Loons, which are the size of largeducks or smallgeese, resemble these birds in shape when swimming. Like ducks and geese, but unlikecoots (which areRallidae) andgrebes (Podicipedidae), the loon's toes are connected bywebbing. The loons may be confused with thecormorants (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 withseagulls' 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, the head droops more than in similar aquatic birds.
Male and female loons have identicalplumage, 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 manysea-ducks (Merginae) – notably the smallergoldeneyes (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 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. Reliable identification of loons in winter 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.[2]
The Gaviiformes are among the few groups of birds in which the youngmoult into a second coat ofdown 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 is also found in tubenoses (Procellariiformes) andpenguins (Sphenisciformes), both relatives of the loons.[3]
Loons swimming in Wood Lake, BC, on a summer morning
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.[4]
Loons fly strongly, though they have highwing loading (mass to wing-area ratio), which complicates takeoff. Indeed, most species must run upwind across the water's surface with wings flapping to generate sufficient lift to take flight.[5] Only thered-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.[6] North European loons migrate primarily via 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 under water.[7][8]
Loons are migratory birds, and in the winter, 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.[9]
Common loons sometimes form social gatherings of several adults in late summer. Studies in North America suggest that these events are attended largely by nonbreeding individuals and relate to territory assessment and social familiarity rather than foraging or migration.[10]
Loons find their prey by sight. They eat mainlyfish, supplemented withamphibians,crustaceans, and similar midsized aquaticfauna. Specifically, they have been noted to feed oncrayfish,frogs,snails,salamanders, andleeches. They prefer clear lakes because they can more easily see their prey through the water. Loons use their pointy bills to stab or grasp prey. They eatvertebrate prey headfirst to facilitate swallowing, and swallow all their prey whole.
To help digestion, loons swallow small pebbles from the bottoms of lakes. Similar togrit eaten bychickens, thesegastroliths may assist the loon'sgizzard in crushing the hard parts of the loon's food, such as theexoskeletons of crustaceans and 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 nest during the summer on freshwater lakes and/or large ponds. Smaller bodies of water (up to 0.5 km2) 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 Arctictarns and feed at sea or in larger lakes, ferrying the food in for the young.[7][8]
Loons mate on land, often on 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 males and females build the nest and incubate jointly for 28 days. If the eggs are lost, the pair may renest, 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.[7][8]
Common loon on the nest
Juvenile red-throated loon
Common loon feeding its young
Juvenile common loon with crayfish
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.[11]
Mostclutches consist of two eggs, which are laid in May or June, depending upon latitude. Loon chicks areprecocial, 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.[7][8] In 2019, a necropsy of abald 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.[12]
Biologists, especially fromChapman University, have extensively studied the mating behaviour of thecommon loon (G. immer). Contrary to popular belief, pairs seldommate for life. Indeed, a typical adult loon 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 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.[13][14][15][16]
In 2020, a loon hatched for the first time in over a century in Southeastern Massachusetts at Fall River. The chicks were relocated in 2015 with the hopes of re-establishing breeding and nesting patterns.[17]
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 wordlumme, meaninglummox or awkward person, or the Scandinavian wordlum meaning lame or clumsy. Either way, the name refers to the loon's poor ability to walk on land.[18]
Another possible derivation is from theNorwegian,Swedish andDanish wordlom for these birds, which comes fromOld Norse lómr, possibly cognate with English "lament", referring to the characteristic plaintive sound of the loon.[19]
The scientific nameGavia refers to seabirds in general.[20] Thescientific nameGavia was theLatin term for thesmew (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 theancient Romans had much knowledge of loons, as these are limited to more northernlatitudes and since the end of thelast glacial period seem to have occurred only as rare winter migrants in theMediterranean region.[21][22]
The termgavia was transferred from the ducks to the loons only in the 18th century. Earliernaturalists referred to the loons asmergus (the Latin term for diving seabirds of all sorts) orcolymbus, which became the genus name used in the first modern scientific description of aGavia species (byCarl Linnaeus) in 1758. Unfortunately, confusion about whether Linnaeus' "wastebin genus"Colymbus referred to loons or grebes abounded. North Americanornithologists used the genus name to refer to grebes, while Europeans used it for loons, followingNicholas Aylward Vigors andRichard Bowdler Sharpe.
TheInternational Commission on Zoological Nomenclature tried to settle this issue in 1956 by declaringColymbus a suppressed name unfit for further use and establishingGavia, created byJohann Reinhold Forster in 1788, as the valid genus name for the loons. However, the situation was not completely resolved even then, and the following year the ICZN had to act again to preventLouis Pierre Vieillot's 1818 almost-forgotten family name Urinatoridae from overruling the much younger Gaviidae. Some eminent ornithologists such asPierce Brodkorb tried to keep the debate alive, but the ICZN's solution has been satisfactory.[22][23][24][25]
All living species are placed in the genusGavia. It has been suggested that the genusGavia originated in Europe during thePaleogene. The earliest species,G. egeriana, was found inearly Miocene deposits inDolnice in the Czech Republic. During the remainder of theMiocene,Gavia managed to disperse into North America via theAtlantic coastlines, eventually making their way to the continent'sPacific coastlines by theLate Miocene.[26] Study of the interrelationships of the extant species has found that the red-throated loons are the most basal of the five species.[27]
Cladogram of theGavia species with the inclusion of fossil species.[31]
Nearly ten prehistoric species have been named to date in the genusGavia, 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 thered-throated loon). Throughout the lateNeogene, the genus by and large followsCope's Rule (that population lineages tend to increase in body size over evolutionary time).
†G. brodkorbiHoward, 1978 (Late Miocene of Orange County, United States)
†G. concinnaWetmore, 1940 (Late Miocene/Early Pliocene of west and east United States)
†G. egerianaŠvec, 1982 (Early Miocene of Czechoslovakia ?and Cheswold, Delaware, United States –? Yorktown Early Pliocene of Lee Creek Mine, North Carolina, United States)[32]
†G. fortisOlson &Rasmussen, 2001 (Yorktown Early Pliocene of Lee Creek Mine, North Carolina, United States)[31]
Gavia sp. (Early Pliocene of Kerč Peninsula, Ukraine)[34]
Gavia cf.concinna (San Diego Middle/Late[39] Pliocene of San Diego, California, United States) – two species?[40]
Gavia sp. (Early Pleistocene of Kairy, Ukraine)[34]
Gavia cf.immer (Pleistocene of California and Florida, United States) – possibly aG. immerpaleosubspecies[41]
"Gavia" portisi from theLate Pliocene ofOrciano Pisano,Italy, is known from acervical vertebra that may or may not have been from a loon. If so, it was from a bird slightly smaller than thecommon loon. Older authors were quite sure the bone was indeed from aGavia and even consideredG. concinna a possiblyjunior synonym of it. This is now regarded as rather unlikely due to the quite distinct range and age. TheEarly PlioceneGavia skull fromEmpoli (Italy) was referred toG. concinna, and thus could conceivably have been of"G." portisi if that was indeed a loon. Theholotype vertebra may now be lost, which would make"G." portisi anomen dubium.[41][42]
Various Indigenous myths from theCalifornia region have a recurring figure, Loon or Loon Woman, based on thecommon loon.[43]
TheTlingit ofAlaska believe that loon cries forecast rain.Gaǥeit is named after the common loon (kagit).[44]
Thecommon loon is the provincial bird ofOntario and is depicted on the Canadian one-dollar coin, which has come to be known affectionately as the "loonie".[45]
The common loon is the official state bird ofMinnesota.[46]
Thanks to its inclusion as a preset in theE-mu Emulator, a specific sample of a Canadian loon, notably heard in "Sueño Latino" (1989) and in808 State's "Pacific State" (1989), has become a recurring motif in electronic-based popular music.[52][53]
The town of Lincoln, Maine holds an annual "LoonFest" in Mid-July that coincides with the peak season for loons' reproductive cycle.
^Evers, David C., James D. Paruk, Judith W. Mcintyre and Jack F. Barr. 2010. Common Loon (Gavia immer), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online:https://bna.birds.cornell.edu/bna/species/313
^Piper, W. H.; Evers, D. C.; Meyer, M. W.; Tischler, K. B.; Klich, M. (2000). "Do common loons mate for life?: scientific investigation of a widespread myth.". In McIntyre, J.; Evers, D. C. (eds.).Loons: Old History and New Findings.. pp. 43–49.
^Linnaeus, Carl (1758): 68.1.Colymbus arcticus. In:Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis (10th ed., vol. 1): 190 [Latin book]. Lars Salvius, Stockholm ("Holmius").Digitized version
^Known from a few limb bones. Roughly similar in size toPacific loon, but proportions seem to differ and apparently not close to any living species except maybered-throated loon:Brodkorb (1953).
^A tiny loon, smaller and more delicate than even thesympatric contemporaryG. egeriana-like birds. Probably a distinct species –sexual dimorphism in loons is not very pronounced:Rasmussen (1998).
^Known from a skull very similar to theblack-throated loon. Initially assigned toG. concinna, but this is not very likely:Mlíkovský (2002: p. 64), and see also at"Gavia" portisi.
^Demetracopoulou, D. (1933). "The Loon Woman Myth: A Study in Synthesis".The Journal of American Folklore.46 (180):101–128.doi:10.2307/535774.JSTOR535774.
^Tidemann, Sonia; Gosler, Andrew, eds. (2010).Ethno-ornithology: Birds, Indigenous Peoples, Culture and Society. London: Earthscan. p. 191.ISBN978-1-84407-783-0.
^Stewart, Barry D. (2004):Across The Land: A Canadian Journey Of Discovery. Trafford Publishing.ISBN1-4120-2276-2, p. 143
^Heinrichs, Ann (2003):Minnesota. Compass Point Books.ISBN0-7565-0315-9, p. 44
^Moran, Mark; Sceurman, Mark; Godfrey, Linda S. & Hendricks, Richard D. (2005):Weird Wisconsin: Your Travel Guide to Wisconsin's Local Legends and Best Kept Secrets. Sterling Publishing.ISBN0-7607-5944-8, p. 78
.jpg)
_-_Summer_plumage_breeding_adult2.jpg)
.jpg)
_1APR2017.jpg)
