Kagu
Encyclopedia
The Kagu or Cagou is a crested, long-legged, and bluish-grey bird endemic to the dense mountain forests of New Caledonia
. It is the only surviving member of the genus
Rhynochetos and the family Rhynochetidae, although a second species has been described from the fossil
record. Measuring 55 cm (21.7 in) in length, it has pale grey plumage
and bright red legs. Its 'nasal corns' are a unique feature not shared with any other bird. Almost flightless, it a spends its time on or near the ground, where it hunts its invertebrate prey, and builds a nest
of sticks on the forest floor. Both parents share incubation of single egg
, as well as rearing the chick. It has proved vulnerable to introduced predators, and is threatened with extinction.
The Kagu's affinities are not too well resolved. It was long one of the most enigmatic birds and in more recent times usually affiliated with the Gruiformes
. It was initially classed as a member of the family Ardeidae because of its powder down, and an affinity with the Ardeidae is suggested by some morphological as well as DNA-DNA hybridization data. The case for this is not strengthened by more recent data however.
When seen as a gruiform, the Kagu is generally considered related to the extinct adzebill
s from New Zealand
and the Sunbittern
from Central
and South America
. Recent studies do indicate that the Sunbittern is the closest living relative of the Kagu. For example, Fain & Houde found these to be certainly sister taxa. They and the mesite
s did not group with traditional Gruiformes in their study, but instead with their proposed clade
Metaves, which also includes the Hoatzin
, pigeons, Caprimulgiformes
, flamingos, tropicbirds, Apodiformes
, sandgrouse
and grebes. The internal structure of this group was not well resolvable by their data, and contains numerous groupings which are almost certainly incorrect (such as Caprimulgidae and flamingos). Thus, the entire "Metaves" may be nothing more than a collection of lineages united by molecular homoplasies. Nonwithstanding, the Kagu and Sunbittern – and possibly the adzebills – seem to form a distinct Gondwana
n lineage of birds, possibly one order, possibly more, even though the relationships between them, the mesites, and the "core Gruiformes" are not yet resolved. It is notable, however, that the Sunbittern and the mesites possess powder down too, whereas the "core Gruiformes" do not.
While the Kagu is the only living species in the family Rhynochetidae, a larger species of kagu, Rhynochetos orarius, has been described from Holocene
subfossil
remains. The measurements of this species were 15% bigger than Rhynochetos jubatus, with no overlap in measurements except those of the forelimbs. Given that the sites where R. orarius were all lowland sites, and that no fossils of R. jubatus were found in these sites, the scientists that described the fossils suggested they represented highland and lowland species respectively. R. orarius is one of many species to have become extinct in New Caledonia after the arrival of humans. The validity of the species has been questioned by some authors, but accepted by others.
rhis meaning nose and chetos meaning corn, referring to the corn-shaped flaps over the nostrils. The specific name jubatus is derived from the Latin
iabatus meaning crested. The name kagu is derived from the Melanesian
names for the species. The species is variously known as the kavu or kagou in the Kanak languages
, and as the cagou in French (also used as an alternative spelling in English).
is unusually bright for a bird of the forest floor; ash-grey and white coloured. There is little sexual dimorphism
beyond a difference in the amount of barring in the primary feathers. It possesses powder downs which help keep it dry and insulate
it in the extremes of New Caledonia's tropical climate. The crest, which is used to display to other members of the species, is barely noticeable when at rest but can be erected and fanned out. It is nearly flightless, using its wings for displays (its primary wing feathers are patterned), and for moving quickly through the forest. It can also use them to glide when fleeing danger. The wings are not reduced in size like some other flightless birds, and have a span of around 77.5 cm (30.5 in), but they lack the musculature for flight. It possesses bright red legs which are long and strong, enabling the bird to travel long distances on foot and run quickly. It has large eyes, positioned so that they give good binocular vision
which is helpful in finding prey in the leaf litter and seeing in the gloom of the forest. It possesses 'nasal corns', structures covering its nostrils, which are a feature not shared by any other bird. These are presumed to prevent particles entering the nostrils when probing in soil during feeding. Another unique characteristic of the species is that has only one-third the red blood cell
s and three times the hemoglobin
per RBC compared to the usual situation in birds.
Kagus make a range of different sounds, most commonly duetting in the morning, each duet lasting about 15 minutes.
s and shrubland
of New Caledonia and New Guinea. Within that island group it is restricted to the main island of Grande Terre. There is no evidence that it occurred on the Loyalty Islands
, although fossil remains of the extinct lowland form R. orarius have been found on the Ile des Pines
. The Kagu is a habitat generalist and able to exist in a range of different forest types if sufficient prey is present, from rain forest
to drier lowland forest. They are also able to feed in some drier shrubland associated with the island's ultrabasic rocks, although not the low prey poor shrubland of this type. They are also absent from areas where extensive ground cover makes foraging difficult, such as grassland or areas with high fern cover, but may pass through such areas to reach other foraging areas. The species has undergone some range contraction due to hunting and predation by introduced species
. Its original, pre-human distribution, and the extent to which is and its sister species R. orarius coexisted in lowland areas of New Caledonia, is still not fully understood and awaits further research into the subfossil record.
, maintaining year-round territories of around 10-28 hectare
s (22-62 acres). Within the territory the pairs are solitary during the non-breeding season, and may have separate but overlapping foraging areas. The Kagu's crest and wings are used in territorial displays towards other Kagu, slightly different displays are used towards potential predators. Territorial disputes may be resolved by fighting using wings and bills, in the wild this seldom results in serious injuries.
s, snail
s and lizard
s being amongst the most important prey items. Also taken are larvae, spiders, centipedes and insects such as grasshopper
s, bugs, and beetle
s. The majority of the diet is obtained from the leaf litter or soil, with other prey items found in vegetation, old logs and rocks. Sometimes Kagus will hunt small animals in shallow water. Their hunting technique is to stand motionless on the ground or from an elevated perch, and silently watch for moving prey. They may stand on one foot and gently move the leaf litter with the other foot in order to flush prey. Having located prey they will move towards the prey and stand over it, ready to strike, or make a dash towards the prey from their watching location. If digging is required to obtain the prey this is done with the bill, the feet are not used to dig or scratch away debris.
, generally forming long-term pair bonds that are maintained for many years, even possibly life. Kagu can be long lived, with birds in captivity living for over 20 years. A single nesting attempt is made each year, although should the first nesting attempt fail a second attempt is made that year. A simple nest
is constructed, which is little more than a heaped pile of leaves, although in some cases the egg
may be laid directly on the ground. The nest
is not concealed but is usually adjacent to a tree trunk, log or low vegetation. A single grey slightly blotched egg is laid which weighs 60-75 g. Incubation
duties are shared by the parents. Each bird will incubate the egg for 24 hours, with the changeover occurring around noon each day. During each incubation stint the parent will remain on the egg the whole time except early in the morning, when the bird will briefly move away to call to its mate and occasionally forage quickly. The incubation period lasts for 33–37 days, which is long for the size of the egg. Offspring may remain in their parents' territory for many years after fledging
, sometimes up to six years. These chicks do not help in incubating the eggs or raising the chicks, but nevertheless improve the breeding success of the parents. The older offspring do apparently help in territory defence, responding to playback of rivals and also participating in territorial fights, and it has been suggested that this should be treated as a form of cooperative breeding.
in the north of Grande Terre it plays a role in tribal traditions, with its name being given to people, its crest being used in the head-dresses of chiefs, and its calls being incorporated into war dances. The calls of the Kagu were considered messages to be interpreted by the chiefs. Kanaks in the vicinity of Houaïlou
referred to the species as the "ghost of the forest".
The species was not discovered by European scientists until the French colonisation of New Caledonia in 1852 and was not described until a specimen was brought to the Colonial Exhibition
in Paris in 1860. This led to a surge in scientific interest in the species, which resulted in many birds being trapped for museums and zoos. The species was also trapped for food, and was considered a delicacy by European colonisers. It was also fashionable to own Kagus as pets. A campaign was run between 1977-1982 to phase out the pet trade. Today Kagus are considered very important in New Caledonia; they are a high profile endemic
emblem for the Territory. Its distinctive song used to be played to the nation every night as the island's TV station signed off the air. Its survival is considered important for the nation's economy and image.
, pig
s and dog
s. The bird was hunted for its prized crest feathers for use in hats in the 19th century. The species was also trapped extensively for museums and zoos prior to being afforded protection. New Caledonia lacked mammals prior to the arrival of humans (except for bats), and many insular species have been negatively impacted by introduced mammals. Rats have a big impact on nestlings, accounting for 55% of nestling losses. The first concrete evidence for the effect of dogs came when a New Zealand researcher's study population was quickly exterminated by dogs in the 1990s, although suspicions about the importance of dogs and other predators had been voiced prior to this and dog control measures had been enacted in some areas in the 1980s. Its initial decline was caused by subsistence hunting
, and by capture as pet
s. They also suffer from habitat loss, caused by mining
and forestry
. The Kagu is listed as endangered (CITES I), and enjoys full protection in New Caledonia. It has been the subject of highly dedicated conservation
efforts, and is receptive to ex-situ conservation
, breeding well in Nouméa Zoo. It is also prospering in Rivière Bleue Territorial Park, which has a pest
management programme and has been the site of releases into the wild of the captive bred birds.
New Caledonia
New Caledonia is a special collectivity of France located in the southwest Pacific Ocean, east of Australia and about from Metropolitan France. The archipelago, part of the Melanesia subregion, includes the main island of Grande Terre, the Loyalty Islands, the Belep archipelago, the Isle of...
. It is the only surviving member of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Rhynochetos and the family Rhynochetidae, although a second species has been described from the fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
record. Measuring 55 cm (21.7 in) in length, it has pale grey plumage
Plumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
and bright red legs. Its 'nasal corns' are a unique feature not shared with any other bird. Almost flightless, it a spends its time on or near the ground, where it hunts its invertebrate prey, and builds a nest
Nest
A nest is a place of refuge to hold an animal's eggs or provide a place to live or raise offspring. They are usually made of some organic material such as twigs, grass, and leaves; or may simply be a depression in the ground, or a hole in a tree, rock or building...
of sticks on the forest floor. Both parents share incubation of single egg
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
, as well as rearing the chick. It has proved vulnerable to introduced predators, and is threatened with extinction.
Classification
Gruiformes
The Gruiformes are an order containing a considerable number of living and extinct bird families, with a widespread geographical diversity. Gruiform means "crane-like"....
. It was initially classed as a member of the family Ardeidae because of its powder down, and an affinity with the Ardeidae is suggested by some morphological as well as DNA-DNA hybridization data. The case for this is not strengthened by more recent data however.
When seen as a gruiform, the Kagu is generally considered related to the extinct adzebill
Adzebill
The adzebills, genus Aptornis, were two closely related bird species, the North Island Adzebill, Aptornis otidiformis, and the South Island Adzebill, Aptornis defossor, of the extinct family Aptornithidae. The family was endemic to New Zealand.They have been placed in the Gruiformes but this is not...
s from New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
and the Sunbittern
Sunbittern
The Sunbittern, Eurypyga helias is a bittern-like bird of tropical regions of the Americas, and the sole member of the family Eurypygidae and genus Eurypyga.-Description and reproduction:...
from Central
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
and South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
. Recent studies do indicate that the Sunbittern is the closest living relative of the Kagu. For example, Fain & Houde found these to be certainly sister taxa. They and the mesite
Mesite
The mesites are a family of birds of uncertain affinities. They are smallish, near flightless birds endemic to Madagascar. Generally brownish with paler undersides, they are of somewhat pheasant-like appearance and were initially placed with the Galliformes...
s did not group with traditional Gruiformes in their study, but instead with their proposed clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
Metaves, which also includes the Hoatzin
Hoatzin
The Hoatzin , also known as the Hoactzin, Stinkbird, or Canje Pheasant, is a species of tropical bird found in swamps, riverine forest and mangrove of the Amazon and the Orinoco delta in South America...
, pigeons, Caprimulgiformes
Caprimulgiformes
The Caprimulgiformes is an order of birds that includes a number of birds with global distribution . They are generally insectivorous and nocturnal...
, flamingos, tropicbirds, Apodiformes
Apodiformes
Traditionally, the bird order Apodiformes contained three living families: the swifts , the tree swifts , and the hummingbirds . In the Sibley-Ahlquist taxonomy, this order is raised to a superorder Apodimorphae in which hummingbirds are separated as a new order, Trochiliformes...
, sandgrouse
Sandgrouse
The sandgrouse are a family, Pteroclididae, of 16 bird species, the only living members of the order Pteroclidiformes. They are restricted to treeless open country in the Old World, such as plains and semi-deserts. They are distributed across northern, southern and eastern Africa as well as...
and grebes. The internal structure of this group was not well resolvable by their data, and contains numerous groupings which are almost certainly incorrect (such as Caprimulgidae and flamingos). Thus, the entire "Metaves" may be nothing more than a collection of lineages united by molecular homoplasies. Nonwithstanding, the Kagu and Sunbittern – and possibly the adzebills – seem to form a distinct Gondwana
Gondwana
In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinents that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago . Gondwana is believed to have sutured between ca. 570 and 510 Mya,...
n lineage of birds, possibly one order, possibly more, even though the relationships between them, the mesites, and the "core Gruiformes" are not yet resolved. It is notable, however, that the Sunbittern and the mesites possess powder down too, whereas the "core Gruiformes" do not.
While the Kagu is the only living species in the family Rhynochetidae, a larger species of kagu, Rhynochetos orarius, has been described from Holocene
Holocene
The Holocene is a geological epoch which began at the end of the Pleistocene and continues to the present. The Holocene is part of the Quaternary period. Its name comes from the Greek words and , meaning "entirely recent"...
subfossil
Subfossil
Subfossil refers to remains whose fossilization process is not complete, either for lack of time or because the conditions in which they were buried were not optimal for fossilization....
remains. The measurements of this species were 15% bigger than Rhynochetos jubatus, with no overlap in measurements except those of the forelimbs. Given that the sites where R. orarius were all lowland sites, and that no fossils of R. jubatus were found in these sites, the scientists that described the fossils suggested they represented highland and lowland species respectively. R. orarius is one of many species to have become extinct in New Caledonia after the arrival of humans. The validity of the species has been questioned by some authors, but accepted by others.
Etymology
The generic name, Rhynochetos, and the family name Rhynochetidae, are derived from the GreekAncient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
rhis meaning nose and chetos meaning corn, referring to the corn-shaped flaps over the nostrils. The specific name jubatus is derived from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
iabatus meaning crested. The name kagu is derived from the Melanesian
Melanesian languages
The Melanesian languages are the indigenous languages of Melanesia. They include about 400 Austronesian languages and numerous families of Papuan languages....
names for the species. The species is variously known as the kavu or kagou in the Kanak languages
New Caledonian languages
The thirty New Caledonian languages form a branch of the Southern Oceanic languages. Their speakers are known as Kanaks.-Components:*Haekic*Northern New Caledonian**Central Northern: Cemuhî, Paicî...
, and as the cagou in French (also used as an alternative spelling in English).
Description
The Kagu is a ground-living bird, 55 cm (21.7 in) in length. The weight can vary considerably by individual and by season, ranging from 700 to 1100 g (24.7 to 38.8 oz). Its plumagePlumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
is unusually bright for a bird of the forest floor; ash-grey and white coloured. There is little sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
beyond a difference in the amount of barring in the primary feathers. It possesses powder downs which help keep it dry and insulate
Thermal insulation
Thermal insulation is the reduction of the effects of the various processes of heat transfer between objects in thermal contact or in range of radiative influence. Heat transfer is the transfer of thermal energy between objects of differing temperature...
it in the extremes of New Caledonia's tropical climate. The crest, which is used to display to other members of the species, is barely noticeable when at rest but can be erected and fanned out. It is nearly flightless, using its wings for displays (its primary wing feathers are patterned), and for moving quickly through the forest. It can also use them to glide when fleeing danger. The wings are not reduced in size like some other flightless birds, and have a span of around 77.5 cm (30.5 in), but they lack the musculature for flight. It possesses bright red legs which are long and strong, enabling the bird to travel long distances on foot and run quickly. It has large eyes, positioned so that they give good binocular vision
Binocular vision
Binocular vision is vision in which both eyes are used together. The word binocular comes from two Latin roots, bini for double, and oculus for eye. Having two eyes confers at least four advantages over having one. First, it gives a creature a spare eye in case one is damaged. Second, it gives a...
which is helpful in finding prey in the leaf litter and seeing in the gloom of the forest. It possesses 'nasal corns', structures covering its nostrils, which are a feature not shared by any other bird. These are presumed to prevent particles entering the nostrils when probing in soil during feeding. Another unique characteristic of the species is that has only one-third the red blood cell
Red blood cell
Red blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...
s and three times the hemoglobin
Hemoglobin
Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates, with the exception of the fish family Channichthyidae, as well as the tissues of some invertebrates...
per RBC compared to the usual situation in birds.
Kagus make a range of different sounds, most commonly duetting in the morning, each duet lasting about 15 minutes.
Distribution and habitat
The Kagu is endemic to the forestForest
A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...
s and shrubland
Shrubland
Shrubland, scrubland, scrub or brush is a plant community characterized by vegetation dominated by shrubs, often also including grasses, herbs, and geophytes. Shrubland may either occur naturally or be the result of human activity...
of New Caledonia and New Guinea. Within that island group it is restricted to the main island of Grande Terre. There is no evidence that it occurred on the Loyalty Islands
Loyalty Islands
The Loyalty Islands are an archipelago in the Pacific. They are part of the French territory of New Caledonia, whose mainland is away. They form the Loyalty Islands Province , one of the three provinces of New Caledonia...
, although fossil remains of the extinct lowland form R. orarius have been found on the Ile des Pines
Isle of Pines, New Caledonia
The Isle of Pines is an island located in the Pacific Ocean, in the archipelago of New Caledonia, an overseas territory of France. The island is part of the commune of L'Île-des-Pins, in the South Province of New Caledonia. The Isle of Pines is nicknamed l'île la plus proche du paradis...
. The Kagu is a habitat generalist and able to exist in a range of different forest types if sufficient prey is present, from rain forest
New Caledonia rain forests
The New Caledonia rain forests are a terrestrial ecoregion, located in New Caledonia in the South Pacific. It is a tropical moist broadleaf forest ecoregion, part of the Australasia ecozone.-Setting:...
to drier lowland forest. They are also able to feed in some drier shrubland associated with the island's ultrabasic rocks, although not the low prey poor shrubland of this type. They are also absent from areas where extensive ground cover makes foraging difficult, such as grassland or areas with high fern cover, but may pass through such areas to reach other foraging areas. The species has undergone some range contraction due to hunting and predation by introduced species
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
. Its original, pre-human distribution, and the extent to which is and its sister species R. orarius coexisted in lowland areas of New Caledonia, is still not fully understood and awaits further research into the subfossil record.
Behaviour
Kagu are territorialTerritory (animal)
In ethology the term territory refers to any sociographical area that an animal of a particular species consistently defends against conspecifics...
, maintaining year-round territories of around 10-28 hectare
Hectare
The hectare is a metric unit of area defined as 10,000 square metres , and primarily used in the measurement of land. In 1795, when the metric system was introduced, the are was defined as being 100 square metres and the hectare was thus 100 ares or 1/100 km2...
s (22-62 acres). Within the territory the pairs are solitary during the non-breeding season, and may have separate but overlapping foraging areas. The Kagu's crest and wings are used in territorial displays towards other Kagu, slightly different displays are used towards potential predators. Territorial disputes may be resolved by fighting using wings and bills, in the wild this seldom results in serious injuries.
Feeding
The Kagu is exclusively carnivorous, feeding on a variety of animals with annelid wormAnnelid
The annelids , formally called Annelida , are a large phylum of segmented worms, with over 17,000 modern species including ragworms, earthworms and leeches...
s, snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...
s and lizard
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
s being amongst the most important prey items. Also taken are larvae, spiders, centipedes and insects such as grasshopper
Grasshopper
The grasshopper is an insect of the suborder Caelifera in the order Orthoptera. To distinguish it from bush crickets or katydids, it is sometimes referred to as the short-horned grasshopper...
s, bugs, and beetle
Beetle
Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...
s. The majority of the diet is obtained from the leaf litter or soil, with other prey items found in vegetation, old logs and rocks. Sometimes Kagus will hunt small animals in shallow water. Their hunting technique is to stand motionless on the ground or from an elevated perch, and silently watch for moving prey. They may stand on one foot and gently move the leaf litter with the other foot in order to flush prey. Having located prey they will move towards the prey and stand over it, ready to strike, or make a dash towards the prey from their watching location. If digging is required to obtain the prey this is done with the bill, the feet are not used to dig or scratch away debris.
Breeding
Kagus are monogamous breedersMonogamy
Monogamy /Gr. μονός+γάμος - one+marriage/ a form of marriage in which an individual has only one spouse at any one time. In current usage monogamy often refers to having one sexual partner irrespective of marriage or reproduction...
, generally forming long-term pair bonds that are maintained for many years, even possibly life. Kagu can be long lived, with birds in captivity living for over 20 years. A single nesting attempt is made each year, although should the first nesting attempt fail a second attempt is made that year. A simple nest
Bird nest
A bird nest is the spot in which a bird lays and incubates its eggs and raises its young. Although the term popularly refers to a specific structure made by the bird itself—such as the grassy cup nest of the American Robin or Eurasian Blackbird, or the elaborately woven hanging nest of the...
is constructed, which is little more than a heaped pile of leaves, although in some cases the egg
Bird egg
Bird eggs are laid by females and incubated for a time that varies according to the species; a single young hatches from each egg. Average clutch sizes range from one to about 17...
may be laid directly on the ground. The nest
Bird nest
A bird nest is the spot in which a bird lays and incubates its eggs and raises its young. Although the term popularly refers to a specific structure made by the bird itself—such as the grassy cup nest of the American Robin or Eurasian Blackbird, or the elaborately woven hanging nest of the...
is not concealed but is usually adjacent to a tree trunk, log or low vegetation. A single grey slightly blotched egg is laid which weighs 60-75 g. Incubation
Avian incubation
Incubation refers to the process by which certain oviparous animals hatch their eggs, and to the development of the embryo within the egg. The most vital factor of incubation is the constant temperature required for its development over a specific period. Especially in domestic fowl, the act of...
duties are shared by the parents. Each bird will incubate the egg for 24 hours, with the changeover occurring around noon each day. During each incubation stint the parent will remain on the egg the whole time except early in the morning, when the bird will briefly move away to call to its mate and occasionally forage quickly. The incubation period lasts for 33–37 days, which is long for the size of the egg. Offspring may remain in their parents' territory for many years after fledging
Fledge
Fledge is the stage in a young bird's life when the feathers and wing muscles are sufficiently developed for flight. It also describes the act of a chick's parents raising it to a fully grown state...
, sometimes up to six years. These chicks do not help in incubating the eggs or raising the chicks, but nevertheless improve the breeding success of the parents. The older offspring do apparently help in territory defence, responding to playback of rivals and also participating in territorial fights, and it has been suggested that this should be treated as a form of cooperative breeding.
Relationship with humans
The Kagu had a variable role in the lives of the Kanak tribes of New Caledonia. To the tribes found in the vicinity of HienghèneHienghène
Hienghène is a commune in the North Province of New Caledonia, an overseas territory of France in the Pacific Ocean....
in the north of Grande Terre it plays a role in tribal traditions, with its name being given to people, its crest being used in the head-dresses of chiefs, and its calls being incorporated into war dances. The calls of the Kagu were considered messages to be interpreted by the chiefs. Kanaks in the vicinity of Houaïlou
Houaïlou
Houaïlou is a commune in the North Province of New Caledonia, an overseas territory of France in the Pacific Ocean....
referred to the species as the "ghost of the forest".
The species was not discovered by European scientists until the French colonisation of New Caledonia in 1852 and was not described until a specimen was brought to the Colonial Exhibition
Colonial exhibition
A colonial exhibition was a type of international exhibition intended to boost trade and bolster popular support for the various colonial empires during the New Imperialism period, which started in the 1880s with the scramble for Africa....
in Paris in 1860. This led to a surge in scientific interest in the species, which resulted in many birds being trapped for museums and zoos. The species was also trapped for food, and was considered a delicacy by European colonisers. It was also fashionable to own Kagus as pets. A campaign was run between 1977-1982 to phase out the pet trade. Today Kagus are considered very important in New Caledonia; they are a high profile endemic
Endemic (ecology)
Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...
emblem for the Territory. Its distinctive song used to be played to the nation every night as the island's TV station signed off the air. Its survival is considered important for the nation's economy and image.
Threats and conservation
Concern was first raised about the future of the Kagu in 1904. It is threatened by the introduced catsFeral cat
A feral cat is a descendant of a domesticated cat that has returned to the wild. It is distinguished from a stray cat, which is a pet cat that has been lost or abandoned, while feral cats are born in the wild; the offspring of a stray cat can be considered feral if born in the wild.In many parts of...
, pig
Pig
A pig is any of the animals in the genus Sus, within the Suidae family of even-toed ungulates. Pigs include the domestic pig, its ancestor the wild boar, and several other wild relatives...
s and dog
Dog
The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...
s. The bird was hunted for its prized crest feathers for use in hats in the 19th century. The species was also trapped extensively for museums and zoos prior to being afforded protection. New Caledonia lacked mammals prior to the arrival of humans (except for bats), and many insular species have been negatively impacted by introduced mammals. Rats have a big impact on nestlings, accounting for 55% of nestling losses. The first concrete evidence for the effect of dogs came when a New Zealand researcher's study population was quickly exterminated by dogs in the 1990s, although suspicions about the importance of dogs and other predators had been voiced prior to this and dog control measures had been enacted in some areas in the 1980s. Its initial decline was caused by subsistence hunting
Hunting
Hunting is the practice of pursuing any living thing, usually wildlife, for food, recreation, or trade. In present-day use, the term refers to lawful hunting, as distinguished from poaching, which is the killing, trapping or capture of the hunted species contrary to applicable law...
, and by capture as pet
Pet
A pet is a household animal kept for companionship and a person's enjoyment, as opposed to wild animals or to livestock, laboratory animals, working animals or sport animals, which are kept for economic or productive reasons. The most popular pets are noted for their loyal or playful...
s. They also suffer from habitat loss, caused by mining
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
and forestry
Forestry
Forestry is the interdisciplinary profession embracing the science, art, and craft of creating, managing, using, and conserving forests and associated resources in a sustainable manner to meet desired goals, needs, and values for human benefit. Forestry is practiced in plantations and natural stands...
. The Kagu is listed as endangered (CITES I), and enjoys full protection in New Caledonia. It has been the subject of highly dedicated conservation
Conservation movement
The conservation movement, also known as nature conservation, is a political, environmental and a social movement that seeks to protect natural resources including animal, fungus and plant species as well as their habitat for the future....
efforts, and is receptive to ex-situ conservation
Ex-situ conservation
Ex-situ conservation means literally, "off-site conservation". It is the process of protecting an endangered species of plant or animal outside of its natural habitat; for example, by removing part of the population from a threatened habitat and placing it in a new location, which may be a wild...
, breeding well in Nouméa Zoo. It is also prospering in Rivière Bleue Territorial Park, which has a pest
Pest (animal)
A pest is an animal which is detrimental to humans or human concerns. It is a loosely defined term, often overlapping with the related terms vermin, weeds, parasites and pathogens...
management programme and has been the site of releases into the wild of the captive bred birds.
External links
- BirdLife Species Factsheet.
- ARKive - images and movies of the kagu (Rhynochetos jubatus)
- Kagu videos, photos & sounds on the Internet Bird Collection
- Kagu information, photos & sounds at San Diego Zoo Animal Bytes.