44-410: † C. minutus Milne-Edwards, 1867 † C. anglicus Lydekker, 1891 † C. metzleri Mayr, 2004 Gavioides The genus Colymboides contains three species of early loon dating from the late Oligocene or early Miocene . They are considered to be the earliest known unambiguous gaviiform fossils . The genus is widely known from early Priabonian – about 37 million years ago in
88-403: A sock from one's foot by grabbing the open end and pulling it over itself. The snake's skin is often left in one piece after the moulting process, including the discarded brille (ocular scale), so that the moult is vital for maintaining the animal's quality of vision. The skins of lizards , in contrast, generally fall off in pieces. Both frogs and salamanders moult regularly and consume
132-426: A bird's body weight, it takes a large amount of energy to replace them. For this reason, moults often occur immediately after the breeding season, but while food is still abundant. The plumage produced during this time is called postnuptial plumage. Prenuptial moulting occurs in red-collared widowbirds where the males replace their nonbreeding plumage with breeding plumage. It is thought that large birds can advance
176-448: A body weight loss of 25 to 35%, which stimulates the hen to lose her feathers, but also reinvigorates egg-production. Some flocks may be force-moulted several times. In 2003, more than 75% of all flocks were force-moulted in the US. Other methods of inducing a moult include low-density diets (e.g. grape pomace, cotton seed meal, alfalfa meal) or dietary manipulation to create an imbalance of
220-400: 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 ),
264-406: 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
308-404: A particular nutrient(s). The most important among these include manipulation of minerals including sodium (Na), calcium (Ca), iodine (I) and zinc (Zn), with full or partially reduced dietary intakes. Squamates periodically engage in moulting, as their skin is scaly . The most familiar example of moulting in such reptiles is when snakes "shed their skin". This is usually achieved by
352-459: A protected habitat with a reliable food supply during that time. While the plumage may appear thin or uneven during the moult, the bird's general shape is maintained despite the loss of apparently many feathers; bald spots are typically signs of unrelated illnesses, such as gross injuries, parasites, feather pecking (especially in commercial poultry), or (in pet birds) feather plucking . Some birds will drop feathers, especially tail feathers, in what
396-459: A slow process: birds rarely shed all their feathers at any one time. The bird must retain sufficient feathers to regulate its body temperature and repel moisture. The number and area of feathers that are shed varies. In some moulting periods, a bird may renew only the feathers on the head and body, shedding the wing and tail feathers during a later moulting period. Some species of bird become flightless during an annual "wing moult" and must seek
440-433: 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
484-608: 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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#1733085140958528-422: Is called a "fright moult". The process of moulting in birds is as follows: First, the bird begins to shed some old feathers, then pin feathers grow in to replace the old feathers. As the pin feathers become full feathers, other feathers are shed. This is a cyclical process that occurs in many phases. It is usually symmetrical , with feather loss equal on each side of the body. Because feathers make up 4–12% of
572-787: Is generally quite distinct from modern loons, and may actually belong in a now-extinct family of primitive gaviiforms. The best studied species, Colymboides minutus , was described by Robert Storer as being much smaller than modern loons and not as well adapted to diving. This prehistoric bird article is a stub . You can help Misplaced Pages by expanding it . Loon 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
616-481: 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
660-423: 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
704-709: The Late Eocene – to Early Miocene (late Burdigalian , less than 20 million years ago ) limnic and marine rocks of western Eurasia north of the Alpide belt , between the Atlantic and the former Turgai Sea . It is usually placed in the Gaviidae already, but usually in a subfamily Colymboidinae , with the modern-type loons making up the Gaviinae. But the Colymboides material
748-560: 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
792-522: 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)
836-656: The common bulbul , breeding seasonality is weak at the population level, instead moult can show high seasonality with individuals probably under strong selection to match moult with peak environmental conditions. A 2023 paleontological analysis concluded that moulting probably evolved late in the evolutionary lineage of birds. In some countries, flocks of commercial layer hens are force-moulted to reinvigorate egg-laying. This usually involves complete withdrawal of their food and sometimes water for 7–14 days or up to 28 days under experimental conditions, which presumably reflect standard farming practice in some countries. This causes
880-495: 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
924-1110: 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
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#1733085140958968-573: 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
1012-569: 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
1056-1206: 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,
1100-408: The entire exoskeleton in arthropods , including the wings in some insects . In birds , moulting is the periodic replacement of feathers by shedding old feathers while producing new ones. Feathers are dead structures at maturity which are gradually abraded and need to be replaced. Adult birds moult at least once a year, although many moult twice and a few three times each year. It is generally
1144-404: 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
1188-524: 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
1232-662: 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
1276-414: 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,
1320-494: 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
1364-522: 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,
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1408-554: 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,
1452-424: The morphology of successive instars . A new skin can replace structures, such as by providing new external lenses for eyes. The new exoskeleton is initially soft but hardens after the moulting of the old exoskeleton. The old exoskeleton is called an exuviae . While moulting, insects cannot breathe. In the crustacean Ovalipes catharus molting must occur before they mate. Most dogs moult twice each year, in
1496-446: The moult of severely damaged feathers. Determining the process birds go through during moult can be useful in understanding breeding, migration and foraging strategies. One non-invasive method of studying moult in birds is through using field photography. The evolutionary and ecological forces driving moult can also be investigated using intrinsic markers such as stable hydrogen isotope ( δ2H ) analysis. In some tropical birds, such as
1540-497: 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
1584-447: 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
1628-435: The skin, with some species moulting in pieces and others in one piece. In arthropods , such as insects , arachnids and crustaceans , moulting is the shedding of the exoskeleton , which is often called its shell , typically to let the organism grow. This process is called ecdysis . Most Arthropoda with soft, flexible skins also undergo ecdysis. Ecdysis permits metamorphosis , the sometimes radical difference between
1672-413: The snake rubbing its head against a hard object, such as a rock (or between two rocks) or piece of wood, causing the already stretched skin to split. At this point, the snake continues to rub its skin on objects, causing the end nearest the head to peel back on itself, until the snake is able to crawl out of its skin, effectively turning the moulted skin inside-out. This is similar to how one might remove
1716-437: 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
1760-489: 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
1804-419: 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
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1848-593: The year, or at specific points in its life cycle. In medieval times, it was also known as "mewing" (from the French verb "muer", to moult), a term that lives on in the name of Britain's Royal Mews where the King's hawks used to be kept during moulting time before becoming horse stables after Tudor times. Moulting can involve shedding the epidermis (skin), pelage ( hair , feathers , fur , wool ), or other external layer. In some groups, other body parts may be shed, for example,
1892-507: 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 . Moult In biology , moulting ( British English ), or molting ( American English ), also known as sloughing , shedding , or in many invertebrates , ecdysis , is a process by which an animal casts off parts of its body to serve some beneficial purpose, either at specific times of
1936-519: 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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