Red Kite (Milvus milvus) in flight, showing remiges and rectrices

Flight feathers are the long, stiff, asymmetrically shaped, but symmetrically paired feathers on the wings or tail of a bird; those on the wings are called remiges (singular remex) while those on the tail are called rectrices (singular rectrix). Their primary function is to aid in the generation of both thrust and lift, thereby enabling flight. The flight feathers of some birds have evolved to perform additional functions, generally associated with territorial displays, courtship rituals or feeding methods. In some species, these feathers have developed into long showy plumes used in visual courtship displays, while in others they create a sound during display flights. Tiny serrations on the leading edge of their remiges help owls to fly silently (and therefore hunt more successfully), while the extra-stiff rectrices of woodpeckers help them to brace against tree trunks as they hammer. Even flightless birds still retain flight feathers, though sometimes in radically modified forms. Image File history File links Metadata Size of this preview: 450 × 600 pixelsFull resolution (600 × 800 pixel, file size: 130 KB, MIME type: image/jpeg) Gwelir Barcud Coch yn hedfan Source own work Date 2006-03-23 Author Thomas Kraft (ThKraft) Permission (Reusing this image) Other versions File historyClick on... Image File history File links Metadata Size of this preview: 450 × 600 pixelsFull resolution (600 × 800 pixel, file size: 130 KB, MIME type: image/jpeg) Gwelir Barcud Coch yn hedfan Source own work Date 2006-03-23 Author Thomas Kraft (ThKraft) Permission (Reusing this image) Other versions File historyClick on... Binomial name Milvus milvus Linnaeus, 1758 The Red Kite (Milvus milvus) is a medium-large bird of prey in the family Accipitridae, which also includes many other diurnal raptors such as eagles, buzzards and harriers. ... Two feathers Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds. ... For other uses, see Wing (disambiguation). ... A scorpion tail The tail is the section at the rear end of an animals body; in general, the term refers to a distinct, flexible appendage to the torso. ... For other uses, see Bird (disambiguation). ... Thrust is a reaction force described quantitatively by Newtons Second and Third Laws. ... The force lift, or simply lift, is a mechanical force generated by solid objects as they move through a fluid. ... Flight is the main mode of locomotion used by most of the worlds bird species. ... For other uses, see Owl (disambiguation). ... Genera Melanerpes Sphyrapicus Xiphidiopicus Dendropicos Dendrocopos Picoides Veniliornis Campethera Geocolaptes Dinopium Meiglyptes Hemicircus Micropternus Picus Mulleripicus Dryocopus Celeus Piculus Colaptes Campephilus Chrysocolaptes Reinwardtipicus Blythipicus Gecinulus Sapheopipo For other uses, see Woodpecker (disambiguation). ...

The moult of their flight feathers can cause serious problems for birds, as it can impair their ability to fly. Different species have evolved different strategies for coping with this, ranging from dropping all their flight feathers at once (and thus becoming flightless for some relatively short period of time) to extending the moult over a period of several years.

Remiges

Bird wing bone structure, indicating attachment points of remiges

Remiges (from the Latin for "oarsman") are located on the posterior side of the wing. Ligaments attach the long calami, or quills, firmly to the wing bones, and a thick, strong band of tendinous tissue—known as the postpatagium—helps to hold and support the remiges in place.^[1] Corresponding remiges on individual birds are symmetrical between the two wings, matching to a large extent in size and shape (except in the case of mutation or damage), though not necessarily in pattern.^[2][3] They are given different names depending on their position along the wing. The English word POSTERIOR is identical to the original Latin adjective, and has two different uses : as an ADJECTIVE, it indicates that someone or something is behind another, either spatially or chronologically it also became a SUBSTANTIVE, indicating the rear-end, especially of a person, i. ... In anatomy, the term ligament is used to denote three different types of structures:[1] Fibrous tissue that connects bones to other bones. ... This article is about the skeletal organs. ... A tendon (or sinew) is a tough band of fibrous connective tissue that connects muscle to bone and is built to withstand tension. ... Sphere symmetry group o. ... For linguistic mutation, see Apophony. ...

Primaries

Primaries are connected to the manus (the bird's "hand", composed of carpometacarpus and phalanges); these are the longest and narrowest of the remiges (particularly those attached to the phalanges), and they can be individually rotated. These feathers are especially important for flapping flight, as they are the principal source of thrust, moving the bird forward through the air. Most thrust is generated on the downstroke of flapping flight. However, on the upstroke (when the bird often draws its wing in close to its body), the primaries are separated and rotated, reducing air resistance while still helping to provide some thrust.^[4] The flexibility of the remiges on the wingtips of large soaring birds also allows for the spreading of those feathers, which helps to reduce the creation of wingtip vortices, thereby reducing drag.^[5] This principle has been applied to aircraft wings, designers noting inspiration from the harrier hawk though splayed vortex reducers are less common than other wingtip devices. The manus (Latin for hand) is the zoological term for the distal portion of the fore limb of an animal. ... The phalanges in a human hand The name Phalanges is commonly given to the bones that form fingers and toes. ... Thrust is a reaction force described quantitatively by Newtons Second and Third Laws. ... Vortex created by the passage of an aircraft wing, revealed by coloured smoke A vortex (pl. ... In physics, the drag equation gives the drag experienced by an object moving through a fluid. ... Binomial name Circus aeruginosus (Linnaeus, 1758) Circus spilonotus Kaup, 1847 Circus approximans Peale, 1848 The Marsh Harriers are birds of prey of the harrier subfamily. ... Rutan VariEze, the first aircraft to use winglets in 1975 Learjet 28/29, the first production jet aircraft to use winglets in 1977 McDonnell Douglas MD-11, one of the first airliners to benefit from winglet research Wingtip devices are usually intended to improve the efficiency of fixed-wing aircraft. ...

Bald Eagle (Haliaeetus leucocephalus) in flight with primaries spread to decrease drag and improve lift

Species vary somewhat in the number of primaries they possess. The number in non-passerines generally varies between 9 and 11,^[6] but grebes, storks and flamingos have 12,^[7] and ostriches have 16.^[7] While most modern passerines have ten primaries,^[6] some have only nine. Those with nine are missing the most distal primary (sometimes called the remicle) which is typically very small and sometimes rudimentary in passerines.^[7] Binomial name (Linnaeus, 1766) Bald Eagle range  Resident, breeding Summer visitor, breeding Winter visitor On migration only Star: accidental records Subspecies (Linnaeus, 1766) Southern Bald Eagle (Audubon, 1827) Northern Bald Eagle Synonyms Falco leucocephalus Linnaeus, 1766 The Bald Eagle (Haliaeetus leucocephalus) is a bird of prey found in North America... Flight is the main mode of locomotion used by most of the worlds bird species. ... Genera Podiceps Tachybaptus Podilymbus Aechmophorus Poliocephalus Rollandia Grebes are members of the Podicipediformes order, a widely distributed order of freshwater diving birds, some of which visit the sea when migrating and in winter. ... For other uses, see Stork (disambiguation). ... Species See text For other uses, see Flamingo (disambiguation). ... Binomial name Linnaeus, 1758 The present-day distribution of Ostriches. ... Families Many, see text A passerine is a bird of the giant order Passeriformes. ...

The outermost primaries—those connected to the phalanges—are sometimes known as pinions.

Secondaries

Primary (left) and secondary (right) feathers of the Common Buzzard (Buteo buteo); note the asymmetrical orientation of the shafts

Secondaries are connected to the ulna. In some species, the ligaments that bind these remiges to the bone connect to small, rounded projections, known as quill knobs, on the ulna; in other species, no such knobs exist. Secondary feathers remain close together in flight (they cannot be individually separated like the primaries can) and help to provide lift by creating the airfoil shape of the bird's wing. Secondaries tend to be shorter and broader than primaries, with blunter ends (see illustration). They vary in number from 6 in hummingbirds to as many as 40 in some species of albatross.^[8] In general, larger and longer-winged species have a larger number of secondaries.^[8] Birds in more than 40 non-passerine families seem to be missing the fifth secondary feather on each wing, a state known as diastataxis.^[9] In these birds, the fifth set of secondary covert feathers does not cover any remex, possibly due to a twisting of the feather papillae during embryonic development.^[9] Loons, grebes, pelicans, hawks and eagles, cranes, sandpipers, gulls, parrots, and owls are among the families missing this feather. Image File history File linksMetadata No higher resolution available. ... Image File history File linksMetadata No higher resolution available. ... Binomial name Buteo buteo (Linnaeus, 1758) The Common Buzzard (Buteo buteo) is a bird of prey from the Old World. ... The ulna (Elbow Bone) [Figs. ... For other uses, see Hummingbird (disambiguation). ... This article is about the bird family. ... For other uses, see Embryo (disambiguation). ... Global distribution of Gaviidae (breeding and winter ranges combined) Species Gavia stellata Gavia arctica Gavia pacifica Gavia immer Gavia adamsii The Loons (N.Am. ... Genera Podiceps Tachybaptus Podilymbus Aechmophorus Poliocephalus Rollandia Grebes are members of the Podicipediformes order, a widely distributed order of freshwater diving birds, some of which visit the sea when migrating and in winter. ... For other uses, see Pelican (disambiguation). ... Genera Accipiter Micronisus Melierax Urotriorchis Erythrotriorchis The term hawk refers to birds of prey in any of three senses: Strictly, to mean any of the species in the bird sub-family Accipitrinae in the genera Accipiter, Micronisus, Melierax, Urotriorchis, and Megatriorchis. ... Eagles redirects here. ... Genera Grus Anthropoides Balearica Bugeranus Cranes are large, long-legged and long-necked birds of the order Gruiformes, and family Gruidae. ... Families Charadridae Jacanidae Rostratulidae Ibidorhynchidae Recurvirostridae Haematopodidae Scolopacidae Dromadidae Burhinidae Glareolidae Thinocoridae Waders, called Shorebirds in North America (where wader is used to refer to long-legged wading birds such as storks and herons), are members of the order Charadriiformes, excluding the more marine web-footed seabird groups. ... “Seagull” redirects here. ... Systematics (but see below) Family Cacatuidae (cockatoos) Subfamily Microglossinae (Palm Cockatoo) Subfamily Calyptorhynchinae (dark cockatoos) Subfamily Cacatuinae (white cockatoos) Family Psittacidae (true parrots) Subfamily Loriinae (lories and lorikeets) Subfamily Psittacinae (typical parrots and allies) Tribe Arini (American psittacines) Tribe Cyclopsitticini (fig parrots) Tribe Micropsittini (pygmy parrots) Tribe Nestorini (kakas and... For other uses, see Owl (disambiguation). ...

Tertials

Tertials are connected to the humerus in some species. These elongated "true" tertials act as a protective cover for all or part of the folded primaries and secondaries, and do not qualify as flight feathers as such.^[10] However, many authorities use the term tertials to refer to the shorter, more symmetrical innermost secondaries of passerines (which perform the same function as true tertials) in an effort to distinguish them from the other secondaries. The humerus is a long bone in the arm or fore-legs (animals) that runs from the shoulder to the elbow. ...

Emargination

The outermost primaries of large soaring birds, particularly raptors, often show a pronounced narrowing at some variable distance along the feather edges. These narrowings are called either notches or emarginations depending on the degree of their slope.^[9] An emargination is a gradual change, and can be found on either side of the feather. A notch is an abrupt change, and is only found on the wider trailing edge of the remige. (Both are visible on the primary in the photo showing the feathers; they can be found about halfway along both sides of the left hand feather—a shallow notch on the left, and a gradual emargination on the right.) The presence of notches and emarginations creates gaps at the wingtip; air is forced through these gaps, increasing the generation of lift.^[11]

Alula

Male Mallard (Anas platyrhynchus) landing, showing outspread alula

Feathers on the alula or bastard wing are not generally considered to be flight feathers in the strict sense; though they are asymmetrical, they lack the length and stiffness of most true flight feathers. However, alula feathers are definitely an aid to slow flight. These feathers—which are attached to the bird's "thumb" and normally lie flush against the anterior edge of the wing—function in the same way as the slats on an airplane wing, allowing the wing to achieve a higher than normal angle of attack – and thus lift – without resulting in a stall. By manipulating its thumb to create a gap between the alula and the rest of the wing, a bird can avoid stalling when flying at low speeds or landing.^[9] For other uses, see Mallard (disambiguation). ... The alula, or bastard wing, is a small, feathered projection on the anterior edge of the wing of modern birds. ... The alula, or bastard wing, is a small, feathered projection on the anterior edge of the wing of modern birds. ... In zootomy, several terms are used to describe the location of organs and other structures in the body of bilateral animals. ... Slats are small aerodynamic surfaces on the leading edge of an airplane wing which, when deployed, allow the wing to operate at a higher angle of attack. ... In this diagram, the black arrow represents the direction of the wind. ... The force lift, or simply lift, is a mechanical force generated by solid objects as they move through a fluid. ... In aerodynamics, a stall is a condition in which an excessive angle of attack causes loss of lift due to disruption of airflow. ...

Delayed development in Hoatzins

The development of the remiges (and alula) of nestling Hoatzins is much delayed compared to the development of these feathers in other young birds, presumably because young Hoatzins are equipped with claws on their first two digits. They use these small rounded hooks to grasp branches when clambering about in trees, and feathering on these digits would presumably interfere with that functionality. Most youngsters shed their claws sometime between their 70^th and 100^th day of life, but some retain them—though callused-over and unusable—into adulthood.^[12][13] Binomial name Ophisthocomus hoazin (Muller, 1776) The Hoatzin (Opisthocomus hoazin) is an odd species of tropical bird which is found in the swamps associated with the Amazon and Orinoco rivers of South America. ... Cat claw A claw is a curved pointed appendage, found at the end of a toe or finger or, in arthropods, of the tarsus. ... This article does not cite any references or sources. ... This article is about calluses and corns of human skin. ...

Rectrices

Rectrices (from the Latin for "helmsman"), which help the bird to brake and steer in flight, lie in a single horizontal row on the rear margin of the anatomical tail. Only the central pair are attached (via ligaments) to the tail bones; the remaining rectrices are embedded into the rectricial bulbs, complex structures of fat and muscle that surround those bones. Rectrices are always paired, with a vast majority of species having six pairs. They are absent in grebes and some ratites, and greatly reduced in size in penguins.^{[7][14][15][16]} Many grouse species have more than 12 rectrices; some (including Ruffed Grouse and Hazel Grouse) have a number that varies between individuals.^[17] Domestic pigeons have a highly variable number, due to centuries of selective breeding.^[18] In anatomy, the term ligament is used to denote three different types of structures:[1] Fibrous tissue that connects bones to other bones. ... This article is about the skeletal organs. ... Families Struthionidae (ostriches) Rheidae (rheas) Casuariidae (emus etc. ... Modern genera Aptenodytes Eudyptes Eudyptula Megadyptes Pygoscelis Spheniscus For prehistoric genera, see Systematics Some penguins are curious. ... Genera Tetrao Lagopus Falcipennis Centrocercus Bonasa Dendrapagus Tympanuchus Grouse are from the order Galliformes which inhabit temperate and subarctic regions of the northern hemisphere. ... Binomial name (Linnaeus, 1766) The Ruffed Grouse, Bonasa umbellus, is a medium-sized grouse occurring in forests across Canada and the Appalachian and northern United States including Alaska. ... Binomial name Bonasa bonasia (Linnaeus, 1758) The Hazel Grouse (Bonasa bonasia) is a large bird in the grouse family. ... Binomial name Columba livia Gmelin, 1789 The Rock Pigeon (Columba livia), is a member of the bird family Columbidae, doves and pigeons. ...

Numbering conventions

In order to make the discussion of such topics as moult processes or body structure easier, ornithologists assign a number to each flight feather. By convention, the numbers assigned to primary feathers always start with the letter P (P1, P2, P3, etc.), those of secondaries with the letter S, those of tertials with T and those of rectrices with R. In animals, moulting (Commonwealth English) or molting (American English) is the routine shedding off old feathers in birds, or of old skin in reptiles, or of old hairs in mammals (see also coat (dog)). In arthropods, such as insects, arachnids and crustaceans, moulting describes the shedding of its exoskeleton (which... With regard to living things, a body is the integral physical material of an individual. ... Ornithology (from the Greek ornitha = chicken and logos = word/science) is the branch of biology concerned with the scientific study of birds. ... For other uses, see Number (disambiguation). ...

Most authorities number the primaries descendantly, starting from the innermost primary (the one closest to the secondaries) and working outwards; others number them ascendantly, from the most distal primary inwards.^[6] There are some advantages to each method. Descendant numbering follows the normal sequence of most birds' primary moult. In addition, in the event that a species is missing the small distal 10^th primary, as some passerines are, its lack does not impact the numbering of the remaining primaries. Ascendant numbering, on the other hand, allows for uniformity in the numbering of non-passerine primaries, as they almost invariably have four attached to the manus regardless of how many primaries they have overall. ^[6] This method is particularly useful for indicating wing formulae, as the outermost primary is the one with which the measurements begin.

Secondaries are always numbered ascendantly, starting with the outermost secondary (the one closest to the primaries) and working inwards.^[6] Tertials are also numbered ascendantly, but in this case, the numbers continue on consecutively from that given to the last secondary (e.g. … S5, S6, T7, T8, … etc.).^[6]

Rectrices are always numbered from the centermost pair outwards in both directions.^[19]

Specialized flight feathers

Male Pin-tailed Whydah (Vidua macroura) showing modified rectrices

The flight feathers of some species have undergone evolutionary changes which allow them to provide additional functionality. Binomial name Vidua macroura (Pallas, 1764) The Pin-tailed Whydah, Vidua macroura, is a small songbird. ...

In some species, for example, either remiges or rectrices make a sound during flight. These sounds are most often associated with courtship or territorial displays. The outer primaries of male Broad-tailed Hummingbirds produce a distinctive high-pitched trill, both in direct flight and in power-dives during courtship displays; this trill is diminished when the outer primaries are worn, and absent when those feathers have been moulted.^[20] During the Northern Lapwing's zigzagging display flight, the bird's outer primaries produce a humming sound.^[21] The outer primaries of the male American Woodcock are shorter and slightly narrower than those of the female, and are likely the source of the whistling and twittering sounds made during his courtship display flights.^[22] Male Club-winged Manakins use modified secondaries to make a clear trilling courtship call. A curve-tipped secondary on each wing is dragged against an adjacent ridged secondary at high speeds (as many as 100 times per second—twice as fast as a hummingbird's wingbeat) to create a stridulation much like that produced by some insects.^[23] Both Wilson's and Common Snipe have modified outer tail feathers which make noise when they are spread during the birds' roller coaster display flights; as the bird dives, wind flows through the modified feathers and creates a series of rising and falling notes, which is known as "winnowing".^[24] Differences between the sounds produced by these two former conspecific subspecies—and the fact that the outer two pairs of rectrices in Wilson's Snipe are modified, while only the single outermost pair are modified in Common Snipe—were among the characteristics used to justify their splitting into two distinct and separate species. This article is about the Male sex. ... Binomial name Selasphorus platycercus (Swainson, 1827) The broad-tailed hummingbird, Selasphorus platycercus, is a medium-sized hummingbird, nearly four inches in length. ... Binomial name Vanellus vanellus (Linnaeus, 1758) The Northern Lapwing (Vanellus vanellus), also known as the Peewit or just Lapwing, is a bird in the plover family. ... Binomial name Scolopax minor Gmelin, 1789 The American Woodcock, Scolopax minor, is a small chunky shorebird. ... Binomial name Machaeropterus deliciosus (Sclater, 1852) The Club-winged Manakin, Machaeropterus deliciosus is a small passerine bird which is a resident breeding species in the cloud forest on the western slopes of the Andes Mountains of Colombia and northwestern Ecuador. ... Stridulation is the act of producing sound by rubbing together certain body parts. ... Binomial name Gallinago gallinago Linnaeus, 1758 Subspecies (Wilsons Snipe) The Common Snipe, Gallinago gallinago, is a small, stocky shorebird. ... Binomial name Gallinago gallinago Linnaeus, 1758 Subspecies The Common Snipe (Gallinago gallinago) is a small, stocky shorebird. ...

Flight feathers are also used by some species in visual displays. Male Standard-winged and Pennant-winged Nightjars have modified P2 primaries (using the descendant numbering scheme explained above) which are displayed during their courtship rituals.^[25] In the Standard-winged Nightjar, this modified primary consists of an extremely long shaft with a small "pennant" (actually a large web of barbules) at the tip. In the Pennant-winged Nightjar, the P2 primary is an extremely long (but otherwise normal) feather, while P3, P4 and P5 are successively shorter; the overall effect is a broadly-forked wingtip with a very long plume beyond the lower half of the fork. Binomial name Macrodipteryx longipennis (Shaw, 1796) The Standard-winged Nightjar, Macrodipteryx longipennis, is a bird in the nightjar family. ... Binomial name (Gould, 1838) The Pennant-winged Nightjar is an intra African migrant that occurs from Nigeria to northern South Africa. ...

Leading edge of an owl feather, showing serrations

Males of many species, ranging from the widely introduced Ring-necked Pheasant to Africa's many whydahs, have one or more elongated pairs of rectrices, which play an often-critical role in their courtship rituals. The outermost pair of rectrices in male lyrebirds are extremely long and strongly curved at the ends. These plumes are raised up over the bird's head (along with a fine spray of modified uppertail coverts) during his extraordinary display. Rectrix modification reaches its pinnacle among the birds of paradise, which display an assortment of often bizarrely modified feathers, ranging from the extremely long plumes of the Ribbon-tailed Astrapia (nearly three times the length of the bird itself) to the dramatically coiled twin plumes of the Magnificent Bird of Paradise. Binomial name Phasianus colchicus Linnaeus, 1758 The Common Pheasant (Phasianus colchicus) is a gamebird in the pheasant family Phasianidae of the order Galliformes, gallinaceous birds. ... A world map showing the continent of Africa Africa is the worlds second-largest and second most-populous continent, after Asia. ... Genus Vidua For the pirate ship Whydah, see Whydah Gally The Indigobirds and whydahs, are small passerine birds native to Africa. ... Species Menura novaehollandiae Menura alberti A Lyrebird is either of two species of ground-dwelling Australian birds, most notable for their extraordinary ability to mimic natural and artificial sounds from their environment. ... For the flowering plant of this name, see Strelitzia Genera Cicinnurus Diphyllodes Epimachus Lophorina Manucodia Paradisaea Parotia Ptiloris Seleucidis Lesser Bird of Paradise Paradisaea minor (c)Roderick Eime The birds of paradise are members of the family Paradisaeidae of the order Passeriformes, found in Oceania. ... Binomial name Astrapia mayeri Stonor, 1939 The Ribbon-tailed Astrapia, Astrapia mayeri is a medium-sized, up to 32cm long, velvet black bird of paradise. ... Binomial name Cicinnurus magnificus Pennant, 1781 The Magnificent Bird of Paradise, Cicinnurus magnificus is a small, up to 26cm long, bird of paradise with an extremely complex plumages. ...

Owls have remiges which are serrated rather than smooth on the leading edge. This adaptation disrupts the flow of air over the wings, eliminating the noise that airflow over a smooth surface normally creates, and allowing the birds to fly silently.^[26] For other uses, see Owl (disambiguation). ...

The rectrices of woodpeckers are proportionately short and very stiff, allowing them to better brace themselves against tree trunks while feeding. This adaptation is also found, though to a lesser extent, in some other species that feed along tree trunks, including woodcreepers and treecreepers. Genera Melanerpes Sphyrapicus Xiphidiopicus Dendropicos Dendrocopos Picoides Veniliornis Campethera Geocolaptes Dinopium Meiglyptes Hemicircus Micropternus Picus Mulleripicus Dryocopus Celeus Piculus Colaptes Campephilus Chrysocolaptes Reinwardtipicus Blythipicus Gecinulus Sapheopipo For other uses, see Woodpecker (disambiguation). ... Genera Dendrocincla Sittasomus Glyphorynchus Drymornis Nasica Dendrexetastes Hylexetastes Xiphocolaptes Dendrocolaptes Xiphorhynchus Lepidocolaptes Campylorhamphus The woodcreepers are a family of passerine bird species endemic to the neotropics. ... genera Certhia Salpornis The treecreepers (Certhiidae) are a family of small passerine birds, consisting of two subfamilies: The typical treecreepers (Certhiinae) are a group of seven species found in Europe and Asia, with one representative, the Brown Creeper, in North America. ...

Scientists have not yet determined the function of all flight feather modifications. For instance, male swallows in the genera Psalidoprocne and Stelgidopteryx have tiny recurved hooks on the leading edges of their outer primaries, but the function of these hooks is not yet known; some authorities suggest they may produce a sound during territorial or courtship displays.^[27]

Vestigiality in flightless birds

Double-wattled Cassowary, (Casuarius casuarius) showing modified remiges

Over time, a small number of bird species have lost their ability to fly. Some of these, such as the flightless steamer ducks, show no appreciable changes in their flight feathers. Some, such as the Titicaca Flightless Grebe and a number of the flightless rails, have a reduced number of primaries.^[28] Image File history File links Download high-resolution version (1263x1134, 308 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Southern Cassowary ... Image File history File links Download high-resolution version (1263x1134, 308 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Southern Cassowary ... Binomial name Casuarius casuarius Linnaeus, 1758 Distribution of the Southern Cassowary The Southern Cassowary (Casuarius casuarius), also known as Double-wattled Cassowary or Two-wattled Cassowary, is a large flightless black bird with hard and stiff plumage, a brown casque, blue face and neck, red nape and two red wattles... Species Tachyeres patachonicus (Flying Steamer Duck) Tachyeres pteneres (Magellanic Flightless Steamer Duck) Tachyeres brachypterus (Falkland Flightless Steamer Duck) Tachyeres leucocephalus (White-headed Flightless Steamer Duck) Tachyeres (Steamer Ducks) is a genus of ducks in the bird family Anatidae. ... Binomial name Rollandia microptera (Gould, 1868) The Titicaca Flightless Grebe Rollandia microptera is a grebe found on freshwater lakes on the altiplano of Peru and Bolivia, including Lake Titicaca. ...

The remiges of ratites are soft and downy; they lack the interlocking hooks and barbules that help to stiffen the flight feathers of other birds. In addition, the Emu's remiges are proportionately much reduced in size, while those of the cassowaries are reduced both in number and structure, consisting merely of 5–6 bare quills. Most ratites have completely lost their rectrices; only the Ostrich still has them. For other uses, see EMU. Binomial name (Latham, 1790) The Emu has been recorded in the areas shown in orange. ... Species Casuarius casuarius Casuarius unappendiculatus Casuarius bennetti Cassowaries (genus Casuarius) are very large flightless birds native to the tropical forests of New Guinea and northeastern Australia. ...

Penguins have lost their differentiated flight feathers. As adults, their wings and tail are covered with the same small, stiff, slightly curved feathers as are found on the rest of their bodies. This article is about penguin birds. ...

The ground-dwelling Kakapo, which is the world's only flightless parrot, has remiges which are shorter, rounder and more symmetrically vaned than those of parrots capable of flight; these flight feathers also contain fewer interlocking barbules near their tips.^[29] Binomial name Gray, 1845 The Kakapo (Māori: kākāpō, meaning night parrot), Strigops habroptilus (from the Greek strix, genitive strigos: owl and ops: face; and habros: soft, and ptilon: feather), also called owl parrot, is a species of nocturnal parrot with finely blotched yellow-green plumage endemic to... Systematics (but see below) Family Cacatuidae (cockatoos) Subfamily Microglossinae (Palm Cockatoo) Subfamily Calyptorhynchinae (dark cockatoos) Subfamily Cacatuinae (white cockatoos) Family Psittacidae (true parrots) Subfamily Loriinae (lories and lorikeets) Subfamily Psittacinae (typical parrots and allies) Tribe Arini (American psittacines) Tribe Cyclopsitticini (fig parrots) Tribe Micropsittini (pygmy parrots) Tribe Nestorini (kakas and...

Moult

Eurasian Jackdaw (Corvus monedula), showing moult of central rectrices

Once they have finished growing, feathers are essentially dead structures. Over time, they become worn and abraded, and need to be replaced. This replacement process is known as moult (molt in the United States). The loss of wing and tail feathers can affect a bird's ability to fly (sometimes dramatically) and in certain families can impair the ability to feed or perform courtship displays. The timing and progression of flight feather moult therefore varies between families. Binomial name Corvus monedula (Linnaeus, 1758) The Jackdaw (Corvus monedula) is one of the smallest species (34-39 cm in length) in the genus of crows and ravens. ... In animals, moulting (Commonwealth English) or molting (American English) is the routine shedding off old feathers in birds, or of old skin in reptiles, or of old hairs in mammals (see also coat (dog)). In arthropods, such as insects, arachnids and crustaceans, moulting describes the shedding of its exoskeleton (which... The hierarchy of scientific classification In biological classification, family (Latin: familia, plural familiae) is a rank, or a taxon in that rank. ... Suitor redirects here. ...

For most birds, moult begins at a certain specific point, called a focus (plural foci), on the wing or tail and proceeds in a sequential manner in one or both directions from there. For example, most passerines have a focus between the innermost primary (P1, using the numbering scheme explained above) and outermost secondary (S1), and a focus point in the middle of the center pair of rectrices.^[30] As passerine moult begins, the two feathers closest to the focus are the first to drop. When replacement feathers reach roughly half of their eventual length, the next feathers in line (P2 and S2 on the wing, and both R2s on the tail) are dropped. This pattern of drop and replacement continues until moult reaches either end of the wing or tail. The speed of the moult can vary somewhat within a species. Some passerines that breed in the Arctic, for example, drop many more flight feathers at once (sometimes becoming briefly flightless) in order to complete their entire wing moult prior to migrating south, while those same species breeding at lower latitudes undergo a more protracted moult.^[31] The red line indicates the 10°C isotherm in July, sometimes used to define the Arctic region border Artificially coloured topographical map of the Arctic region For the ship, see SS Arctic. ... Flock of Barnacle Geese during autumn migration Bird migration refers to the regular seasonal journeys undertaken by many species of birds. ... This article is about the geographical term. ...

Young White-bellied Sea-Eagle (Haliaeetus leucogaster) in flight, showing moult waves in wings

In many species, there is more than one focus along the wing. Here, moult begins at all foci simultaneously, but generally proceeds only in one direction. Most grouse, for example, have two wing foci: one at the wingtip, the other between feathers P1 and S1. In this case, moult proceeds descendantly from both foci. Many large, long-winged birds have multiple wing foci. Binomial name Haliaeetus leucogaster Gmelin, 1788 The White-bellied Sea Eagle (Haliaeetus leucogaster) is a large bird of prey in the family Accipitridae which also includes many other diurnal raptors such as kites, buzzards and harriers. ...

Birds that are heavily "wing-loaded"—that is, heavy-bodied birds with relatively short wings—have great difficulty flying with the loss of even a few flight feathers. A protracted moult like the one described above would leave them vulnerable to predators for a sizeable portion of the year. Instead, these birds lose all their flight feathers at once. This leaves them completely flightless for a period of three to four weeks, but means their overall period of vulnerability is significantly shorter than it would otherwise be. Eleven families of birds, including loons, grebes and most waterfowl, have this moult strategy. This snapping turtle is trying to make a meal of a Canada goose, but the goose is too wary. ... A year (from Old English gÄ“r) is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... For more details on each day of the week, see days of the week. ... Global distribution of Gaviidae (breeding and winter ranges combined) Species Gavia stellata Gavia arctica Gavia pacifica Gavia immer Gavia adamsii The Loons (N.Am. ... Families Anhimidae Anseranatidae Anatidae †Dromornithidae †Presbyornithidae The order Anseriformes contains about 150 species of birds in three families: the Anhimidae (the screamers), Anseranatidae (the Magpie-goose), and the Anatidae, which includes over 140 species of waterfowl, among them the ducks, geese, and swans. ...

Arboreal woodpeckers, which depend on their tails—particularly the strong central pair of rectrices—for support while they feed, have a unique tail moult. Rather than moulting their central tail feathers first, as most birds do, they retain these feathers until last. Instead the second pair of rectrices (both R2 feathers) are the first to drop. (In some species in the genera Celeus and Dendropicos, the third pair is the first dropped.) The pattern of feather drop and replacement proceeds as described for passerines (above) until all other rectrices have been replaced; only then are the central tail rectrices moulted. This provides some protection to the growing feathers, since they're always covered by at least one existing feather, and also ensures that the bird's newly strengthened tail is best able to cope with the loss of the crucial central rectrices. Ground-feeding woodpeckers, such as the wrynecks, do not have this modified moult strategy; in fact, wrynecks moult their outer tail feathers first, with moult proceeding proximally from there. Genera Melanerpes Sphyrapicus Xiphidiopicus Dendropicos Dendrocopos Picoides Veniliornis Campethera Geocolaptes Dinopium Meiglyptes Hemicircus Micropternus Picus Mulleripicus Dryocopus Celeus Piculus Colaptes Campephilus Chrysocolaptes Reinwardtipicus Blythipicus Gecinulus Sapheopipo For other uses, see Woodpecker (disambiguation). ... Species The wrynecks (genus Jynx) are a small but distinctive group of small Old World woodpeckers. ... In zootomy, several terms are used to describe the location of organs and other structures in the body of bilateral animals. ...

Age differences in flight feathers

There are often substantial differences between the remiges and rectrices of adults and juveniles of the same species. Because all juvenile feathers are grown at once—a tremendous energy burden to the developing bird—they are softer and of poorer quality than the equivalent feathers of adults, which are moulted over a longer period of time (as long as several years in some cases).^[32] As a result, they wear more quickly.

As feathers grow at variable rates, these variations lead to visible dark and light bands in the fully formed feather. These so called growth bars and their widths have been used to determine the daily nutritional status of birds. Each light and dark bar correspond to around 24 hours and the use of this technique has been called ptilochronology (analogous to dendrochronology).^[33][34] The growth rings of an unknown tree species, at Bristol Zoo, England Pinus taeda Cross section showing annual rings, Cheraw, South Carolina Pine stump showing growth rings Dendrochronology or tree-ring dating is the method of scientific dating based on the analysis of tree-ring growth patterns. ...

In general, juveniles have feathers which are narrower and more sharply-pointed at the tip.^[35][36] This can be particularly visible when the bird is in flight, especially in the case of raptors. The trailing edge of the wing of a juvenile bird can appear almost serrated, due to the feathers' sharp tips, while that of an older bird will be straighter-edged.^[35] The flight feathers of a juvenile bird will also be uniform in length, since they all grew at the same time. Those of adults will be of various lengths and levels of wear, since each is moulted at a different time.^[32]

The flight feathers of adults and juveniles can differ considerably in length, particularly among the raptors. Overall, juveniles tend to have slightly longer rectrices, and shorter, broader wings (with shorter outer primaries, and longer inner primaries and secondaries) than do adults of the same species.^[37] However, there are many exceptions. In longer-tailed species, such as Swallow-tailed Kite, Secretary Bird and European Honey Buzzard, for example, juveniles have shorter rectrices than adults do. Juveniles of some Buteo buzzards have narrower wings than adults do, while those of large juvenile falcons are longer. Binomial name Elanus forficatus (Linnaeus, 1758) The Swallow-tailed Kite (Elanus forficatus) is an elanid kite found in southern North America to northern South America. ... Binomial name Sagittarius serpentarius (Miller,JF, 1779) The Secretary Bird, Sagittarius serpentarius, is an extraordinary member of the bird of prey family. ... Binomial name Pernis apivorus (Linnaeus, 1758) The Honey Buzzard (Pernis apivorus) is a bird of prey in the family Accipitridae which also includes many other diurnal raptors such as kites, eagles and harriers. ...

Experts theorize that the differences help young birds compensate for their inexperience, weaker flight muscles and poorer flying ability.^[37]

Wing formula

Measuring primary lengths, one of the steps in determining a bird's wing formula

A wing formula describes the shape of distal end of a bird's wing in a mathematical way. It can be used to help distinguish between species with similar plumages, and thus is particularly useful for those who ring (band) birds.^[9] Mathematics is commonly defined as the study of patterns of structure, change, and space; more informally, one might say it is the study of figures and numbers. Mathematical knowledge is constantly growing, through research and application, but mathematics itself is not usually considered a natural science. ... Bird ringing (also known as bird banding) is an aid to studying wild birds, by attaching a small individually numbered metal or plastic ring to their legs or wings, so that various aspects of the birds life can be studied by the ability to re-find the same individual...

To determine a bird's wing formula, the distance between the tip of the most distal primary and the tip of its greater covert (the longest of the feathers that cover and protect the shaft of that primary) is measured in millimeters. In some cases, this results in a positive number (e.g., the primary extends beyond its greater covert), while in other cases it's a negative number (e.g. the primary is completely covered by the greater covert, as happens in some passerine species). Next, the longest primary feather is identified, and the differences between the length of that primary and that of all remaining primaries and of the longest secondary are also measured, again in millimeters. If any primary shows a notch or emargination, this is noted, and the distance between the feather's tip and any notch is measured, as is the depth of the notch. All distance measurements are made with the bird's wing closed, so as to maintain the relative positions of the feathers.

While there can be considerable variation across members of a species—and while the results are obviously impacted by the effects of molt and feather regeneration—even very closely related species show clear differences in their wing formulas.^[9]

Primary extension

The distance that a bird's longest primaries extend beyond its longest secondaries (or tertials) when its wings are folded is referred to as the primary extension or primary projection.^[38] As with wing formulae, this measurement is useful for distinguishing between similarly plumaged birds; however, unlike wing formulae, it isn't necessary to have the bird in-hand to make the measurement. Rather, this is a useful relative measurement—some species have long primary extensions, while others have shorter ones. Among the Empidonax flycatchers of the Americas, for example, the Dusky Flycatcher has a much shorter primary extension than does the very similarly-plumaged Hammond's Flycatcher.^[38] Europe's Common Skylark has a long primary projection, while that of the near-lookalike Oriental Skylark is very short.^[39] Species See text. ... Genera Many, see text. ... World map showing the Americas CIA political map of the Americas in an equal-area projection The Americas are the lands of the New World, consisting of the continents of North America and South America with their associated islands and regions. ... Binomial name Empidonax oberholseri Phillips, 1939 The Dusky Flycatcher, Empidonax oberholseri, is a small insect-eating bird of the tyrant flycatcher family. ... For other uses see Skylark (disambiguation). ... Binomial name Alauda gulgula Franklin, 1831 The Oriental Skylark (Alauda gulgula), also known as Oriental Lark or Small Skylark, is a species of skylark found in South Asia and South-East Asia. ...

See also

• Bird anatomy
• Bird flight
• Drumming (snipe)
• Pinioning
• Plumage

External anatomy (topography) of a typical bird: 1 Beak, 2 Head, 3 Iris, 4 Pupil, 5 Mantle, 6 Lesser coverts, 7 Scapulars, 8 Coverts, 9 Tertials, 10 Rump, 11 Primaries, 12 Vent, 13 Thigh, 14 Tibio-tarsal articulation, 15 Tarsus, 16 Feet, 17 Tibia, 18 Belly, 19 Flanks, 20 Breast... Flight is the main mode of locomotion used by most of the worlds bird species. ... Diagram of pinioning, from Wild Waterfowl and its Captive Management Vol. ... Closeup on a single white feather A feather is one of the epidermal growths that forms the distinctive outer covering, or plumage, on a bird. ...

Notes

References

• Campbell, Bruce & Lack, Elizabeth, eds. (1985), A Dictionary of Birds, Carlton, England: T and A D Poyser, ISBN 0-85661-039-9
• del Hoyo, Josep; Elliott, Andrew & Sargatal, Jordi, eds. (1992), Handbook of the Birds of the World, Volume 1: Ostrich to Ducks, Barcelona: Lynx Edicions, ISBN 84-87334-10-5
• Grubb, T. C. (1989), "Ptilochronology: feather growth bars as indicators of nutritional status.", Auk 106: 314–320
• del Hoyo, Josep; Elliott, Andrew & Sargatal, Jordi, eds. (1997), Handbook of the Birds of the World, Volume 4: Sandgrouse to Cuckoos, Barcelona: Lynx Edicions, ISBN 84-87334-22-9
• del Hoyo, Josep; Elliott, Andrew & Christie, David, eds. (2004), Handbook of the Birds of the World, Volume 9: Cotingas to Pipits and Wagtails, Barcelona: Lynx Edicions, ISBN 84-87334-69-5
• Ehrlich, Paul R.; Dobkin, Darryl A. & Wheye, Darryl et al. (1994), The Birdwatcher's Handbook, Oxford University Press, ISBN 0-19-858407-5
• Ferguson-Lees, James & Christie, David A. (2001), Raptors of the World, London: Christopher Helm, ISBN 0-7136-8026-1
• Forsman, Dick (1999), The Raptors of Europe and the Middle East, London: T and A D Poyser, ISBN 0-85661-098-4
• Jenni, Lukas & Winkler, Raffael (1994), Moult and Ageing of European Passerines, London: Academic Press, ISBN 0-12-384150-X
• Paulson, Dennis (2005), Shorebirds of North America, London: Christopher Helm, ISBN 0-7136-7377-X
• Shawkey, Matthew D.; Beck, Michelle L. & Hill, Geoffrey E. (2003), "Use of a gel documentation system to measure feather growth bars.", J. Field Ornithol. 74 (2): 125–128
• Sibley, David (2001), The Sibley Guide to Bird Life & Behaviour, London: Christopher Helm, ISBN 0-7136-6250-6
• Trail, Pepper (2001), Wing Feathers, U.S. Fish and Wildlife Service, <http://www.lab.fws.gov/lab/docs/idnotes/pdf/WingFeathers-prnt.pdf>. Retrieved on 22 May 2007

The Handbook of the Birds of the World is a multi-volume series produced by Spanish publishing house Lynx Edicions. ... Paul Ralph Ehrlich (born May 29, 1932 in Philadelphia, Pennsylvania) is a Stanford University professor and a renowned entomologist specializing in Lepidoptera (butterflies). ... David Allen Sibley (born 1962, New York) is an American ornithologist. ...

External links

• Wing Feathers—US Fish and Wildlife Service document Contains excellent photographic examples of emargination and notching in raptor remiges.
• Video of feeding Magellanic Woodpecker (Campephilus magellanicus) Shows use of rectrices for bracing.
• Video of singing male Superb Lyrebird (Menuta novaehollandiae) Shows long modified rectrices which are used in display (though the video doesn't show full display).
• Video of male Club-winged Manakin (Machaeropterus deliciosus) Shows use of secondary remiges to produce sound.
• Cornell Laboratory of Ornithology's American Woodcock (Scolopax minor) recordings #94216 has a good example of the sounds made by remiges during courtship display flight, starting at about 2:32.
• Sound made by rectrices in courtship flight of Common Snipe (Gallinago gallinago)