg cells".

Contents

1 Eggs of different animal groups

1.1 Fish
Fish
and amphibian eggs 1.2 Bird
Bird
eggs

1.2.1 Colors 1.2.2 Shell 1.2.3 Shape 1.2.4 Predation 1.2.5 Various examples

1.3 Amniote
Amniote
eggs and embryos 1.4 Mammalian eggs 1.5 Invertebrate
Invertebrate
eggs

2 Evolution
Evolution
and structure 3 Scientific classifications

3.1 Egg
Egg
size and yolk

3.1.1 Microlecithal 3.1.2 Mesolecithal 3.1.3 Macrolecithal

3.2 Egg-laying reproduction

4 Human use

4.1 Food

4.1.1 Eggs and Kashrut

4.2 Vaccine manufacture 4.3 Culture

5 Collecting 6 Gallery 7 See also 8 References

Eggs of different animal groups Further information: egg cell Several major groups of animals typically have readily distinguishable eggs.

Overview of eggs from various animals

Class Types of eggs Development

Jawless fish Mesolecithal eggs, especially large in hagfish[3] Larval
Larval
stage in lampreys, direct development in hagfish.[4][5]

Cartilaginous fish Macrolecithal eggs with egg capsule[3] Direct development, viviparity in some species[6]

Bony fish Macrolecithal eggs, small to medium size, large eggs in the coelacanth[7] Larval
Larval
stage, ovovivipary in some species.[8]

Amphibians Medium-sized mesolecithal eggs in all species.[7] Tadpole
Tadpole
stage, direct development in some species.[7]

Reptiles Large macrolecithal eggs, develop independent of water.[9] Direct development, some ovoviviparious

Birds Large to very large macrolecithal eggs in all species, develop independent of water.[3] The young more or less fully developed, no distinct larval stage.

Mammals Macrolecithal eggs in monotremes and marsupials, extreme microlecithal eggs in placental mammals.[3] Young little developed with indistinct larval stage in monotremes and marsupials, direct development in placentals.

Fish
Fish
and amphibian eggs See also: Ichthyoplankton
Ichthyoplankton
and Spawn (biology)

Salmon
Salmon
eggs in different stages of development. In some only a few cells grow on top of the yolk, in the lower right the blood vessels surround the yolk and in the upper left the black eyes are visible.

Diagram of a fish egg: A. vitelline membrane B. chorion C. yolk D. oil globule E. perivitelline space F. embryo

Salmon
Salmon
fry hatching. The larva has grown around the remains of the yolk and the remains of the soft, transparent egg are discarded.

The most common reproductive strategy for fish is known as oviparity, in which the female lays undeveloped eggs that are externally fertilized by a male. Typically large numbers of eggs are laid at one time (an adult female cod can produce 4–6 million eggs in one spawning) and the eggs are then left to develop without parental care. When the larvae hatch from the egg, they often carry the remains of the yolk in a yolk sac which continues to nourish the larvae for a few days as they learn how to swim. Once the yolk is consumed, there is a critical point after which they must learn how to hunt and feed or they will die. A few fish, notably the rays and most sharks use ovoviviparity in which the eggs are fertilized and develop internally. However the larvae still grow inside the egg consuming the egg's yolk and without any direct nourishment from the mother. The mother then gives birth to relatively mature young. In certain instances, the physically most developed offspring will devour its smaller siblings for further nutrition while still within the mother's body. This is known as intrauterine cannibalism. In certain scenarios, some fish such as the hammerhead shark and reef shark are viviparous, with the egg being fertilized and developed internally, but with the mother also providing direct nourishment. The eggs of fish and amphibians are jellylike. Cartilagenous fish (sharks, skates, rays, chimaeras) eggs are fertilized internally and exhibit a wide variety of both internal and external embryonic development. Most fish species spawn eggs that are fertilized externally, typically with the male inseminating the eggs after the female lays them. These eggs do not have a shell and would dry out in the air. Even air-breathing amphibians lay their eggs in water, or in protective foam as with the Coast foam-nest treefrog, Chiromantis xerampelina. Bird
Bird
eggs Main article: bird egg Bird
Bird
eggs are laid by females and incubated for a time that varies according to the species; a single young hatches from each egg. Average clutch sizes range from one (as in condors) to about 17 (the grey partridge). Some birds lay eggs even when not fertilized (e.g. hens); it is not uncommon for pet owners to find their lone bird nesting on a clutch of unfertilized eggs, which are sometimes called wind-eggs. Colors

Guillemot
Guillemot
eggs

The default color of vertebrate eggs is the white of the calcium carbonate from which the shells are made, but some birds, mainly passerines, produce colored eggs. The pigment biliverdin and its zinc chelate give a green or blue ground color, and protoporphyrin produces reds and browns as a ground color or as spotting. Non-passerines typically have white eggs, except in some ground-nesting groups such as the Charadriiformes, sandgrouse and nightjars, where camouflage is necessary, and some parasitic cuckoos which have to match the passerine host's egg. Most passerines, in contrast, lay colored eggs, even if there is no need of cryptic colors. However some have suggested that the protoporphyrin markings on passerine eggs actually act to reduce brittleness by acting as a solid state lubricant.[10] If there is insufficient calcium available in the local soil, the egg shell may be thin, especially in a circle around the broad end. Protoporphyrin
Protoporphyrin
speckling compensates for this, and increases inversely to the amount of calcium in the soil.[11] For the same reason, later eggs in a clutch are more spotted than early ones as the female's store of calcium is depleted. The color of individual eggs is also genetically influenced, and appears to be inherited through the mother only, suggesting that the gene responsible for pigmentation is on the sex determining W chromosome (female birds are WZ, males ZZ). It used to be thought that color was applied to the shell immediately before laying, but this research shows that coloration is an integral part of the development of the shell, with the same protein responsible for depositing calcium carbonate, or protoporphyrins when there is a lack of that mineral. In species such as the common guillemot, which nest in large groups, each female's eggs have very different markings, making it easier for females to identify their own eggs on the crowded cliff ledges on which they breed. Shell Bird
Bird
eggshells are diverse. For example:

cormorant eggs are rough and chalky tinamou eggs are shiny duck eggs are oily and waterproof cassowary eggs are heavily pitted

Tiny pores in bird eggshells allow the embryo to breathe. The domestic hen's egg has around 7000 pores.[12] Shape Most bird eggs have an oval shape, with one end rounded and the other more pointed. This shape results from the egg being forced through the oviduct. Muscles contract the oviduct behind the egg, pushing it forward. The egg's wall is still shapeable, and the pointed end develops at the back. Long, pointy eggs are an incidental consequence of having a streamlined body typical of birds with strong flying abilities; flight narrows the oviduct, which changes the type of egg a bird can lay.[13] Cliff-nesting birds often have highly conical eggs. They are less likely to roll off, tending instead to roll around in a tight circle; this trait is likely to have arisen due to evolution via natural selection. In contrast, many hole-nesting birds have nearly spherical eggs. Predation Many animals feed on eggs. For example, principal predators of the black oystercatcher's eggs include raccoons, skunks, mink, river and sea otters, gulls, crows and foxes. The stoat (Mustela erminea) and long-tailed weasel (M. frenata) steal ducks' eggs. Snakes of the genera Dasypeltis
Dasypeltis
and Elachistodon
Elachistodon
specialize in eating eggs. Brood parasitism
Brood parasitism
occurs in birds when one species lays its eggs in the nest of another. In some cases, the host's eggs are removed or eaten by the female, or expelled by her chick. Brood parasites include the cowbirds and many Old World cuckoos. Various examples

An average whooping crane egg is 102 mm (4.0 in) long and weighs 208 g (7.3 oz)

Eurasian oystercatcher
Eurasian oystercatcher
eggs camouflaged in the nest

Egg
Egg
of a senegal parrot, a bird that nests in tree holes, on a 1 cm (0.39 in) grid

Eggs of ostrich, emu, kiwi and chicken

Finch
Finch
egg next to American dime

Eggs of duck, goose, guineafowl and chicken

Eggs of ostrich, cassowary, chicken, flamingo, pigeon and blackbird

Egg
Egg
of an emu

Amniote
Amniote
eggs and embryos

Turtle
Turtle
eggs in a nest dug by a female common snapping turtle (Chelydra serpentina)

Like amphibians, amniotes are air-breathing vertebrates, but they have complex eggs or embryos, including an amniotic membrane. Amniotes include reptiles (including dinosaurs and their descendants, birds) and mammals. Reptile
Reptile
eggs are often rubbery and are always initially white. They are able to survive in the air. Often the sex of the developing embryo is determined by the temperature of the surroundings, with cooler temperatures favouring males. Not all reptiles lay eggs; some are viviparous ("live birth"). Dinosaurs laid eggs, some of which have been preserved as petrified fossils. Among mammals, early extinct species laid eggs, as do platypuses and echidnas (spiny anteaters). Platypuses and two genera of echidna are Australian monotremes. Marsupial
Marsupial
and placental mammals do not lay eggs, but their unborn young do have the complex tissues that identify amniotes. Mammalian eggs The eggs of the egg-laying mammals (the platypus and the echidnas) are macrolecithal eggs very much like those of reptiles. The eggs of marsupials are likewise macrolecithal, but rather small, and develop inside the body of the female, but do not form a placenta. The young are born at a very early stage, and can be classified as a "larva" in the biological sense.[14] In placental mammals, the egg itself is void of yolk, but develops an umbilical cord from structures that in reptiles would form the yolk sac. Receiving nutrients from the mother, the fetus completes the development while inside the uterus. Invertebrate
Invertebrate
eggs

Nudibranch
Nudibranch
Orange-peel doris
Orange-peel doris
Acanthodoris lutea in tide pool laying eggs

Eggs are common among invertebrates, including insects, spiders, mollusks, and crustaceans. Evolution
Evolution
and structure All sexually reproducing life, including both plants and animals, produces gametes. The male gamete cell, sperm, is usually motile whereas the female gamete cell, the ovum, is generally larger and sessile. The male and female gametes combine to produce the zygote cell. In multicellular organisms the zygote subsequently divides in an organised manner into smaller more specialised cells, so that this new individual develops into an embryo. In most animals the embryo is the sessile initial stage of the individual life cycle, and is followed by the emergence (that is, the hatching) of a motile stage. The zygote or the ovum itself or the sessile organic vessel containing the developing embryo may be called the egg. A recent proposal suggests that the phylotypic animal body plans originated in cell aggregates before the existence of an egg stage of development. Eggs, in this view, were later evolutionary innovations, selected for their role in ensuring genetic uniformity among the cells of incipient multicellular organisms.[15] Scientific classifications Scientists often classify animal reproduction according to the degree of development that occurs before the new individuals are expelled from the adult body, and by the yolk which the egg provides to nourish the embryo. Egg
Egg
size and yolk Vertebrate
Vertebrate
eggs can be classified by the relative amount of yolk. Simple eggs with little yolk are called microlecithal, medium-sized eggs with some yolk are called mesolecithal, and large eggs with a large concentrated yolk are called macrolecithal.[7] This classification of eggs is based on the eggs of chordates, though the basic principle extends to the whole animal kingdom. Microlecithal

Microlecithal eggs from the roundworm Toxocara

Microlecithal eggs from the flatworm Paragonimus westermani

Small eggs with little yolk are called microlecithal. The yolk is evenly distributed, so the cleavage of the egg cell cuts through and divides the egg into cells of fairly similar sizes. In sponges and cnidarians the dividing eggs develop directly into a simple larva, rather like a morula with cilia. In cnidarians, this stage is called the planula, and either develops directly into the adult animals or forms new adult individuals through a process of budding.[16] Microlecithal eggs require minimal yolk mass. Such eggs are found in flatworms, roundworms, annelids, bivalves, echinoderms, the lancelet and in most marine arthropods.[17] In anatomically simple animals, such as cnidarians and flatworms, the fetal development can be quite short, and even microlecithal eggs can undergo direct development. These small eggs can be produced in large numbers. In animals with high egg mortality, microlecithal eggs are the norm, as in bivalves and marine arthropods. However, the latter are more complex anatomically than e.g. flatworms, and the small microlecithal eggs do not allow full development. Instead, the eggs hatch into larvae, which may be markedly different from the adult animal. In placental mammals, where the embryo is nourished by the mother throughout the whole fetal period, the egg is reduced in size to essentially a naked egg cell. Mesolecithal

Frogspawn is mesolecithal.

Mesolecithal eggs have comparatively more yolk than the microlecithal eggs. The yolk is concentrated in one part of the egg (the vegetal pole), with the cell nucleus and most of the cytoplasm in the other (the animal pole). The cell cleavage is uneven, and mainly concentrated in the cytoplasma-rich animal pole.[3] The larger yolk content of the mesolecithal eggs allows for a longer fetal development. Comparatively anatomically simple animals will be able to go through the full development and leave the egg in a form reminiscent of the adult animal. This is the situation found in hagfish and some snails.[4][17] Animals with smaller size eggs or more advanced anatomy will still have a distinct larval stage, though the larva will be basically similar to the adult animal, as in lampreys, coelacanth and the salamanders.[3] Macrolecithal

A baby tortoise begins to emerge "fully developed" from its macrolecithal egg.

Eggs with a large yolk are called macrolecithal. The eggs are usually few in number, and the embryos have enough food to go through full fetal development in most groups.[7] Macrolecithal eggs are only found in selected representatives of two groups: Cephalopods and vertebrates.[7][18] Macrolecithal eggs go through a different type of development than other eggs. Due to the large size of the yolk, the cell division can not split up the yolk mass. The fetus instead develops as a plate-like structure on top of the yolk mass, and only envelopes it at a later stage.[7] A portion of the yolk mass is still present as an external or semi-external yolk sac at hatching in many groups. This form of fetal development is common in bony fish, even though their eggs can be quite small. Despite their macrolecithal structure, the small size of the eggs does not allow for direct development, and the eggs hatch to a larval stage ("fry"). In terrestrial animals with macrolecithal eggs, the large volume to surface ratio necessitates structures to aid in transport of oxygen and carbon dioxide, and for storage of waste products so that the embryo does not suffocate or get poisoned from its own waste while inside the egg, see amniote.[9] In addition to bony fish and cephalopods, macrolecithal eggs are found in cartilaginous fish, reptiles, birds and monotreme mammals.[3] The eggs of the coelacanths can reach a size of 9 cm in diameter, and the young go through full development while in the uterus, living on the copious yolk.[19] Egg-laying reproduction Animals are commonly classified by their manner of reproduction, at the most general level distinguishing egg-laying (Latin. oviparous) from live-bearing (Latin. viviparous). These classifications are divided into more detail according to the development that occurs before the offspring are expelled from the adult's body. Traditionally:[20]

Ovuliparity means the female spawns unfertilized eggs (ova), which must then be externally fertilised. Ovuliparity is typical of bony fish, anurans, echinoderms, bivalves and cnidarians. Most aquatic organisms are ovuliparous. The term is derived from the diminiutive meaning "little egg". Oviparity
Oviparity
is where fertilisation occurs internally and so the eggs laid by the female are zygotes (or newly developing embryos), often with important outer tissues added (for example, in a chicken egg, no part outside of the yolk originates with the zygote). Oviparity
Oviparity
is typical of birds, reptiles, some cartilaginous fish and most arthropods. Terrestrial organisms are typically oviparous, with egg-casings that resist evaporation of moisture. Ovo-viviparity is where the zygote is retained in the adult’s body but there are no trophic (feeding) interactions. That is, the embryo still obtains all of its nutrients from inside the egg. Most live-bearing fish, amphibians or reptiles are actually ovoviviparous. Examples include the reptile Anguis fragilis, the sea horse (where zygotes are retained in the male’s ventral "marsupium"), and the frogs Rhinoderma darwinii (where the eggs develop in the vocal sac) and Rheobatrachus (where the eggs develop in the stomach). Histotrophic viviparity means embryos develop in the female’s oviducts but obtain nutrients by consuming other ova, zygotes or sibling embryos (oophagy or adelphophagy). This intra-uterine cannibalism occurs in some sharks and in the black salamander Salamandra atra. Marsupials
Marsupials
excrete a "uterine milk" supplementing the nourishment from the yolk sak.[21] Hemotrophic viviparity is where nutrients are provided from the female's blood through a designated organ. This most commonly occurs through a placenta, found in most mammals. Similar structures are found in some sharks and in the lizard Pseudomoia pagenstecheri.[22][23] In some hylid frogs, the embryo is fed by the mother through specialized gills.[24]

The term hemotropic derives from the Latin for blood-feeding, contrasted with histotrophic for tissue-feeding.[25] Human use Food Main article: Egg
Egg
(food) Eggs laid by many different species, including birds, reptiles, amphibians, and fish, have probably been eaten by mankind for millennia. Popular choices for egg consumption are chicken, duck, roe, and caviar, but by a wide margin the egg most often humanly consumed is the chicken egg, typically unfertilized. Eggs and Kashrut See also: Kashrut
Kashrut
§ Pareve foods, and Kosher
Kosher
foods § Eggs According to the Kashrut, that is the set of Jewish dietary laws, kosher food may be consumed according to halakha (Jewish law). Kosher meat and milk (or derivatives) cannot be mixed (Deuteronomy 14:21) or stored together. Eggs are considered pareve (neither meat nor dairy) despite being an animal product and can be mixed with either milk or kosher meat. Mayonnaise, for instance, is usually marked "pareve" despite by definition containing egg.[26] Vaccine manufacture Many vaccines for infectious diseases are produced in fertile chicken eggs. The basis of this technology was the discovery in 1931 by Alice Miles Woodruff and Ernest William Goodpasture
Ernest William Goodpasture
at Vanderbilt University that the rickettsia and viruses that cause a variety of diseases will grow in chicken embryos. This enabled the development of vaccines against influenza, chicken pox, smallpox, yellow fever, typhus, Rocky mountain spotted fever and other diseases. Culture The egg is a symbol of new life and rebirth in many cultures around the world. Christians view Easter egg
Easter egg
as a symbolic of the resurrection of Jesus Christ. [27] A popular Easter tradition in some parts of the world is the decoration of hard-boiled eggs (usually by dyeing, but often by spray-painting). Adults often hide the eggs for children to find, an activity known as an Easter egg
Easter egg
hunt. A similar tradition of egg painting exists in areas of the world influenced by the culture of Persia. Before the spring equinox in the Persian New Year tradition (called Norouz), each family member decorates a hard-boiled egg and sets them together in a bowl. The tradition of a dancing egg is held during the feast of Corpus Christi in Barcelona and other Catalan cities since the 16th century. It consists of an emptied egg, positioned over the water jet from a fountain, which starts turning without falling.[28] Although being a food item, eggs are sometimes thrown at houses, cars, or people. This act, known commonly as "egging" in the various English-speaking countries, is a minor form of vandalism and, therefore, usually a criminal offense and is capable of damaging property (egg whites can degrade certain types of vehicle paint) as well as causing serious eye injury. On Halloween, for example, trick or treaters have been known to throw eggs (and sometimes flour) at property or people from whom they received nothing. Eggs are also often thrown in protests, as they are inexpensive and nonlethal, yet very messy when broken. [29] Collecting Egg
Egg
collecting was once a popular hobby. White settlers favored this practice when they first came to Australia. Traditionally, the embryo would be removed before a collector stored the egg shell. [30] Collecting eggs of wild birds is now banned by many countries and regions in consideration of the threaten to rare species. In the United Kingdom, Protection of Birds
Birds
Act 1954 and Wildlife and Countryside Act 1981 both state that if a person intentionally takes or destroys an egg of any wild bird, he shall be considered guilty and penalized. [31] On the other hand, ongoing underground trading is becoming a serious issue. In the documentary film Poached (2015) [32], director Timothy Wheeler got the opportunity to work with the U.K.’s Royal Society for the Protection of Birds
Birds
(RSPB) and the country’s National Wildlife Crime Unit, and delved into the motivation behind egg-collecting criminals. [33] Since the protection of wild bird eggs was regulated, early collections have come to the museums as curiosities. For example, the Australian Museum hosts a collection of about 20,000 registered clutches of eggs, [34] and the collection in Western Australia Museum has been archived in a gallery.[35] Scientists regard egg collections as a good natural-history data, the details recorded in the collectors' notes have helped them to understand birds' nesting behaviors. [36] Gallery

Insect
Insect
eggs, in this case those of the Emperor gum moth, are often laid on the underside of leaves.

Fish
Fish
eggs, such as these herring eggs are often transparent and fertilized after laying.

Skates and some sharks have a uniquely shaped egg case called a mermaid's purse.

A Testudo hermanni
Testudo hermanni
emerging fully developed from a reptilian egg.

A Schistosoma mekongi
Schistosoma mekongi
egg.

Eggs of Huffmanela hamo, a nematode parasite in a fish

Eggs of various parasites (mainly nematodes) from wild primates

See also

List of egg topics Animal
Animal
shell Butterfly eggs Egg
Egg
(food) Egg yolk
Egg yolk
and Egg
Egg
white Fossil egg Haugh unit Oology Ovary Ovulation Oviparous Trophic egg

References

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Vertebrate
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Hagfish
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specimens - Australian Museum". australianmuseum.net.au. Retrieved 2018-03-31.  ^ "Explore our Egg
Egg
Collection Western Australian Museum". Western Australian Museum. Retrieved 2018-03-31.  ^ Golembiewski, Kate. "The Lost Victorian Art of Egg
Egg
Collecting". The Atlantic. Retrieved 2018-03-31. 

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Eggs

List of egg topics

Types

Bird Fish
Fish
and amphibian Monotreme

Fossil record

Cephalopod Fish Reptile
Reptile
(dinosaur) Pathology

Biology

Embryo Ichthyoplankton Ootheca Oviparity Spawn Zygote

Components

Yolk White Shell

As food

List of egg dishes Boiled Coddled Custard desserts Deviled Eggs Benedict Fried Omelette Poached Pickled Roe Scotch Scrambled Smoked Soufflé Tea egg Trophic egg

In culture

Easter egg Egging Fabergé egg Humpty Dumpty Oomancy Ovo vegetarianism Yoshi

Category Commons

v t e

Birds
Birds
(class: Aves)

Anatomy

Bird
Bird
anatomy Flight Eggs Feathers Plumage Beak Vision Dactyly Preen gland

Behaviour

Singing Intelligence Migration Sexual selection Lek mating Seabird
Seabird
breeding Incubation Brood parasites Nesting Hybrids

Evolution

Origin of birds Origin of flight Evolution
Evolution
of birds Darwin's finches Seabirds

Fossil birds

Archaeopteryx Omnivoropterygiformes Confuciusornithiformes Enantiornithes Chaoyangiiformes Patagopterygiformes Ambiortiformes Songlingornithiformes Apsaraviformes Gansuiformes Ichthyornithiformes Hesperornithes Lithornithiformes Dinornithiformes Aepyornithiformes Gastornithiformes

Human interaction

Ringing Ornithology Bird
Bird
collections Birdwatching Bird
Bird
feeding Conservation Aviculture Waterfowl hunting Cockfighting Pigeon
Pigeon
racing Falconry Pheasantry Egg
Egg
collecting Ornithomancy

Lists

Families and orders Genera Glossary of bird terms List by population Lists by region Recently extinct birds Late Quaternary prehistoric birds Notable birds

Individuals Fictional

Neornithes

Palaeognathae

Struthioniformes (ostriches) Rheiformes (rheas) Tinamiformes (tinamous) Apterygiformes (kiwis) Casuariiformes
Casuariiformes
(emus and cassowaries)

Neognathae

Galloanserae (fowls)

Anseriformes (waterfowls)

Anatidae (ducks)

Anatinae Anserinae

swans true geese

Aythyinae Dendrocygninae Merginae Oxyurinae Plectropterinae Stictonettinae Tadorninae Thalassorninae

Anhimidae

Anhima Chauna

Anseranatidae

Anatalavis Anseranas

Galliformes (landfowls- gamebirds)

Cracidae

Cracinae Oreophasinae Penelopinae

Megapodidae

Aepypodius Alectura Eulipoa Leipoa Macrocephalon Megapodius Talegalla

Numididae

Acryllium Agelastes Guttera Numida

Odontophoridae

Callipepla Colinus Cyrtonyx Dactylortyx Dendrortyx Odontophorus Oreortyx Philortyx Rhynchortyx

Phasianidae

Meleagridinae Perdicinae Phasianinae
Phasianinae
(pheasants and relatives) Tetraoninae

Neoaves

Columbea

Columbimorphae

Columbiformes
Columbiformes
(doves and pigeons) Mesitornithiformes (mesites) Pteroclidiformes (sandgrouses)

Mirandornithes

Phoenicopteriformes (flamingos) Podicipediformes (grebes)

Passerea

Otidimorphae

Cuculiformes (cuckoos) Musophagiformes (turacos) Otidiformes (bustards)

Strisores

Caprimulgiformes
Caprimulgiformes
(nightjars and relatives) Steatornithiformes Podargiformes Apodiformes
Apodiformes
(swifts and hummingbirds)

Opisthocomiformes

Opisthocomiformes
Opisthocomiformes
(hoatzin)

Cursorimorphae

Charadriiformes
Charadriiformes
(gulls and relatives) Gruiformes
Gruiformes
(cranes and relatives)

Phaethontimorphae

Phaethontiformes (tropicbirds) Eurypygiformes
Eurypygiformes
(kagu and sunbittern)

Aequornithes

Gaviiformes (loons or divers) Sphenisciformes (penguins) Procellariiformes
Procellariiformes
(albatrosses and petrels) Ciconiiformes
Ciconiiformes
(storks) Suliformes
Suliformes
(cormorants and relatives) Pelecaniformes
Pelecaniformes
(pelicans and relatives)

Australaves

Cariamiformes
Cariamiformes
(seriemas and relatives) Falconiformes (falcons and relatives) Psittaciformes (parrots) Passeriformes (perching birds)

Afroaves

Cathartiformes
Cathartiformes
(New World vultures and condors) Accipitriformes
Accipitriformes
(eagles and hawks) Strigiformes (owls) Coliiformes (mousebirds) Trogoniformes (trogons and quetzals) Leptosomatiformes (cuckoo roller) Bucerotiformes
Bucerotiformes
(hornbills and hoopoes) Coraciiformes
Coraciiformes
(kingfishers and rollers) Piciformes
Piciformes
(woodpeckers and relatives)

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