Kagu
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| Rhynochetos jubatus Verreaux & DesMurs, 1860 |
The Kagu (French: Cagou), Rhynochetos jubatus, is a long-legged blue-greyish bird endemic to the dense mountain forests of New Caledonia. It is the only surviving member of the family Rhynochetidae, although a second, larger species of the genus Rhynochetos, the Lowland Kagu Rhynochetos orarius, has been described from Holocene subfossil remains. It is almost flightless, and builds a ground nest of sticks, laying a single egg. It has proved vulnerable to introduced rats and cats, and is threatened with extinction. The remote habitat and rarity of this species mean that little is known of its habits.
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[edit] Description
The Kagu is a ground living bird about the size of a chicken found in the forests and shrubland of New Caledonia. Its plumage is unusually bright for a bird of the forest floor; ash-grey and white coloured. It possesses powder downs which help keep it dry and insulate it in New Caledonia's tropical climate. It uses its crest to display to other members of the species. 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. It possesses bright red legs and a similarly coloured bill, and 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. Kagus make a range of different sounds, most commonly duetting in the morning, each duet lasting about 15 minutes. It possesses 'nasal corns', structures covering its nostrils, which are a feature not shared by any other bird. Also, it has only one-third the red blood cells and three times the hemoglobin per RBC compared to the usual situation in birds.(Hunt 1996)
Kagus are monogamous breeders, with pairs holding exclusive territories of around 10-28 ha (Salas & Letocart 1997). The pairs are aided in raising chicks by older offspring weho may remain in their parents territory for many years after fledging.
[edit] Threats and Conservation
The Kagu is listed as endangered (CITES I), and enjoys full protection in New Caledonia. It is threatened by the introduced cats, pigs and dogs. Its initial decline was caused by hunting for the pot, and by keeping as pets. They also suffer from habitat loss, caused by mining and forestry. The Kagu has been the subject of highly dedicated conservation efforts, and is receptive to ex-situ conservation, breeding well in Nouméa Zoo. It is also doing well in Parc Territorial de la Rivière Bleue, which has a pest management programme and has been the site of releases into the wild of the captive bred birds. Kagus are considered very important in New Caledonia, it is 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.
[edit] Classification
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[citation needed] as well as DNA-DNA hybridization data (Sibley & Ahlquist 1990). 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 adzebills Aptornithidae from New Zealand and the Sunbittern from South America. Recent studies do indicate that the Sunbittern is the closest living relative of the Kagu. For example, Fain & Houde (2004) found these to be certainly sister taxa. They and the mesites 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. But the internal structure of this group was not well resolvable by their data, and contains numerous groupings which are almost certainly bogus (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 Gondwanan 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 Sunbitterna and the mesites possess powder down too, whereas the "core Gruiformes" do not.
[edit] Multimedia
- Courting Kagu and Kagu chicks can be seen in NHNZ's documentary Islands:Splendid Isolation, some sequences are shown on the ARKive website (see "External links" below).
[edit] References
- ^ BirdLife International (2004). Rhynochetos jubatus. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 11 May 2006. Database entry includes a brief justification of why this species is endangered and the criteria used
- Cook, Simon (1998) The Kagu Birding World 11(11):440-441
- Fain, Matthew G. & Houde, Peter (2004): Parallel radiations in the primary clades of birds. Evolution 58(11): 2558-2573. doi:10.1554/04-235 PDF fulltext
- Hunt, Gavin R. (1996): Family Rhynochetidae (Kagu). In: del Hoyo, Josep; Elliott, Andrew & Sargatal, Jordi (editors): Handbook of Birds of the World, Volume 3 (Hoatzin to Auks): 218-225, plate 20. Lynx Edicions, Barcelona. ISBN 84-87334-20-2
- Salas, Michel & Letocart, Yves (1997): "Spatial Organisation and Breeding of Kagu Rhynochetos jubatus in Rivière Bleue Park, New Caledonia" Emu 97(2): 97 - 107
- Sibley, Charles Gald & Ahlquist, Jon Edward (1990): Phylogeny and classification of birds. Yale University Press, New Haven, Conn.
[edit] External links
- BirdLife Species Factsheet.
- ARKive - images and movies of the kagu (Rhynochetos jubatus)
- Kagu videos on the Internet Bird Collection
