50-468: Gavia may refer to: Gavia (bird) , a genus of birds to which the loons belong Gavia Pass , in the Italian Alps Monte Gavia , a mountain of Lombardy, Italy La Gavia, Guanajuato , Mexico, a populated place USS Gavia (AM-363) , a World War II U.S. Navy minesweeper Gavia gens , an ancient Roman family La Gavia (Madrid Metro) ,
100-623: A flock because it is conspicuous. A complete albino often has weak eyesight and brittle wing and tail feathers, which may reduce its ability to fly. In flocks, albinos are often harassed by their own species. Such observations have been made among red-winged blackbirds , barn swallows , and African penguins . In a nesting colony of the latter, three unusual juveniles—one black-headed, one white-headed, and one full albino—were shunned and abused by companions. Albinism has been reported in all orders and in 54 families of North American birds. The American robin and house sparrow led bird species in
150-581: A bird is not haphazard but rather emerges in organized, overlapping rows and groups, and these feather tracts are known by standardized names. Most birds moult twice a year, resulting in a breeding or nuptial plumage and a basic plumage . Many ducks and some other species such as the red junglefowl have males wearing a bright nuptial plumage while breeding and a drab eclipse plumage for some months afterward. The painted bunting 's juveniles have two inserted moults in their first autumn, each yielding plumage like an adult female. The first starts
200-433: A few days after fledging replacing the juvenile plumage with an auxiliary formative plumage ; the second a month or so later giving the formative plumage . Abnormal plumages include a variety of conditions. Albinism , total loss of colour, is rare, but partial loss of colours is more common. Some species are colour polymorphic , having two or more colour variants. A few species have special types of polymorphism, as in
250-400: A group of aquatic birds found in much of North America and northern Eurasia . All living species of loons are members of the genus Gavia , family Gaviidae and order Gaviiformes . Loons, which are the size of large ducks or small geese , resemble these birds in shape when swimming. Like ducks and geese, but unlike coots (which are Rallidae ) and grebes ( Podicipedidae ),
300-486: A metro station Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Gavia . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Gavia&oldid=1025451091 " Categories : Disambiguation pages Place name disambiguation pages Hidden categories: Short description
350-406: A necropsy of a bald eagle found floating on a Maine lake (beside the floating body of a loon chick) found that the eagle had been stabbed through the heart by an adult loon's beak. Biologists , especially from Chapman University , have extensively studied the mating behaviour of the common loon ( G. immer ). Contrary to popular belief, pairs seldom mate for life . Indeed, a typical adult loon
400-433: A spear-shaped bill. Males are larger on average, but relative size is only apparent when the male and female are together. In winter, plumage is dark grey above, with some indistinct lighter mottling on the wings, and a white chin, throat and underside. The specific species can then be distinguished by certain features, such as the size and colour of the head, neck, back and bill. But reliable identification of loons in winter
450-499: Is albino (from the Latin albus , "white") has white feathers in place of coloured ones on some portion of its body. A bird that is naturally white, such as a swan , goose , or egret , is not an albino, nor is a bird that has seasonally alternating white plumage. Four degrees of albinism have been described. The most common form is termed partial albinism , in which local areas of the bird's body, such as certain feathers, are lacking
500-401: Is a genetically conditioned character in domestic fowl ( Gallus gallus domesticus ). Males with this condition develop a female-type plumage, although otherwise look and respond like virile males. In some breeds, one can see males that have a plumage completely similar in all aspects to that of females. The trait is controlled by a simple autosomic dominant gene , whose expression is limited to
550-608: Is also found in tubenoses ( Procellariiformes ) and penguins (Sphenisciformes), both relatives of the loons. Loons are excellent swimmers, using their feet to propel themselves above and under water. However, since their feet are located far back on the body, loons have difficulty walking on land, though they can effectively run short distances to reach water when frightened. Thus, loons avoid coming to land, except for mating and nesting. Loons fly strongly, though they have high wing loading (mass to wing area ratio), which complicates takeoff. Indeed, most species must run upwind across
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#1732855149827600-572: Is called eclipse plumage . When they shed feathers to go into an eclipse, the ducks become flightless for a short period. Some duck species remain in eclipse for one to three months in the late summer and early fall, while others retain the cryptic plumage until the next spring when they undergo another moult to return to their breeding plumage. Although mainly found in the Anatidae , a few other species, including related red junglefowl , most fairywrens and some sunbirds also have an eclipse plumage. In
650-524: Is different from Wikidata All article disambiguation pages All disambiguation pages Gavia (bird) Family-level: Colymbidae Vigors , 1825 (but see text ) Colymbinae Bonaparte , 1831 (but see text ) Urinatores Vieillot , 1818 Urinatoridae Vieillot, 1818 Urinatorides Vieillot, 1818 Genus-level: Colymbus Linnaeus , 1758 (but see text ) Urinator Lacépède , 1799 Loons ( North American English ) or divers ( British / Irish English ) are
700-423: Is imbalanced it produces colour shifts that are termed schizochroisms (including xanthochromism – an overabundance of yellow – and axanthism – lack of yellow – which are commonly bred in cagebirds such as budgerigars ). A reduction in eumelanin leads to non-eumelanin schizochroism with an overall fawn plumage while a lack of phaeomelanin results in grey-coloured non-phaeomelanin schizochroism. Carotenism refers to
750-481: Is likely to have several mates during its lifetime because of territorial takeover. Each breeding pair must frequently defend its territory against "floaters" (territory-less adults) trying to evict at least one owner and seize the breeding site. Territories that have produced chicks in the past year are especially prone to takeovers, because nonbreeding loons use chicks as cues to indicate high-quality territories. One-third of all territorial evictions among males result in
800-452: Is often brighter than the basic plumage, for sexual display, but may also be cryptic to hide incubating birds that might be vulnerable on the nest. The Humphrey–Parkes terminology requires some attention to detail to name moults and plumages correctly. Many male ducks have bright, colourful plumage, exhibiting strong sexual dimorphism . However, they moult into a dull plumage after breeding in mid-summer. This drab, female-like appearance
850-423: Is often difficult even for experts – particularly as the smaller immature birds look similar to winter-plumage adults, making size an unreliable means of identification. Gaviiformes are among the few groups of birds in which the young moult into a second coat of down feathers after shedding the first one, rather than growing juvenile feathers with downy tips that wear off, as is typical in many birds. This trait
900-441: Is rare, occurring to any extent in perhaps one in 1800 individuals. It involves loss of colour in all parts including the iris of the eyes, bills, skin, legs, and feet. It is usually the result of a genetic mutation causing the absence of tyrosinase , an enzyme essential for melanin synthesis. Leucism (which includes what used to be termed as "partial albinism") refers to loss of pigments in some or all parts of feathers. A bird that
950-555: Is refracted. Dilution regularly occurs in normal plumage (grey, buff, pink and cream colours are usually produced by this process), but may in addition occur as an aberration (e.g., all normally black plumage becoming grey). In some birds – many true owls (Strigidae), some nightjars (Caprimulgidae) and a few cuckoos ( Cuculus and relatives) being widely known examples – there is colour polymorphism . This means that two or more colour variants are numerous within their populations during all or at least most seasons and plumages; in
1000-642: The Guianan cock-of-the-rock or birds of paradise – retain their exuberant plumage and sexual dimorphism at all times, moulting as ordinary birds do once annually. There are hereditary as well as non-hereditary variations in plumage that are rare and termed abnormal or aberrant plumages. Melanism refers to an excess of black or dark colours. Erythromelanism or erythrism is the result of excessive reddish-brown erythromelanin deposition in feathers that normally lack melanin. Melanin of different forms combine with xanthophylls to produce colour mixtures and when this combination
1050-560: The Late Miocene . Study of the interrelationships of the extant species has found that the red-throated loons are the most basal of the five species. Gavia stellata G. arctica G. pacifica G. immer G. adamsii † Gavia egeriana † G. schultzi † G. howardae G. stellata † G. brodkorbi † G. paradoxa † G. moldavica † G. concinna G. arctica G. pacifica † G. fortis G. adamsii G. immer Nearly ten prehistoric species have been named to date in
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#17328551498271100-522: The Late Pliocene of Orciano Pisano , Italy , is known from a cervical vertebra that may or may not have been from a loon. If so, it was from a bird slightly smaller than the common loon . Older authors were quite sure the bone was indeed from a Gavia and even considered G. concinna a possibly junior synonym of it. This is now regarded as rather unlikely due to the quite distinct range and age. The Early Pliocene Gavia skull from Empoli (Italy)
1150-399: The incidence of albinism. Albinistic white appears to replace brown pigments more often than red or yellow ones; records suggest a greater incidence in crows , ravens , and hawks than in goldfinches or orioles . Several kinds of albinism in chickens has been described: A complete albinism controlled by an autosomal recessive gene and two different kinds of partial albinism. One of
1200-495: The smew ( Mergellus albellus ). This small sea-duck is quite unrelated to loons and just happens to be another black-and-white seabird which swims and dives for fish. It is not likely that the ancient Romans had much knowledge of loons, as these are limited to more northern latitudes and since the end of the last glacial period seem to have occurred only as rare winter migrants in the Mediterranean region. The term gavia
1250-440: The superb and splendid fairywrens , very old males (over about four years) may moult from one nuptial plumage to another whereas in the red-backed and white-winged fairywrens , males do not acquire nuptial plumage until four years of age – well after they become sexually mature and indeed longer than the vast majority of individuals live. In contrast to the ducks, males of hummingbirds and most lek-mating passerines – like
1300-1110: The South Baltic and directly over land to the Black Sea or Mediterranean. Loons can live as long as 30 years and can hold their breath for as long as 90 seconds while underwater. Loons are migratory birds, and in the winter months they move from their northern freshwater lake nesting habitats to southern marine coastlines. They are well-adapted to this change in salinity, however, because they have special salt glands located directly above their eyes. These glands filter out salts in their blood and flush this salty solution out through their nasal passages, which allows them to immediately consume fish from oceans and drink saltwater after their long migration. Loons find their prey by sight. They eat mainly fish , supplemented with amphibians , crustaceans and similar mid-sized aquatic fauna . Specifically, they have been noted to feed on crayfish , frogs , snails , salamanders and leeches . They prefer clear lakes because they can more easily see their prey through
1350-400: The abnormal distribution of carotenoid pigments. The term "dilution" is used for situations where the colour is of a lower intensity overall; it is caused by decreased deposition of pigment in the developing feather, and can thus not occur in structural coloration (i.e., "dilute blue" does not exist); pale structural colors are instead achieved by shifting the peak wavelength at which light
1400-531: The above-mentioned examples a brown (phaeomelanin) and grey (eumelanin) morph exist, termed "hepatic form" particularly in the cuckoos. Other cases of natural polymorphism are of various kinds; many are melanic/nonmelanic (some paradise-flycatchers , Terpsiphone , for example), but more unusual types of polymorphism exist – the face colour of the Gouldian finch ( Erythrura gouldiae ) or the courtship types of male ruffs ( Philomachus pugnax ). Albinism in birds
1450-400: The absence of pigment in the irises . The beak , legs, and feet are very pale or white. Albino adults are rare in the wild because their eyesight is poor resulting in greater risk of predation. They are likely easier targets for predators because their colour distinguishes them from their environment. Falconers have observed that their trained birds are likely to attack a white pigeon in
1500-573: The bones of frogs and salamanders. The gastroliths may also be involved in stomach cleaning as an aid to regurgitation of indigestible food parts. Loons may inadvertently ingest small lead pellets, released by anglers and hunters, that will contribute to lead poisoning and the loon's eventual death. Jurisdictions that have banned the use of lead shot and sinkers include but are not limited to Maine , New Hampshire , Vermont , Michigan , some areas of Massachusetts , Yellowstone National Park , Canada , Great Britain , and Denmark . Loons nest during
1550-418: The breeding season, known as the pre-basic moult . This resulting covering of feathers, which will last either until the next breeding season or until the next annual moult, is known as the basic plumage. Many species undertake another moult before the breeding season known as the pre-alternate moult , the resulting breeding plumage being known as the alternate plumage or nuptial plumage. The alternate plumage
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1600-569: The death of the owner; in contrast, female loons usually survive. Birds that are displaced from a territory but survive usually try to re-mate and (re)claim a breeding territory later in life. In 2020, a loon hatched for the first time in over a century in Southeastern Massachusetts at Fall River, the Massachusetts Division of Fisheries and Wildlife and Biodiversity Research Institute. The chicks were relocated in 2015 with
1650-1206: The eggs are lost, the pair may re-nest, usually in a different location. Since the nest is very close to the water, rising water may induce the birds to slowly move the nest upwards, over a metre. Despite the roughly equal participation of the sexes in nest building and incubation, analysis has shown clearly that males alone select the location of the nest. This pattern has the important consequence that male loons, but not females, establish significant site-familiarity with their territories that allows them to produce more chicks there over time. Sex-biased site-familiarity might explain, in part, why resident males fight so hard to defend their territories. Most clutches consist of two eggs, which are laid in May or June, depending upon latitude. Loon chicks are precocial , able to swim and dive right away, but will often ride on their parents' back during their first two weeks to rest, conserve heat, and avoid predators. Chicks are fed mainly by their parents for about six weeks but gradually begin to feed themselves over time. By 11 or 12 weeks, chicks gather almost all of their own food and have begun to fly. In 2019,
1700-404: The future nest site, and build their nests close to the water, preferring sites that are completely surrounded by water such as islands or emergent vegetation. Loons use a variety of materials to build their nests including aquatic vegetation, pine needles, leaves, grass, moss and mud. Sometimes, nest material is almost lacking. Both male and female build the nest and incubate jointly for 28 days. If
1750-524: The genus Gavia , and about as many undescribed ones await further study. The genus is known from the Early Miocene onwards, and the oldest members are rather small (some are smaller than the red-throated loon ). Throughout the late Neogene , the genus by and large follows Cope's Rule (that population lineages tend to increase in body size over evolutionary time). List of fossil Gavia species List of fossil Gavia specimens "Gavia" portisi from
1800-712: The genus Gavia . It has been suggested that the genus Gavia originated in Europe during the Paleogene . The earliest species, G. egeriana , was found in early Miocene deposits in Dolnice in the Czech Republic. During the remainder of the Miocene , Gavia managed to disperse into North America via the Atlantic coastlines, eventually making their way to the continent's Pacific coastlines by
1850-414: The genus name to refer to grebes, while Europeans used it for loons, following Nicholas Aylward Vigors and Richard Bowdler Sharpe . The International Commission on Zoological Nomenclature tried to settle this issue in 1956 by declaring Colymbus a suppressed name unfit for further use and establishing Gavia , created by Johann Reinhold Forster in 1788, as the valid genus name for the loons. However,
1900-494: The head droops more than in similar aquatic birds. Male and female loons have identical plumage , which is largely patterned black-and-white in summer, with grey on the head and neck in some species. All have a white belly. This resembles many sea-ducks (Merginae) – notably the smaller goldeneyes ( Bucephala ) – but is distinct from most cormorants, which rarely have white feathers, and if so, usually as large rounded patches rather than delicate patterns. All species of loons have
1950-522: The hopes of re-establishing breeding and nesting patterns. The European Anglophone name "diver" comes from the bird's habit of catching fish by swimming calmly along the surface and then abruptly plunging into the water. The North American name "loon" likely comes from either the Old English word lumme , meaning lummox or awkward person, or the Scandinavian word lum meaning lame or clumsy. Either way,
2000-554: The loon's toes are connected by webbing . The loons may be confused with the cormorants (Phalacrocoracidae), but can be distinguished from them by their distinct call. Cormorants are not-too-distant relatives of loons, and like them are heavy-set birds whose bellies, unlike those of ducks and geese, are submerged when swimming. Loons in flight resemble plump geese with seagulls ' wings that are relatively small in proportion to their bulky bodies. The bird points its head slightly upwards while swimming, but less so than cormorants. In flight,
2050-401: The male ruff which has an assortment of different colours around the head and neck in the breeding season only. Hen feathering is an inherited plumage character in domestic fowl controlled by a single gene. Plumology (or plumage science ) is the name for the science that is associated with the study of feathers. Almost all species of birds moult at least annually, usually after
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2100-450: The name refers to the loon's poor ability to walk on land. Another possible derivation is from the Norwegian word lom for these birds, which comes from Old Norse lómr , possibly cognate with English "lament", referring to the characteristic plaintive sound of the loon. The scientific name Gavia refers to seabirds in general. The scientific name Gavia was the Latin term for
2150-446: The partial albinisms is sex-linked and the other is autosomal recessive. A fourth kind of albinism severely reduce pigmentation in the eyes, but only dilutes the pigment in the plumage. Abnormally white feathers are not always due to albinism. Injury or disease may change their color, including dietary deficiencies or circulatory problems during feather development. Aging may also turn a bird's feathers white. Hen feathering in cocks
2200-474: The pigment melanin . The white areas may be symmetrical, with both sides of the bird showing a similar pattern. In imperfect albinism , the pigment is partially inhibited in the skin , eyes , or feathers, but is not absent from any of them. Incomplete albinism is the complete absence of pigment from the skin, eyes, or feathers, but not all three. A completely albino bird is the most rare. The eyes in this case are pink or red, because blood shows through in
2250-447: The situation was not completely resolved even then, and the following year the ICZN had to act again to prevent Louis Pierre Vieillot 's 1818 almost-forgotten family name Urinatoridae from overruling the much younger Gaviidae. Some eminent ornithologists such as Pierce Brodkorb tried to keep the debate alive, but the ICZN's solution has been satisfactory. All living species are placed in
2300-437: The summer on freshwater lakes and/or large ponds. Smaller bodies of water (up to 0.5 km ) will usually only have one pair. Larger lakes may have more than one pair, with each pair occupying a bay or section of the lake. The red-throated loon, however, may nest colonially, several pairs close together, in small Arctic tarns and feed at sea or in larger lakes, ferrying the food in for the young. Loons mate on land, often on
2350-489: The water's surface with wings flapping to generate sufficient lift to take flight. Only the red-throated loon ( G. stellata ) can take off from land. Once airborne, loons are capable of long flights during migration. Scientists from the U.S. Geological Survey, who have implanted satellite transmitters in some individuals, have recorded daily flights of up to 1078 km in a 24-hour period, which probably resulted from single movements. North European loons migrate primarily via
2400-419: The water. The loon uses its pointy bill to stab or grasp prey. They eat vertebrate prey headfirst to facilitate swallowing, and swallow all their prey whole. To help digestion, loons swallow small pebbles from the bottoms of lakes. Similar to grit eaten by chickens , these gastroliths may assist the loon's gizzard in crushing the hard parts of the loon's food such as the exoskeletons of crustaceans and
2450-586: Was referred to G. concinna , and thus could conceivably have been of "G." portisi if that was indeed a loon. The holotype vertebra may now be lost, which would make "G." portisi a nomen dubium . Plumage Plumage (from Latin pluma 'feather') is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can be different colour morphs . The placement of feathers on
2500-519: Was transferred from the ducks to the loons only in the 18th century. Earlier naturalists referred to the loons as mergus (the Latin term for diving seabirds of all sorts) or colymbus , which became the genus name used in the first modern scientific description of a Gavia species (by Carl Linnaeus ) in 1758. Unfortunately, confusion about whether Linnaeus' " wastebin genus " Colymbus referred to loons or grebes abounded. North American ornithologists used
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