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The sarus crane (''Antigone antigone'') is a large nonmigratory crane found in parts of the
Indian subcontinent The Indian subcontinent is a physiographic region of Asia below the Himalayas which projects into the Indian Ocean between the Bay of Bengal to the east and the Arabian Sea to the west. It is now divided between Bangladesh, India, and Pakista ...
,
Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...
, and northern
Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
. The tallest of the flying birds, standing at a height of up to , they are a conspicuous species of open
wetland A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...
s in South Asia, seasonally flooded ''
Dipterocarpus '' D. retusus'' in Köhler ''Dipterocarpus'' is a genus of flowering plants and the type genus of family Dipterocarpaceae. ''Dipterocarpus'' is the third-largest and most diverse genus among the Dipterocarpaceae. The species are well known for ...
'' forests in Southeast Asia, and ''
Eucalyptus ''Eucalyptus'' () is a genus of more than 700 species of flowering plants in the family Myrtaceae. Most species of ''Eucalyptus'' are trees, often Mallee (habit), mallees, and a few are shrubs. Along with several other genera in the tribe Eucalyp ...
''-dominated woodlands and grasslands in Australia. The sarus crane is easily distinguished from other cranes in the region by its overall grey colour and the contrasting red head and upper neck. They forage on marshes and shallow wetlands for roots, tubers, insects, crustaceans, and small vertebrate prey. Like other cranes, they form long-lasting
pair bond In biology, a pair bond is the strong affinity that develops in some species between a mating pair, often leading to the production and rearing of young and potentially a lifelong bond. Pair-bonding is a term coined in the 1940s that is frequently ...
s and maintain territories within which they perform territorial and courtship displays that include loud trumpeting, leaps, and dance-like movements. In India, they are considered symbols of marital fidelity, believed to mate for life and pine the loss of their mates, even to the point of starving to death. The main breeding season is during the wet season, when the pair builds an enormous nest "island," a circular platform of reeds and grasses nearly two meters in diameter and high enough to stay above the shallow water surrounding it. Increased agricultural intensity is often thought to have led to declines in sarus crane numbers, but they also benefit from wetland crops and the construction of canals and reservoirs. The stronghold of the species is in India, where it is traditionally revered and lives in agricultural lands in close proximity to humans. Elsewhere, the species has been
extirpated Local extinction, also extirpation, is the termination of a species (or other taxon) in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinctions. Local extinctions mark a chan ...
in many parts of its former range.


Taxonomy

In 1743 the English naturalist George Edwards included an illustration and a description of the sarus crane in the first volume of his ''A Natural History of Uncommon Birds''. He used the English name "The Greater Indian Crane". Edwards based his hand-coloured etching on a live specimen that he had drawn at the London home of the Admiral
Charles Wager Admiral Sir Charles Wager (24 February 1666 – 24 May 1743) was an English Royal Navy officer and politician who served as First Lord of the Admiralty from 1733 to 1742. Despite heroic active service and steadfast administration and diplomatic ...
. When in 1758 the Swedish naturalist
Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...
updated his ''Systema Naturae'' for the tenth edition, he placed the sarus crane (''Grus major Indica'' in Latin) with the herons and cranes in the
genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
'' Ardea''. Linnaeus included a brief description, coined the
binomial name In taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, altho ...
''Ardea antigone'' and cited Edwards' work. The specific epithet is based on
Greek mythology Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of ancient Greek folklore, today absorbed alongside Roman mythology into the broader designation of classical mythology. These stories conc ...
.
Antigone ANTIGONE (Algorithms for coNTinuous / Integer Global Optimization of Nonlinear Equations), is a deterministic global optimization solver for general Mixed-Integer Nonlinear Programs (MINLP). History ANTIGONE is an evolution of GloMIQO, a global ...
was the daughter of the
Trojan Trojan or Trojans may refer to: * Of or from the ancient city of Troy * Trojan language, the language of the historical Trojans Arts and entertainment Music * '' Les Troyens'' ('The Trojans'), an opera by Berlioz, premiered part 1863, part 18 ...
king
Laomedon In Greek mythology, Laomedon (; , ''Lāomédōn'', "ruler of the people") was a Troy, Trojan king, son of Ilus (son of Tros), Ilus and thus nephew of Ganymede (mythology), Ganymede and Assaracus. Laomedon was variously identified with differe ...
. She was turned into a stork for comparing her own beauty with the goddess
Hera In ancient Greek religion, Hera (; ; in Ionic Greek, Ionic and Homeric Greek) is the goddess of marriage, women, and family, and the protector of women during childbirth. In Greek mythology, she is queen of the twelve Olympians and Mount Oly ...
. Linnaeus appears to have confused this myth with that of Gerana, queen of the pigmies, who considered herself more beautiful than Hera and was turned into a crane. The sarus crane was formerly placed in the genus '' Grus'', but a
molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...
study published in 2010 found that the genus, as then defined, was
polyphyletic A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as Homoplasy, homoplasies ...
. In the resulting rearrangement to create
monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...
genera, four species, including the sarus crane, were placed in the resurrected genus ''Antigone'' that had originally been erected by German naturalist
Ludwig Reichenbach Heinrich Gottlieb Ludwig Reichenbach (8 January 1793 – 17 March 1879) was a German botanist, ornithologist and illustrator. It was he who first requested Leopold and Rudolf Blaschka, Leopold Blaschka to make a set of glass marine invertebrate m ...
in 1853.
Edward Blyth Edward Blyth (23 December 1810 – 27 December 1873) was an English zoologist who worked for most of his life in India as a curator of zoology at the Asiatic Society, Royal Asiatic Society of Bengal in Calcutta. He set about updating the museum ...
published a
monograph A monograph is generally a long-form work on one (usually scholarly) subject, or one aspect of a subject, typically created by a single author or artist (or, sometimes, by two or more authors). Traditionally it is in written form and published a ...
on the cranes in 1881, in which he considered the "sarus crane" of India to be made up of two species, ''Grus collaris'' and ''Grus antigone''. Most modern authors recognize one species with three disjunct populations that are sometimes treated as subspecies, although the status of one extinct population from the Philippines is uncertain. The sarus cranes in India (referred to as ''A. a. antigone'') are the largest, and in Myanmar to the east are replaced by a population that extends into Southeast Asia (referred to as ''A. a. sharpii''). Sarus cranes from the Indian subcontinent are differentiated from the south-eastern population by the white collar below their bare head and upper neck, and their white tertiary flight feathers. The population in Australia (initially placed in ''A. a. sharpii'' (sometimes spelt ''sharpei'' but amended to conform to the rules of Latin grammar) was separated and named ''A. a. gilliae,'' sometimes spelt ''gillae'' or ''gillii''), prior to a genetic analysis. A 2005 genetic analysis suggests that these three populations are representatives of a formerly continuous population that varied clinally. The Australian subspecies was designated only in 1988, with the species itself was first noticed in Australia in 1966 and regarded as a recent immigrant. Native Australians, however, differentiated between the sarus and the brolga, calling the sarus "the crane that dips its head in blood.” Sarus cranes of the Australian population are similar to those in Southeast Asia in having no white on the neck and tertiary remiges, but are distinguished by a larger grey patch of ear coverts. The Australian population shows the most recent divergence from the ancestral form with an estimated 3000 generations of breeding within Australia. An additional subspecies, ''A. a. luzonica,'' was suggested for the population — now extinct — in the Philippines. No distinctive characteristic is known of this disappeared population. Analysis of
mitochondrial DNA Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondrion, mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the D ...
from a limited number of specimens suggests that
gene flow In population genetics, gene flow (also known as migration and allele flow) is the transfer of genetic variation, genetic material from one population to another. If the rate of gene flow is high enough, then two populations will have equivalent ...
occurred within the continental Asian populations until the 20th-century reductions in range, and that Australia was colonized only in the
Late Pleistocene The Late Pleistocene is an unofficial Age (geology), age in the international geologic timescale in chronostratigraphy, also known as the Upper Pleistocene from a Stratigraphy, stratigraphic perspective. It is intended to be the fourth division ...
, some 35,000 years ago. This has been corroborated by DNA
microsatellite A microsatellite is a tract of repetitive DNA in which certain Sequence motif, DNA motifs (ranging in length from one to six or more base pairs) are repeated, typically 5–50 times. Microsatellites occur at thousands of locations within an organ ...
analyses on a large and widely distributed set of individuals in the sample. This study suggests further that the Australian population shows low genetic variability. As there exists the possibility of (limited) hybridization with the genetically distinct brolga, the Australian sarus crane can be expected to be an incipient species. The common name 'sarus' is from the Hindi name (''sāras'') for the species. The Hindi word is derived from the
Sanskrit Sanskrit (; stem form ; nominal singular , ,) is a classical language belonging to the Indo-Aryan languages, Indo-Aryan branch of the Indo-European languages. It arose in northwest South Asia after its predecessor languages had Trans-cultural ...
word ''sarasa'' for the "lake bird", (sometimes corrupted to ''sārhans''). British soldiers in colonial India who hunted the birds corrupted the name to ''serious'' or even ''cyrus''.


Description

The adult sarus crane is very large, with grey wings and body, a bare red head, collar and
nape The nape is the back of the neck. In technical anatomical/medical terminology, the nape is also called the nucha (from the Medieval Latin rendering of the Arabic , ). The corresponding adjective is ''nuchal'', as in the term ''nuchal rigidity'' ...
, a greyish
crown A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, parti ...
, and a long, greenish-grey, pointed bill. In flight, the long neck is held straight, unlike that of a
heron Herons are long-legged, long-necked, freshwater and coastal birds in the family Ardeidae, with 75 recognised species, some of which are referred to as egrets or bitterns rather than herons. Members of the genus ''Botaurus'' are referred to as bi ...
(which folds it back), and the black wing tips can be seen; the crane's long, pink legs trail behind them. This bird has a grey ear
covert Secrecy is the practice of hiding information from certain individuals or groups who do not have the "need to know", perhaps while sharing it with other individuals. That which is kept hidden is known as the secret. Secrecy is often controver ...
patch, orange-red irises, and a greenish-grey bill. Juveniles have a yellowish base to the bill and the brown-grey head is fully feathered. The bare red skin of the adult's head and neck is brighter during the breeding season. This skin is rough and covered by feather follicles, and a narrow area around and behind the head is covered by black, bristly feathers. The sexes do not differ in plumage, although males are on average larger than females; males of the Indian population can attain a maximum height around , making them the world's tallest
extant Extant or Least-concern species, least concern is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Exta ...
flying bird. The weight of
nominate race In biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. ...
individuals is , while five adults of ''A. a. sharpii'' averaged . Across the distribution range, their weight can vary from , height typically from , and wingspan from . While individuals from northern populations are among the heaviest cranes, alongside the red-crowned and
wattled crane The wattled crane (''Grus carunculata'') is a large, threatened species of crane found in wetlands and grasslands of eastern and southern Africa, ranging from Ethiopia to South Africa. Some authorities consider it the sole member of the genus ...
s, and the largest in their range, birds from Australia tend to be smaller. In Australia, the sarus can easily be mistaken for the more widespread
brolga The brolga (''Antigone rubicunda''), formerly known as the native companion, is a bird in the crane (bird), crane family. It has also been given the name Australian crane, a term coined in 1865 by well-known ornithology, ornithologist John Gou ...
. The brolga has the red colouring confined to the head and not extending onto the neck. Body mass in Australian sarus cranes was found to average in males and in females, with a range for both sexes of . Thus, Australian sarus cranes average about 25% lighter than the northern counterparts and are marginally lighter on average than brolgas.


Distribution and habitat

The species has historically been widely distributed on the lowlands of India along the Gangetic plains, extending south to the
Godavari River The Godavari (, Help:IPA/Sanskrit, �od̪aːʋəɾiː is India's second longest river after the Ganges River, Ganga River and drains the third largest Drainage basin, basin in India, covering about 10% of India's total geographical area. It ...
, west to coastal
Gujarat Gujarat () is a States of India, state along the Western India, western coast of India. Its coastline of about is the longest in the country, most of which lies on the Kathiawar peninsula. Gujarat is the List of states and union territories ...
, the
Tharparkar District Tharparkar ( Dhatki/; , ), also known as Thar, is a district in Sindh province in Pakistan, headquartered at Mithi. Before Indian independence it was known as the Thar and Parkar (1901⁠–⁠1947) or Eastern Sindh Frontier District (1860⁠– ...
of Pakistan, and east to
West Bengal West Bengal (; Bengali language, Bengali: , , abbr. WB) is a States and union territories of India, state in the East India, eastern portion of India. It is situated along the Bay of Bengal, along with a population of over 91 million inhabi ...
and
Assam Assam (, , ) is a state in Northeast India, northeastern India, south of the eastern Himalayas along the Brahmaputra Valley, Brahmaputra and Barak River valleys. Assam covers an area of . It is the second largest state in Northeast India, nor ...
. The species no longer breeds in
Punjab Punjab (; ; also romanised as Panjāb or Panj-Āb) is a geopolitical, cultural, and historical region in South Asia. It is located in the northwestern part of the Indian subcontinent, comprising areas of modern-day eastern Pakistan and no ...
, though it winters regularly in the state. Sarus cranes are rare in West Bengal and Assam, and are no longer found in the state of
Bihar Bihar ( ) is a states and union territories of India, state in Eastern India. It is the list of states and union territories of India by population, second largest state by population, the List of states and union territories of India by are ...
. In Nepal, its distribution is restricted to the western and central lowland plains, with most of the population occurring in Rupandehi, Kapilvastu, and Nawalparasi districts. Two distinct populations of sarus cranes occur in Southeast Asia: the northern population in China and Myanmar, and the southern population in Cambodia and Vietnam. The sarus used to extend to Thailand and further east into the Philippines, but may now be extinct in both these countries. In 2011, 24 captive-bred cranes raised from five founders were reintroduced into Thailand. A reasonably sized population of over 150 breeding pairs of sarus cranes has been discovered in the Ayeyarwadi delta, Myanmar, with additional cranes confirmed in the states of Kachin, Shan, and Rakhine. In Australia they are found only in the north-east, and are partly migratory in some areas. The global range has shrunk and the largest occupied area, and the largest known population, is in India. Increasing paddy fields accompanied by an increase in the network of irrigation canals during and prior to the Green Revolution may have facilitated increases in the distribution and numbers of sarus cranes due to an increase in reliable moisture levels in various locations in India. Although now found mainly at low elevations on the plains, some historical records exist from highland marshes further north in Harkit Sar and Kahag in
Kashmir Kashmir ( or ) is the Northwestern Indian subcontinent, northernmost geographical region of the Indian subcontinent. Until the mid-19th century, the term ''Kashmir'' denoted only the Kashmir Valley between the Great Himalayas and the Pir P ...
. The sarus crane breeds in some high elevation regions such as near the
Pong Dam The Pong Dam, also known as the Beas Dam, is an earth-fill embankment dam on the Beas River in the state of Himachal Pradesh, India, just upstream of Talwara. The purpose of the dam is water storage for irrigation and hydroelectric power generati ...
in Himachal Pradesh, where populations may be growing in response to increasing rice cultivation along the reservoir. In rice-dominated districts of
Uttar Pradesh Uttar Pradesh ( ; UP) is a States and union territories of India, state in North India, northern India. With over 241 million inhabitants, it is the List of states and union territories of India by population, most populated state in In ...
, sarus crane abundance (estimated as occupancy) was highest in the western districts, intermediate in the central districts, and minimal in the eastern districts. Sarus crane abundance was positively associated with percentage of wetlands on the landscape, and negatively with the percentage of area under rice cultivation. Field surveys and detailed observations of sarus cranes increased greatly in Myanmar by 2022, with a strong focus on the Ayeyarwadi delta. Surveys across multiple townships discovered over 150 pairs of breeding Sarus Cranes (with a maximum of 185 nests monitored in 2018), suggesting that the population in this region is far higher than was previously known. The vast majority of nests were located in rice paddies, with few in flooded grass patches. Until recently, little was known of sarus crane ecology from Australia. Breeding records (confirmed sightings of nests with eggs, or of adult birds with flightless young) were known from only three locations, all in the Gulf Plains in Queensland. Two records are from near Normanton; one of adults with flightless chicks seen about 30 km west of the town and another of adults incubating eggs seen 7-km south of the town. The third record is a one-month study that provides details of 32 nests located within 10-km around Morr Morr cattle station in the Gilbert River floodplains. A 3,000-km survey along the
Gulf of Carpentaria The Gulf of Carpentaria is a sea off the northern coast of Australia. It is enclosed on three sides by northern Australia and bounded on the north by the eastern Arafura Sea, which separates Australia and New Guinea. The northern boundary ...
located 141 territorial, breeding pairs spread out across the floodplains of the Mitchell, Gilbert, and Flinders Rivers. Carefully mapping of breeding areas of sarus cranes in Australia is needed to understand their distribution range. They are uncommon in
Kakadu National Park Kakadu National Park is a protected area in the Northern Territory of Australia, southeast of Darwin. It is a World Heritage Site. Kakadu is also gazetted as a locality, covering the same area as the national park, with 313 people recorded l ...
, where the species is often hard to find among the more numerous brolgas. Flocks in the non-breeding season are commonly seen in the
Atherton Tableland The Atherton Tableland is a fertile plateau, which is part of the Great Dividing Range in Queensland, Australia. It has very deep, rich basaltic soils and the main industry is agriculture. The principal river flowing across the plateau is the B ...
s in northeastern Queensland. In India, sarus cranes preferentially use wetlands for nesting, but also nest in uncultivated patches amid flooded rice paddies (called ''khet-taavadi'' in Gujarat), and in the rice paddies especially when wetlands are not available to breeding pairs. Breeding pairs are territorial and prefer to forage in natural wetlands, though wetland crops such as rice and wheat are also frequented. In south-western Uttar Pradesh, sarus cranes were found in wetlands of all sizes with larger numbers in larger wetlands. In Australia, wintering, nonbreeding sarus cranes forage in areas with intensive agriculture (primarily maize, sugarcane, groundnuts) and smaller patches of cattle-grazing areas in the Atherton Tablelands. They were observed to feed on grain, nuts, and insects from a range of crop fields, including stubble of maize and peanut crops, hay crops, fields with potato, legumes, and seed crops, and after harvest in fields of sugarcane, grass, and fodder crops. Territorial, breeding sarus crane pairs in northern Queensland along the Gulf of Carpentaria use a range of habitats, but preferentially use low, open woodland on quaternary alluvial plains in outer river deltas and levees with a vegetation of '' Lysiphyllum cunninghamii'', '' Eucalyptus microtheca'', '' Corymbia confertiflora'', ''
Melaleuca ''Melaleuca'' () is a genus of nearly 300 species of plants in the myrtle family, Myrtaceae, commonly known as paperbarks, honey-myrtles, bottlebrushes or tea-trees (although the last name is also applied to species of '' Leptospermum''). They ...
'' spp., '' Excoecaria parvifolia'', '' Atalaya hemiglauca'', '' Grevillea striata'', '' Eucalyptus leptophleba'', ''C. polycarpa'', ''C. confertiflora'', and '' C. bella''.


Ecology and behaviour

While many other cranes make long migrations, sarus cranes are largely nonmigratory, although some populations do migrate short distances. In South Asia, four distinct population-level behaviours have been noted: The first is the "wintering population" of a small number of sarus cranes that use wetlands in the state of Punjab during winters. The source of this population is unclear, but is very likely to be from the growing population in Himachal Pradesh. The second is the "expanding population" consisting of cranes appearing in new areas following new irrigation structures in semiarid and arid areas primarily in Gujarat and Rajasthan. The third is the "seasonally migratory" population, also primarily in the arid zone of Gujarat and Rajasthan. Cranes from this population aggregate in remaining wetlands and reservoirs during the dry summer, and breeding pairs set up territories during the rainy season (July – October) remaining on territories throughout the winter (November – March). The fourth population is "perennially resident" and found in areas such as southwestern Uttar Pradesh, where artificial and natural water sources enable cranes to stay in the same location throughout the year. Migratory populations are also known from Southeast Asia and Australia. File:Sarus_Dance_02.jpg, Bowing display File:Sarus_dance_03.jpg, File:A couple of Sarus Crane.jpg File:Sarus_Call_04.jpg, Leap File:Sarus_Call_01.jpg, Unison calling Breeding pairs maintain territories that are defended from other cranes using a large repertoire of calls and displays. In Uttar Pradesh, less than a tenth of the breeding pairs maintain territories at wetlands; the rest of the pairs are scattered in smaller wetlands and agricultural fields. Non-breeding birds form flocks that vary from 1–430 birds. In semi-arid areas, breeding pairs and successfully fledged juveniles depart from territories in the dry season and join non-breeding flocks. In areas with perennial water supply, as in the western plains of Uttar Pradesh, breeding pairs maintain perennial territories. The largest known flocks are from the
Keoladeo National Park Keoladeo National Park, or Keoladeo Ghana National Park, is a national park in Rajasthan, India. The national park hosts thousands of native, resident and migratory birds, especially during the winter season, when many different species fly to t ...
– with as many as 430 birds, and from unprotected, community-owned wetlands in Etawah and Mainpuri districts in Uttar Pradesh, ranging from 245 to 412 birds. Flocks of over 100 birds are also reported from Gujarat in India and Australia. Sarus crane populations in Keoladeo National Park have been noted to drop from over 400 birds in summer to just 20 birds during the monsoon. In areas with perennial wetlands on the landscape, such as in western Uttar Pradesh, numbers of nonbreeding sarus cranes in flocks can be relatively stable throughout the year. In Etawah and Mainpuri districts, nonbreeding sarus cranes constituted up to 65% of the regional population. Breeding pairs in Australia similarly defend territories from neighbouring crane pairs, and nonbreeding birds are found in flocks frequently mixed with brolgas. The most common social units for Sarus cranes are breeding pairs that defend territories within which they raise young, and non-breeding cranes that live in flocks. Paired birds can be recognized by their behaviour of rendering unison calls, or duets, that they use either at the border of their territories towards neighbouring crane pairs, or on the nest when adults change incubation duties, or in response to intrusions of other Sarus cranes into or over their territories. Rarely, Sarus crane pairs allow a third crane into their territories forming trios that render synchronized unison calls termed as "triets". Sarus crane trios are rare (1.6% of 11,591 observed groups) but ubiquitous, are both polyandrous and polygynous, improve breeding success, are seen more in areas that have more non-breeding flocks, and are largely formed in areas with poor quality habitat and territories. Triets are structurally distinct from duets having much lower frequencies and being longer, but it is not known if there is a functional significance for this difference. A single polyandrous trio observed had a young male as the third bird (recognized by coloration of the primaries) which suggests that breeding pairs may allow younger birds into their territories to help raise chicks as trios. The advantage of being in a trio for breeding pairs is clearly improved breeding success and perhaps also additional assistance to defend territories. However, the advantage to third birds is not yet known and is suspected to provide younger cranes with practice in raising chicks and defending territories. Social units of cranes are very poorly studied and it is thought unlikely that trios are only found in Sarus cranes. They roost in shallow water, where they may be safe from some ground predators. Adult birds do not
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 ...
their feathers annually, but feathers are replaced about once every two to three years.


Feeding

Sarus cranes forage in shallow water (usually with less than depth of water) or in fields, frequently probing in mud with their long bills. In the dry season (after breeding), sarus cranes in Anlung Pring Sarus Crane Conservation Area, Cambodia, used wetlands with 8–10 cm of water. They are
omnivorous An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize ...
, eating insects (especially grasshoppers), aquatic plants, fish (perhaps only in captivity), frogs, crustaceans, and seeds. Occasionally tackling larger vertebrate prey such as water snakes (''
Fowlea piscator The checkered keelback (''Fowlea piscator''), also known commonly as the Asiatic water snake, is a common species in the subfamily Natricinae of the family Colubridae. The species is endemic to Asia. It is non-venomous. Description The eye of ' ...
''), sarus cranes may in rare cases feed on the eggs of birds and turtles. Very few instances of sarus crane adults hunting and feeding chicks of other waterbirds are known, with two published observations of adult birds hunting chicks of the Grey-headed Swamphen ''Porphyrio poliocephalus''. In north India, this behaviour appears restricted to around Delhi, and may be a novel habit of one pair that is learnt by chicks who have dispersed to nearby wetlands. Plant matter eaten includes tubers, corms of aquatic plants, grass shoots as well as seeds and grains from cultivated crops such as peanuts and cereal crops such as rice. In the dry season, cranes flocking in Southeast Asian wetlands are in areas with an abundance of ''Eleocharis dulcis'' and ''E. spiralis'', both of which produce tubers on which the cranes are known to feed. In their breeding grounds in north-eastern Australia, isotopic analyses on molted feathers revealed sarus crane diets to comprise a great diversity of vegetation, and restricted to a narrow range of trophic levels.


Courtship and breeding

Sarus cranes have loud, trumpeting calls, which, as in other cranes, are produced by the elongated windpipe that forms coils within the sternal region. Pairs may indulge in spectacular displays of calling in unison and posturing. These include "dancing" movements that are performed both during and outside the breeding season and involve a short series of jumping and bowing movements made as one of the pair circles around the other. Dancing may also be a
displacement activity Displacement activities occur when an animal or human experiences high motivation for two or more conflicting behaviours: the resulting displacement activity is usually unrelated to the competing motivations. Birds, for example, may peck at grass ...
, when the nest or young is threatened. The cranes breed mainly during the monsoons in India (from July to October, although a second brood may occur), and breeding has been recorded in all the months. They build large nests, platforms made of reeds and vegetation in wet marshes or paddy fields. The nest is constructed within shallow water by piling up rushes, straw, grasses with their roots, and mud so that the platform rises above the level of the water to form a little island. The nest is unconcealed and conspicuous, being visible from afar, and defended fiercely by the pair. Data collated over a century from South Asia show sarus cranes nesting throughout the year. More focused observations, however, show nesting patterns to be closely tied to rainfall patterns. An exception to this rule was the unseasonal nesting observed in the artificially flooded Keoladeo-Ghana National Park, and in marshes created by irrigation canals in Kota district of Rajasthan, India. Based on these observations, unseasonal nesting (or nesting outside of the monsoon) of sarus cranes was thought to be due to either the presence of two populations, some pairs raising a second brood, and unsuccessful breeding by some pairs in the normal monsoon season, prompting them to nest again when conditions such as flooded marshes remain. A comprehensive assessment of unseasonal nesting based on collation of over 5,000 breeding records, however, showed that unseasonal nesting by sarus cranes in South Asia was very rare and was only carried out by pairs that did not succeed in raising chicks in the normal nesting season. Unseasonal nests were initiated in years when rainfall extended beyond the normal June–October period, and when rainfall volume was higher than normal; or when artificial wet habitats were created by man-made structures such as reservoirs and irrigation canals to enhance crop production. Nest initiation in northern Queensland is also closely tied to rainfall patterns, with most nests being initiated immediately after the first major rains. The nests can be more than in diameter and nearly high. Pairs show high fidelity to the nest site, often refurbishing and reusing a nest for as many as five breeding seasons. The clutch is one or two eggs (rarely three or four) which are incubated by both sexes for about 31 days (range 26–35 days). Eggs are chalky white and weigh about 240 grams. When disturbed from the nest, parents may sometimes attempt to conceal the eggs by attempting to cover them with material from the edge of the nest. The eggshells are removed by the parents after the chicks hatch either by carrying away the fragments or by swallowing them. About 30% of all breeding pairs succeed in raising chicks in any year, and most of the successful pairs raise one or two chicks each, with brood sizes of three being rare. One survey in Australia found 60% of breeding pairs to have successfully fledged chicks. This high success rate is attributed to above-normal rainfall that year. The chicks are fed by the parents for the first few days, but are able to feed independently after that, and follow their parents for food. When alarmed, the parent cranes use a low ''korr-rr'' call that signals chicks to freeze and lie still. Young birds stay with their parents until the subsequent breeding season. In captivity, birds breed only after their fifth year. The sarus crane is widely believed to pair for life, but cases of "divorce" and mate replacement have been recorded.


Mortality factors

Healthy adult sarus cranes have no predators. However, eggs are often destroyed at the nest by jungle crows (''Corvus macrorhynchos'') and
house crow The house crow (''Corvus splendens''), also known as the Indian, greynecked, Ceylon or Colombo crow, is a common bird of the crow family that is of Asian origin but now found in many parts of the world, where they arrived assisted by shipping. I ...
s (''C. splendens'') in India and Myanmar. In Australia, suspected predators of young birds include the
dingo The dingo (either included in the species ''Canis familiaris'', or considered one of the following independent taxa: ''Canis familiaris dingo'', ''Canis dingo'', or ''Canis lupus dingo'') is an ancient (basal (phylogenetics), basal) lineage ...
(''Canis dingo'') and fox (''Vulpes vulpes''), while
brahminy kite The brahminy kite (''Haliastur indus''), also known as the red-backed sea-eagle in Australia, is a medium-sized bird of prey in the family Accipitridae, which also includes many other diurnal Bird of prey, raptors, such as eagles, buzzards, and h ...
s (''Haliastur indus'') have been known to take eggs. Removal of eggs by farmers (to reduce crop damage) or children (in play), or by migrant labourers for food, or opportunistic egg collection during trips to collect forest resources are prominent causes of egg mortality. Between 31 and 100% of nests with eggs can fail to hatch eggs for these reasons. Chicks are also prone to predation (estimated at 8%) and collection at the nest, but more than 30% die of unknown reasons. Breeding success (percentage of eggs hatching and surviving to fledging stage) has been estimated to be about 20% in Gujarat and 51–58% in south-western Uttar Pradesh. In areas where farmers are tolerant, nests in flooded rice fields and those in wetlands have similar rates of survival. Pairs that nest later in the season have a lower chance of raising chicks successfully, but this improves when territories have more wetlands. Nest success (percentage of nests in which at least one egg hatched) for 96 sarus nests that were protected by locals during 2009–2011 via a payment-for-conservation program was 87% in Cambodia. Nest success of nests monitored with the active participation of farmers in Myanmar was very high (323 out of 356 nests observed between 2016 and 2018 were successful), though chick survival has not yet been measured in Myanmar. More pairs are able to raise chicks in years with higher total rainfall, and when territory quality was undisturbed due to increased farming or development. Permanent removal of pairs from the population due to developmental activities caused reduced population viability, and was a far more important factor impacting breeding success relative to total annual rainfall. Breeding success in Australia has been estimated by counting the proportion of young-of-the-year in wintering flocks in the crop fields of Atherton Tablelands. Young birds constituted 5.32% to 7.36% of the wintering population between 1997 and 2002. It is not known if this variation represents annual differences in conditions in the breeding areas or if it included biases such as different proportions of breeding pairs traveling to the Atherton Tablelands to over-winter. It is also not known how these proportions equate to more standard metrics of breeding success such as proportions of breeding pairs succeeding in raising young birds. One multi-floodplain survey in Australia found 60% of all breeding pairs to have raised at least one chick, with 34% of successful pairs fledging two chicks each. Little is known about the diseases and parasites of the sarus crane, and their effects on wild bird populations. A study conducted at the Rome zoo noted that these birds were resistant to
anthrax Anthrax is an infection caused by the bacterium '' Bacillus anthracis'' or ''Bacillus cereus'' biovar ''anthracis''. Infection typically occurs by contact with the skin, inhalation, or intestinal absorption. Symptom onset occurs between one ...
. Endoparasites that have been described include a
trematode Trematoda is a Class (biology), class of flatworms known as trematodes, and commonly as flukes. They are obligate parasite, obligate Endoparasites, internal parasites with a complex biological life cycle, life cycle requiring at least two Host ( ...
, ''Opisthorhis dendriticus'' from the liver of a captive crane at the London zoo and a Cyclocoelid (''Allopyge antigones'') from an Australian bird. Like most birds, they have bird lice and the species recorded include ''Heleonomus laveryi'' and ''Esthiopterum indicum''. In captivity, sarus cranes have been known to live for as long as 42 years.Flower (1938) notes only 26 years in captivity Premature adult mortality is often the result of human actions. Accidental poisoning by monocrotophos,
chlorpyrifos Chlorpyrifos (CPS), also known as chlorpyrifos ethyl, is an organophosphate pesticide that has been used on crops, animals, in buildings, and in other settings, to kill several pests, including insects and worms. It acts on the nervous systems ...
and
dieldrin Dieldrin is an organochlorine compound originally produced in 1948 by J. Hyman & Co, Denver, as an insecticide. Dieldrin is closely related to aldrin, which reacts further to form dieldrin. Aldrin is not toxic to insects; it is oxidized in the i ...
-treated seeds used in agricultural areas has been noted. Adults have been known to fly into power lines and die of electrocution, this is responsible for killing about 1% of the local population each year.


Conservation status

An estimated 15,000–20,000 mature sarus cranes were left in the wild in 2009. The most robust of the three subspecies, the Indian population numbers fewer than 10,000. Sarus cranes are considered sacred, and the birds are traditionally unharmed. In many areas, they are unafraid of humans. They used to be found on occasion in
Pakistan Pakistan, officially the Islamic Republic of Pakistan, is a country in South Asia. It is the List of countries and dependencies by population, fifth-most populous country, with a population of over 241.5 million, having the Islam by country# ...
, but have not been seen there since the late 1980s. Estimates of the global population have assumed that, due to expansion of agriculture, the population in 2000 was at best about 10% and at the worst just 2.5% of the numbers that existed in 1850. This assumption has been challenged and evidence shows that the population of Sarus cranes increased greatly during and after the Green Revolution in India when a large number of irrigation canals were constructed, which in turn supports both increased breeding and spreading of Sarus cranes. Additionally, emerging evidence from both Nepal and India show agriculture to be conducive for Sarus crane breeding contrary to the unsubstantiated assumptions made while suggesting population declines. Many farmers in India believe that these cranes damage standing crops, particularly rice, although studies show that direct feeding on rice grains resulted in losses amounting to less than 1% and trampling could account for grain loss around . The attitude of farmers tends to be positive in spite of these damages, and this has helped in conserving the species within agricultural areas. The role of rice paddies and associated irrigation structures may be particularly important for the birds' conservation, considering that natural wetlands are increasingly threatened by human activity. The conversion of wetlands to farmland, and farmland to more urban uses are major causes for habitat loss and long-term population decline. Compensating farmers for crop losses has been suggested as a helpful measure, but needs to be implemented judiciously so as not to corrupt and remove existing local traditions of tolerance. Farmers in Sarus crane wintering areas in Australia are beginning to use efficient methods to harvest crops, which may lead to lowered food availability. Farmers are also transitioning from field crops to perennial and tree crops that have higher returns. This may reduce available foraging habitat for cranes, and may increase conflict with farmers in the remaining crop fields. Literature pertaining to the abundance of Sarus cranes in Nepal suggests that past field methods were either inadequate or incomplete, and could not yield proper abundance estimates, and that the population of cranes in Nepal might be on the increase. The Australian population is greater than 5,000 birds with record breeding success estimates that suggest that their population might be increasing. The Southeast Asian population, however, has been decimated by war and habitat change (such as intensive agriculture, deforestation, and draining of wetlands), and by the mid-20th century, had disappeared from large parts of its range, which once stretched north to southern China. Recent surveys and detailed field work in Myanmar has shown the breeding population and breeding success to be high indicating that population estimates for south-east Asia require to be revised upwards of the existing estimate of 500–1,500. Multiple institutions are now working in Myanmar alongside farmers, nature clubs, and other enthusiasts to increase awareness on Sarus Crane conservation, and to monitor critical aspects of ecology of the species such as breeding success and mapping distributions. The situation in Myanmar appears to be similar to India and Nepal where farming cycles and farmer attitudes are conducive to Sarus Cranes, with healthy populations being widespread in both locations. Payment to locals to guard nests and help increase breeding success has been attempted in northern Cambodia. Nest success of protected nests was significantly higher than that of unprotected nests, and positive population-level impacts were apparent. However, the program also caused local jealousies leading to deliberate disturbance of nests, and did nothing to alleviate larger-scale and more permanent threats due to habitat losses leading to the conclusion that such payment-for-conservation programs are at best a short-term complement, and not a substitute, to more permanent interventions that include habitat preservation. The little-known Philippine population became extinct in the late-1960s. The sarus crane is classified as vulnerable on the
IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...
. Threats listed include habitat destruction and/or degradation, hunting and collecting, and environmental pollution, and possibly diseases or competing species. The effects of inbreeding in the Australian population, once thought to be a significant threat due to hybridization with brolgas producing hybrid birds called "sarolgas,” is now confirmed to be minimal, suggesting that it is not a major threat. New plans for developing the floodplain areas of northern Queensland may have detrimental impacts on breeding sarus crane population, and require consideration of the needs of cranes, such conservation of a diversity of habitats that are currently found in the region. Emerging evidence from south Asia (Nepal and India), Myanmar and Australia suggests that the species is likely not as threatened as assumed before, and that human activities in these countries (floodplain, small-holder farming and cattle raising) supports a substantial and healthy breeding population of Sarus Cranes. The species has been
extirpated Local extinction, also extirpation, is the termination of a species (or other taxon) in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinctions. Local extinctions mark a chan ...
in Malaysia and the Philippines. Reintroduction programs in Thailand have made use of birds from Cambodia. , attempts to reintroduce the birds to eastern Thailand have shown some promise.


In culture

The species is venerated in India, and legend has it that the poet
Valmiki Valmiki (; , ) was a legendary poet who is celebrated as the traditional author of the epic ''Ramayana'', based on the attribution in the text itself. He is revered as ''Ādi Kavi'', the first poet, author of ''Ramayana'', the first epic poe ...
cursed a hunter for killing a sarus crane and was then inspired to write the epic
Ramayana The ''Ramayana'' (; ), also known as ''Valmiki Ramayana'', as traditionally attributed to Valmiki, is a smriti text (also described as a Sanskrit literature, Sanskrit Indian epic poetry, epic) from ancient India, one of the two important epics ...
. The species was a close contender to the
Indian peafowl The Indian peafowl (''Pavo cristatus''), also known as the common peafowl, or blue peafowl, is a peafowl species native to the Indian subcontinent. While it originated in the Indian subcontinent, it has since been introduced to many other part ...
as the national bird of India. Among the
Gondi people The Gondi (Gōṇḍī) or Gond people, who refer to themselves as "Kōītōr" (Kōī, Kōītōr), are an ethnolinguistic group in India. Their native language, Gondi language, Gondi, belongs to the Dravidian languages, Dravidian family. They ...
, the tribes classified as "five-god worshippers" consider the sarus crane as sacred. The meat of the sarus was considered taboo in ancient Hindu scriptures. The sarus crane is widely thought to pair for life, and death of one partner is thought to lead to the other pining to death. They are a symbol of marital virtue and in parts of Gujarat, taking a newlywed couple to see a pair of sarus cranes is customary. Although venerated and protected by Indians, these birds were hunted during the colonial period. Killing a bird would lead to its surviving partner trumpeting for many days, and the other was traditionally believed to starve to death. Even sport-hunting guides discouraged shooting these birds. According to 19th-century British zoologist Thomas C. Jerdon, young birds were good to eat, while older ones were "worthless for the table.” Eggs of the sarus crane are, however, used in folk remedies in some parts of India. Young birds were often captured and kept in menageries, both in India and in Europe in former times. They were also successfully bred in captivity early in the 17th century by Emperor Jehangir, who noted that the eggs were laid with an interval of two days, and the incubation period lasted 34 days. They were also bred in zoos in Europe and the United States in the early 1930s. The Indian state of Uttar Pradesh declared the sarus crane as its official state bird in 2013. An Indian 14-seater propeller aircraft, the Saras, is named after this crane.


Notes


References


Other sources

* Matthiessen, Peter & Bateman, Robert (2001). ''The Birds of Heaven: Travels with Cranes''. North Point Press, New York. * * * * *


External links

* International Crane Foundation
Sarus Crane, ''Grus antigone''
Retrieved 22 February 2007. *
USGS The United States Geological Survey (USGS), founded as the Geological Survey, is an government agency, agency of the United States Department of the Interior, U.S. Department of the Interior whose work spans the disciplines of biology, geograp ...
Northern Prairie Wildlife Research Center
The Cranes Status Survey and Conservation Action Plan: Sarus Crane (''Grus antigone'')
Retrieved 22 February 2007.




Sarus Crane (''Grus antigone'')
from ''Cranes of the World'' (1983) by
Paul Johnsgard Paul Austin Johnsgard (28 June 1931 – 28 May 2021) was an ornithologist, artist and emeritus professor at the University of Nebraska. His works include nearly fifty books including several monographs, principally about the waterfowl and cranes. ...

Arkive
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sarus crane The sarus crane (''Antigone antigone'') is a large nonmigratory Crane (bird), crane found in parts of the Indian subcontinent, Southeast Asia, and northern Australia. The tallest of the flying birds, standing at a height of up to , they are a c ...
Birds of Cambodia Birds of Myanmar Birds of South Asia Birds of Queensland Fauna of South Asia Vulnerable fauna of Australia
sarus crane The sarus crane (''Antigone antigone'') is a large nonmigratory Crane (bird), crane found in parts of the Indian subcontinent, Southeast Asia, and northern Australia. The tallest of the flying birds, standing at a height of up to , they are a c ...
Articles containing video clips Taxa named by Carl Linnaeus Symbols of Uttar Pradesh