Corvus Classification Essay

The house crow (Corvus splendens), also known as the Indian, greynecked, Ceylon or Colombo crow,[2] 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. It is between the jackdaw and the carrion crow in size (40 cm (16 in) in length) but is slimmer than either. The forehead, crown, throat and upper breast are a richly glossed black, whilst the neck and breast are a lighter grey-brown in colour. The wings, tail and legs are black. There are regional variations in the thickness of the bill and the depth of colour in areas of the plumage.

Taxonomy[edit]

The nominate race C. s. splendens is found in Pakistan, India, Nepal and Bangladesh and has a grey neck collar. The subspecies C. s. zugmayeri is found in the dry parts of South Asia and Iran and has a very pale neck collar. The subspecies C. s. protegatus is found in southern India, the Maldives (sometimes separated as maledivicus) and Sri Lanka and is darker grey. C. s. insolens, found in Myanmar, is the darkest form and lacks the grey collar.[3]

Distribution and habitat[edit]

It has a widespread distribution in southern Asia, being native to Nepal, Bangladesh, India, Pakistan, Sri Lanka, Maldives and Laccadive Islands, South West Thailand and coastal southern Iran. It was introduced to East Africa around Zanzibar (about 1897)[4] and Port Sudan. It arrived in Australia via ship but has up to now been exterminated. Recently, it has made its arrival in Europe and has been breeding in the Dutch harbour town Hook of Holland since 1998.

A population between 200 and 400 birds has been present in Sham Shui Po, New Kowloon, Hong Kong, in particular Lai Kok Estate and Sham Shui Po Park, as well as Kowloon Tsai Park in Kowloon Tsai.[5] An individual has been present in Cork Harbour on the south coast of Ireland since early September 2010.[6]

In the New World, a small population of house crows is established in the area around St. Petersburg, Florida.[7]

It is associated with human settlements throughout its range, from small villages to large cities. In Singapore, there was a density of 190 birds/km2 in 2001 with efforts to suppress the population in planning.[8][9]

Due to a human population explosion in the areas it inhabits, this species has also proportionately multiplied. Being an omnivorous scavenger has enabled it to thrive in such circumstances.

The invasive potential for the species is great all over the tropics. This species is able to make use of resources with great flexibility and appears to be associated with humans, and no populations are known to exist independently of humans.[10]

Behaviour[edit]

Diet[edit]

House crows feed largely on refuse around human habitations, small reptiles and mammals,[11] and other animals such as insects and other small invertebrates, eggs, nestlings, grain and fruits. House crows have also been observed swooping down from the air and snatching baby squirrels. Most food is taken from the ground, but also from trees as opportunity arises. They are highly opportunistic birds and given their omnivorous diet, they can survive on nearly anything that is edible. These birds can be seen near marketplaces and garbage dumps, foraging for scraps. They have also been observed to eat sand after feeding on carcasses.[12]

Nesting[edit]

At least some trees in the local environment seem to be necessary for successful breeding although house crows occasionally nest on telephone towers.[13] It lays 3–5 eggs in a typical stick nest, and occasionally there are several nests in the same tree. In South Asia they are parasitized by the Asian koel. Peak breeding in India as well as Peninsular Malaysia is from April to July. Large trees with big crowns are preferred for nesting.[14]

Roosting[edit]

House crows roost communally near human habitations and often over busy streets. A study in Singapore found that the preferred roost sites were in well-lit areas with a lot of human activity, close to food sources and in tall trees with dense crowns that were separated from other trees. The roost sites were often enclosed by tall buildings.[15] Before flying into roost trees, crows make pre-roosting aggregations perched on TV antennas, roof tops, wayside trees, open fields, and feed or preen during this time.[16]

Voice[edit]

The voice is a harsh kaaw-kaaw.[3]

Relationship to humans[edit]

It is suspected that paramyxoviruses, such as PMV 1 that causes of Newcastle disease[17] may be spread by Corvus splendens. Outbreaks of Newcastle disease in India were often preceded by mortality in crows.[18] They have also been found to carry Cryptococcus neoformans, which can cause cryptococcosis in humans.[19]

House crows in Tanzania curiously showed an absence of blood parasites, although some species such as Trypanosoma corvi have been first described from this species.[20] Pathologist T.R. Lewis expressed surprise at the numbers of haematozoa present in the blood of house crows from Calcutta.[21]

Regional names[edit]

Assamese - পাতি কাউৰী, Bengali - পাতিকাক, Gujarati - દેશી કાગડો, Hindi - कौवा, Kannada - ಕಾಗೆ, Malayalam - പേനക്കാക്ക, Marathi - कावळा, Nepali - घर काग, Punjabi - ਕਾਂ, Sanskrit - ग्राम काक, वायस, Tamil - வீட்டுக் காகம், Telugu - కాకి.[22] Laturi- काळा कावळा Bamni-गणू कावळा

Gallery[edit]

  • Grooming behaviour in India.

  • Grooming after bath in the rain in India.

  • In flight in Kolkata, West Bengal, India.

  • Assembling in the evening

  • House crow feeding chicks in Chennai, India

References[edit]

  1. ^BirdLife International (2012). "Corvus splendens". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013. 
  2. ^"House crow: animal pest alert". agric.wa.gov. Government of Western Australia: Department of Agriculture and Food. Retrieved 30 October 2015. 
  3. ^ abRasmussen, PC & JC Anderton (2005) Birds of South Asia: The Ripley Guide. Smithsonian Institution and Lynx Edicions. Vol 2. p.598
  4. ^Cooper, John E. (1996). "Health studies on the Indian house crow (Corvus splendens)". Avian Pathology. 25 (2): 381–386. doi:10.1080/03079459608419148. 
  5. ^[1][2][3][4]
  6. ^Ryall, C. 2016. Further records and updates of range extension in House Crow Corvus splendens. Bulletin of the British Ornithologists' Club 136(1):39-45
  7. ^Pranty, W. 2004. Florida’s exotic avifauna: a preliminary checklist. - Birding, August 2004: 362:372.
  8. ^Brook, B.W., Sodhi, N.S., Soh, M.C.K., Lim, H.C. (2003) Abundance and projected control of invasive house crows in Singapore. Journal of Wildlife Management 67(4):808-817
  9. ^Ryall, C., 2002. Further records of range extension in the House Crow Corvus splendens. BOC Bulletin 122(3): 231-240
  10. ^Nyari, A., Ryall, C. and Peterson, A. T. 2006. Global invasive potential of the house crow Corvus splendens based on ecological niche modeling. J. Avian Biol. 37:306-311.
  11. ^Mikula, P.; Morelli, F.; Lučan, R. K.; Jones, D. N.; Tryjanowski, P. (2016). "Bats as prey of diurnal birds: a global perspective". Mammal Review. doi:10.1111/mam.12060. 
  12. ^Amey Jayesh Kambli (2004). "Geophagy by three species of crows near carcass dumping ground at Jodhpur, Rajasthan". Newsletter for Ornithologists. 1 (5): 71. 
  13. ^Lamba, B.S. 1963. The nidification of some common Indian birds. Part I. J. Bombay Nat. Hisl. Soc. 60:121-133
  14. ^Soh MCK, NS Sodhi, RKH Seoh, BW Brook (2002) Nest site selection of the house crow (Corvus splendens), an urban invasive bird species in Singapore and implications for its management. Landscape and Urban planning 59:217-226
  15. ^Kelvin S.-H. Peh and Navjot S. Sodhi (2002) Characteristics of Nocturnal Roosts of House Crows in Singapore. The Journal of Wildlife Management 66(4):1128-1133
  16. ^Peh, Kevin S-H (2002). "Roosting behaviour of house crow (Corvus splendens) in relation to environmental variables"(PDF). The Raffles Bulletin of Zoology. 50: 257–262. 
  17. ^Roy, P., Venugopalan, A.T., Manvell, R. 1998 Isolation of Newcastle disease virus from an Indian house crow. Tropical animal health and production 30 (3):177-178
  18. ^Blount, W.P. (1949). Diseases of Poultry. (London, Balliere, Tindall and Cox).
  19. ^S. Gokulshankar, S. Ranganathan, M. S. Ranjith and A. J. A. Ranjithsingh (2004) Prevalence, serotypes and mating patterns of Cryptococcus neoformans in the pellets of different avifauna in Madras, India. Mycoses, 47:310–314
  20. ^Dirie, M.F., Ashford, R.W., Mungomba, L.M., Molyneux, D.H. & Green, E.E. (1990). Avian trypanosomes in Simulium and sparrowhawks (Accipiter nisus). Parasitology, 101,243-247.
  21. ^Lewis, Timothy Richards (1879). The microscopic organisms found in the blood of man and animals, and their relation to disease. Calcutta: Government Press. p. 71. 
  22. ^http://birds.thenatureweb.net/housecrow.aspx

External links[edit]

Parents feeding nestlings

Crow, (genus Corvus), any of various glossy black birds found in most parts of the world, with the exception of southern South America. Crows are generally smaller and not as thick-billed as ravens, which belong to the same genus. A large majority of the 40 or so Corvus species are known as crows, and the name has been applied to other, unrelated birds. Large crows measure about 0.5 metre (20 inches) long, with wingspans that can reach 1 metre (39 inches).

Crows feed chiefly on the ground, where they walk about purposefully. They are omnivores that enjoy meat and may even attack and kill young, weak animals. This habit makes them unpopular with farmers, as does the bird’spropensity to raid grain crops. Berries, insects, the eggs of other birds, and carrion are also eaten. Crows will make off with shreds of roadkill and store tidbits in trees, caching the meat like a leopard does for later consumption. Sometimes they bury seeds or store them in crevices in bark. They occasionally steal food from other animals, sometimes cooperating with other crows to raid food from otters, vultures, and water birds.

Crows live in large, close-knit families, and, like social mammals, they not only hunt and forage together but also defend territories and care for the young together. Most species, however, do not nest in colonies. Each mating pair has its own nest of sticks and twigs, usually high up in a tree. There are laid five or six greenish-to-olive eggs, with darker speckles. Young crows may spend up to six years with their parents before breeding on their own. As winter approaches, northern crows gather into large night-roosting groups. These flocks can include tens of thousands of birds and occasionally hundreds of thousands. Possible reasons for this seasonal gregariousness are warmth, protection against predators such as owls, or information exchange. A crow may live 13 years in the wild and more than 20 years in captivity.

Highly intelligent, crows can be masterful mimics. They have been trained to count aloud up to seven, and some crows have learned more than 100 words and up to 50 complete sentences; others have been known to mimic their owners’ voices in order to call dogs and taunt horses. They also exhibit great curiosity, fueling a reputation as inventive pranksters and calculating thieves. They fly off with people’s mail, pull clothespins off lines, and make off with unattended objects such as car keys. Two species—the New Caledonian crow (C. moneduloides) and the ‘alalā, or Hawaiian crow (C. hawaiiensis)—use stick-type foraging tools to obtain food from small holes and crevices. Such sophisticated tool use is only practiced by a handful of animal species.

Some common crows are the American crow (C. brachyrhynchos) of North America and the carrion crow (C. corone) of Europe and most of Asia. A subspecies of the carrion crow with gray on the back of the neck and breast is called the hooded crow (C. corone cornix). Sometimes considered a separate species, it is found between western Europe and eastern Asia and in the northern British Isles. Other crows include the house crow (C. splendens) of the Indian subcontinent (introduced in eastern Africa); the pied crow (C. albus), with white nape and breast, of tropical Africa; and the fish crow (C. ossifragus) of southeastern and central North America. Other members of the genus Corvus not called crows are the raven, jackdaw, and rook.

For birds in other families that are sometimes called crows, seecurrawong, or piping-crow; drongo, or king crow; kokako, or wattled crow; and rockfowl, or bald crow.

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