Grouse are a group of birds from the order Galliformes. Grouse inhabit temperate and subarctic regions of the northern hemisphere. They are game and are sometimes hunted for food.
In all but one species (the Willow Grouse), males are polygamous, and many species have elaborate courtship displays. These heavily built birds have legs feathered to the toes. Most species are year-round residents, and do not migrate.
These birds feed mainly on vegetables, but will also feed on insects, especially when feeding young.
The American Ornithologists' Union includes grouse (Tetraonidae) as a subfamily of Phasianidae. Based on mtDNA sequences, some systematists believe that certain species belong in new genera
Showing posts with label 3. Show all posts
Showing posts with label 3. Show all posts
Grouse
emu
Emu or Dromaius novaehollandiae, is the largest bird native to Australia and the only extant member of the genus Dromaius. It is also the second-largest extant bird in the world by height, after its ratite relative, the ostrich. The soft-feathered, brown, flightless birds reach up to 2 m (6 ft) in height. The Emu is common over most of mainland Australia, although it avoids heavily populated areas, dense forest and arid areas. Emus can travel great distances at a fast, economical trot and, if necessary, can sprint at 50 km/h (30 mph) for some distance at a time.[3] They are opportunistically nomadic and may travel long distances to find food; they feed on a variety of plants and insects.
Conservation status
Emus were used as a source of food by indigenous Australians and early European settlers. Aborigines used a variety of techniques to catch the bird, including spearing them while they drank at waterholes, poisoning waterholes, catching Emus in nets, and attracting Emus by imitating their calls or with a ball of feathers and rags dangled from a tree.[17] Europeans killed Emus to provide food and to remove them if they interfered with farming or invaded settlements in search of water during drought. An extreme example of this was the Emu War in Western Australia in 1932, when Emus that flocked to Campion during a hot summer scared the town’s inhabitants and an unsuccessful attempt to drive them off was mounted. In John Gould's Handbook to the Birds of Australia, first published in 1865, he laments the loss of the Emu from Tasmania, where it had become rare and has since become extinct; he notes that Emus were no longer common in the vicinity of Sydney and proposes that the species be given protected status.[4] Wild Emus are formally protected in Australia under the Environment Protection and Biodiversity Conservation Act 1999.
Although the population of Emus on mainland Australia is thought to be higher now than before European settlement,[5] some wild populations are at risk of local extinction due to small population size. Threats to small populations include the clearance and fragmentation of areas of habitat; deliberate slaughter; collisions with vehicles; and predation of the young and eggs by foxes, feral and domestic dogs, and feral pigs. The isolated Emu population of the New South Wales North Coast Bioregion and Port Stephens is listed as endangered by the New South Wales Government.[21]
The Emu subspecies that previously inhabited Tasmania became extinct following the European settlement of Australia in 1788; the distribution of the mainland subspecies has also been affected by human activities. Once common on the east coast, Emu are now uncommon; by contrast, the development of agriculture and the provision of water for stock in the interior of the continent have increased the range of the Emu in arid regions. Emus are farmed for their meat, oil and leather.
DODO (Raphus cucullatus)
The Dodo (Raphus cucullatus) was a flightless bird that lived on the island of Mauritius. Related to pigeons and doves, it stood about a meter tall (three feet), lived on fruit and nested on the ground.
The dodo has been extinct since the mid-to-late 17th century. It is commonly used as the archetype of an extinct species because its extinction occurred during recorded human history, and was directly attributable to human activity. The adjective phrase "as dead as a dodo" means undoubtedly and unquestionably dead. The verb phrase "to go the way of the dodo" means to become extinct or obsolete, to fall out of common usage or practice, or to become a thing of the past.
Biology
Systematics and evolution
The dodo is a close relative of modern pigeons and doves. mtDNA cytochrome b and 12S rRNA sequences[4] analysis suggests that the dodo's ancestors diverged from those of its closest known relative, the Rodrigues Solitaire (which is also extinct), around the Paleogene-Neogene boundary.[5] As the Mascarenes are of volcanic origin and less than 10 million years old, both birds' ancestors remained most likely capable of flight for considerable time after their lineages' separation. The same study has been interpreted[6] to show that the Southeast Asian Nicobar Pigeon is the closest living relative of the dodo and the Reunion Solitaire.
However, the proposed phylogeny is rather questionable as regards the relationships of other taxa[7] and must therefore be considered hypothetical pending further research; considering biogeographical data, it is very likely to be erroneous. All that can be presently said with any certainty is that the ancestors of the didine birds were pigeons from Southeast Asia or the Wallacea, which agrees with the origin of most of the Mascarenes' birds. Whether the dodo and Rodrigues Solitaire were actually closest to the Nicobar Pigeon among the living birds, or whether they are closer to other groups of the same radiation such as Ducula, Treron or Goura pigeons is not clear at the moment.
For a long time, the dodo and the Rodrigues Solitaire (collectively termed "didines") were placed in a family of their own, the Raphidae. This was because their relationships to other groups of birds (such as rails) had yet to be resolved. As of recently, it appears more warranted to include the didines as a subfamily Raphinae in the Columbidae.
The supposed "White Dodo" is now thought to be based on misinterpreted reports of the Réunion Sacred Ibis and paintings of apparently albinistic dodos; a higher frequency of albinos is known to occur occasionally in island species (see also Lord Howe Swamphen).
Morphology and flightlessness
In October 2005, part of the Mare aux Songes, the most important site of dodo remains, was excavated by an international team of researchers. Many remains were found, including bones from birds of various stages of maturity,[8] and several bones obviously belonging to the skeleton of one individual bird and preserved in natural position.[2] These findings were made public in December 2005 in the Naturalis in Leiden. Before this, few associated dodo specimens were known, most of the material consisting of isolated and scattered bones. Dublin's Natural History Museum and the Oxford University Museum of Natural History, among others, have a specimen assembled from these disassociated remains. A Dodo egg is on display at the East London museum in South Africa. Until recently, the most intact remains, currently on display at the Oxford University Museum of Natural History, were one individual's partly skeletal foot and head which contain the only known soft tissue remains of the species.
This 1651 dodo image by Jan Savery is based on a 1626 painting by Roelant Savery, made from a stuffed specimen - note that it has two left feet and that the bird is obese from captivity.
This 1651 dodo image by Jan Savery is based on a 1626 painting by Roelant Savery, made from a stuffed specimen - note that it has two left feet and that the bird is obese from captivity.
The remains of the last known stuffed dodo had been kept in Oxford's Ashmolean Museum, but in the mid-18th century, the specimen - save the pieces remaining now - had entirely decayed and was ordered to be discarded by the museum's curator or director in or around 1755. According to the current curator, Malgosia Nowak-Kemp, the commonly-cited story that the remains were merely damaged - implying that more material could or should have been salvaged, and/or that the present remains were serendipitiously saved against the curator's orders - is an urban legend arising from a mistranslation of the Latin museum records.
In June 2007, adventurers exploring a cave in the Indian Ocean discovered the most complete and well-preserved dodo skeleton ever.[9]
From artists' renditions we know that the Dodo had greyish plumage, a 23-centimetre (9-inch) bill with a hooked point, very small wings, stout yellow legs, and a tuft of curly feathers high on its rear end. Dodos were very large birds, weighing about 23 kg (50 pounds). The sternum was insufficient to support flight; these ground-bound birds evolved to take advantage of an island ecosystem with no predators.
The traditional image of the dodo is of a fat, clumsy bird, but this view has been challenged in recent times. The general opinion of scientists today is that the old drawings showed overfed captive specimens.[10] As Mauritius has marked dry and wet seasons, the dodo probably fattened itself on ripe fruits at the end of the wet season to live through the dry season where food was scarce; contemporary reports speak of the birds' "greedy" appetite. Thus, in captivity, with food readily available, the birds would become overfed very easily.
Diet
The tambalacoque, also known as the "dodo tree", was hypothesized by Stanley Temple to have been eaten from by Dodos, and only by passing through the digestive tract of the dodo could the seeds germinate; he claimed that the tambalacocque was now nearly extinct due to the dodo's disappearance. He force-fed seventeen tambalacoque fruits to wild turkeys and three germinated. Temple did not try to germinate any seeds from control fruits not fed to turkeys so the effect of feeding fruits to turkeys was unclear. Temple also overlooked reports on tambalacoque seed germination by A. W. Hill in 1941 and H. C. King in 1946, who found the seeds germinated, albeit very rarely, without abrading.[11][12][13][14]
Extinction
Landscape with birds - dodo painted by Roelant Savery (1628).
Landscape with birds - dodo painted by Roelant Savery (1628).
Reunion or white dodo painted by Pieter Withoos (1654-1693).
Reunion or white dodo painted by Pieter Withoos (1654-1693).
As with many animals evolving in isolation from significant predators, the dodo was entirely fearless of people, and this, in combination with its flightlessness, made it easy prey.[15] But journals are full of reports regarding the bad taste and tough meat of the dodo, while other local species such as the Red Rail were praised for their taste. It is commonly believed that the Malay sailors held the bird in high regard and killed them only to make head dressings used in religious ceremonies.[16] However, when humans first arrived on Mauritius, they also brought with them other animals that had not existed on the island before, including dogs, pigs, cats, rats, and Crab-eating Macaques, which plundered the dodo nests, while humans destroyed the forests where the birds made their homes;[17] currently, the impact these animals — especially the pigs and macaques — had on the dodo population is considered to have been more severe than that of hunting. The 2005 expedition's finds are apparently of animals killed by a flash flood; such mass mortalities would have further jeopardized an already extinction-prone species.[18]
Although there are scattered reports of mass killings of dodos for provisioning of ships, archaeological investigations have hitherto found scant evidence of human predation on these birds. Some bones of at least two dodos were found in caves at Baie du Cap which were used as shelters by fugitive slaves and convicts in the 17th century, but due to their isolation in high, broken terrain were not easily accessible to dodos naturally.[19] By 1755, Cossigny reports that the number of refugees and settlers which cut down the inland forest was so high that the well-flighted Mauritius Blue Pigeon was rapidly declining all over the island.[citation needed]
There is some controversy surrounding the extinction date of the dodo. Roberts & Solow state that "the extinction of the Dodo is commonly dated to the last confirmed sighting in 1662, reported by shipwrecked mariner Volkert Evertsz" (Evertszoon), but many other sources suggest the more conjectural date 1681. Roberts & Solow point out that because the sighting prior to 1662 was in 1638, the dodo was likely already very rare by the 1660s, and that thus a disputed report from 1674 cannot be dismissed off-hand.[20] Statistical analysis of the hunting records of Issac Johannes Lamotius, carried out by Julian Hume and coworkers,[citation needed] give a new estimated extinction date of 1693, with a 95% confidence interval of 1688 to 1715. Considering more circumstantial evidence such as travellers' reports and the lack of good reports after 1689,[19] it is likely that the dodo became extinct before 1700; thus, the last Dodo died barely more than a century after the species' discovery in 1581.[21]
Few took particular notice of the extinct bird. By the early 19th century it seemed altogether too strange a creature, and was believed by many to be a myth. With the discovery of the first batch of dodo bones in the Mare aux Songes and the reports written about them by George Clarke, government schoolmaster at Mahébourg, from 1865 on,[22] interest in the bird was rekindled. In the same year in which Clarke started to publish his reports, the newly-vindicated bird was featured as a character in Lewis Carroll's Alice's Adventures in Wonderland. With the popularity of the book, the dodo became a well-known and easily recognizable icon of extinction.
Subscribe to:
Posts (Atom)