|Scientific Name:||Dendrocygna bicolor|
|Species Authority:||(Vieillot, 1816)|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Reviewer/s:||Butchart, S. & Symes, A.|
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Native:Angola (Angola); Antigua and Barbuda; Argentina; Aruba; Bahamas; Bangladesh; Barbados; Belize; Benin; Bolivia, Plurinational States of; Bonaire, Sint Eustatius and Saba; Botswana; Brazil; Burkina Faso; Burundi; Cameroon; Canada; Cayman Islands; Central African Republic; Chad; Chile; Colombia; Congo; Congo, The Democratic Republic of the; Costa Rica; Côte d'Ivoire; Cuba; Curaçao; Dominica; Dominican Republic; Ecuador; El Salvador; Eritrea; Ethiopia; French Guiana; Gabon; Gambia; Ghana; Guadeloupe; Guatemala; Guinea; Guinea-Bissau; Guyana; Haiti; Honduras; India; Kenya; Lesotho; Madagascar; Malawi; Mali; Martinique; Mauritania; Mexico; Montserrat; Mozambique; Myanmar; Namibia; Nepal; Niger; Nigeria; Pakistan; Panama; Paraguay; Peru; Puerto Rico; Rwanda; Saint Kitts and Nevis; Saint Lucia; Saint Vincent and the Grenadines; Senegal; Sint Maarten (Dutch part); South Africa; South Sudan; Sudan; Suriname; Swaziland; Tanzania, United Republic of; Togo; Trinidad and Tobago; Turks and Caicos Islands; Uganda; United States (Hawaiian Is.); United States (Hawaiian Is.); Uruguay; Venezuela; Zambia; Zimbabwe
Vagrant:Bermuda; Bhutan; France; Grenada; Israel; Jamaica; Morocco; Oman; Portugal; Sierra Leone; Somalia; Spain; Sri Lanka; Virgin Islands, British; Virgin Islands, U.S.; Yemen
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The population is estimated to number 1,300,000-1,500,000 individuals.|
|Habitat and Ecology:||Behaviour This species makes irregular local movements within Africa, the periodic appearance of huge numbers in some areas suggesting that it is highly mobile and apt to undertake long-distance movements in search of suitable habitat (Scott and Rose 1996). Populations in Madagascar appear to be sedentary, but it is known to be locally migratory in East and West Africa, distributions in these areas varying highly between years according to the water regime (in Cameroon the presence of the species is related to flooding) (Scott and Rose 1996). The timing of the breeding season is largely determined by water availability (del Hoyo et al. 1992): populations north of the Zambezi River breed during months of low rainfall, while those in the south breed in the wet season (Scott and Rose 1996). This species breeds in single pairs or loose groups and remains in dispersed pairs or small groups whilst undergoing the post-breeding moult (Johnsgard 1978, Brown et al. 1982). During the non-breeding season congregations of 20-30, several hundreds or even thousands may occur in feeding areas (del Hoyo et al. 1992, Hockey et al. 2005). The species is active both diurnally and nocturnally (Johnsgard 1978, Brown et al. 1982), foraging mainly during the first two hours after dawn and last two hours before sunset (Hockey et al. 2005). Habitat This species inhabits shallow freshwater or brackish wetlands with tall grass (Johnsgard 1978, Brown et al. 1982). Such habitats include freshwater lakes, seasonal freshwater pools, slow-flowing streams, marshy areas, swamps in open flat terrain and flooded grasslands (Johnsgard 1978, Brown et al. 1982, Kear 2005a). It also very frequently occurs in areas of wet rice cultivation (Johnsgard 1978, Brown et al. 1982, Kear 2005a), and seeks the cover of densely vegetated wetlands while it is vulnerable and flightless during its moulting period (Kear 2005a). Diet The species is predominantly vegetarian, feeding on aquatic seeds and fruits, bulbs, leaf shoots, buds and the structural parts of aquatic plants such as grasses and rushes, although it does occasionally take small aquatic insects (Johnsgard 1978, Brown et al. 1982, Hockey et al. 2005). It is also shows a preference for cultivated rice grains (Hohman et al. 1996). Breeding site The nests of this species are predominantly mounds of plant material, often floating on water and well concealed amidst vegetation (Johnsgard 1978, Brown et al. 1982). In India however, the species is primarily tree-nesting, utilising hollow trees and even disused stick nests of large birds such as kites or crows (Madge and Burn 1988).|
|Major Threat(s):||This species is persecuted through hunting in many rice growing areas (Johnsgard 1978, Brown et al. 1982) and there has been a marked decline in numbers due to shooting anf trapping at Lake Alaotra in Madagascar (del Hoyo et al. 1992, Scott and Rose 1996). The species is also often exposed to pesticides used on rice crops, is suceptible to lead poisoning, and suffers mortality through collision with powerlines (Johnsgard 1978, Brown et al. 1982). The damming of the Senegal river has markedly decreased the habitat quality in that area, which may be having a negative impact on the population in that area (Triplett and Yesou 2000). Wetland habitat degradation on the east coast of India due to siltation, proliferation of invasive freshwater plant species (such as water hyacinth Eichornia crassipes), increased aquaculture activities and eutrophication may threaten the small proportion of the species that utilises the area (Nayak 2006). The species is also susceptible to avian botulism, so may be threatened by future outbreaks of the disease (van Heerden 1974). Utilisation The species is hunted for local consumption and trade from Lake Chilwa, Malawi (Bhima 2006). It is also hunted and traded at traditional medicine markets in Nigeria (Nikolaus 2001).|
Bhima, R. 2006. Subsistence use of waterbirds at Lake Chilwa, Malawi. In: Boere, G.; Galbraith, C., Stroud, D. (ed.), Waterbirds around the world, pp. 255-256. The Stationary Office, Edinburgh, UK.
Brown, L. H.; Urban, E. K.; Newman, K. 1982. The birds of Africa vol I. Academic Press, London.
Delany, S.; Scott, D. 2006. Waterbird population estimates. Wetlands International, Wageningen, The Netherlands.
del Hoyo, J.; Elliot, A.; Sargatal, J. 1992. Handbook of the Birds of the World, vol. 1: Ostrich to Ducks. Lynx Edicions, Barcelona, Spain.
Hockey, P. A. R.; Dean, W. R. J.; Ryan, P. G. 2005. Roberts birds of southern Africa. Trustees of the John Voelcker Bird Book Fund, Cape Town, South Africa.
Hohman, W. L.; Stark T. M.; Moore J. L. 1996. Food availability and feeding preferences of breeding fulvous whistling-ducks in Louisiana ricefields. Wilson Bulletin 108(1): 137-150.
IUCN. 2012. IUCN Red List of Threatened Species (ver. 2012.1). Available at: http://www.iucnredlist.org. (Accessed: 19 June 2012).
Johnsgard, P. A. 1978. Ducks, geese and swans of the World. University of Nebraska Press, Lincoln and London.
Kear, J. 2005. Ducks, geese and swans volume 1: general chapters; species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, U.K.
Madge, S.; Burn, H. 1988. Wildfowl. Christopher Helm, London.
Nayak, A . K. 2006. Status of migratory shorebirds at Bhitarkanika and Chilika wetlands on the est coast of India. In: Boere, G.; Galbraith, C., Stroud, D. (ed.), Waterbirds around the world, pp. 305-307. The Stationary Office, Edinburgh, UK.
Nikolaus, G. 2001. Bird exploitation for traditional medicine in Nigeria. Malimbus 23: 45-55.
Scott, D. A.; Rose, P. M. 1996. Atlas of Anatidae populations in Africa and western Eurasia. Wetlands International, Wageningen, Netherlands.
Triplett, P.; Yesou, P. 2000. Controlling the flood in the Senegal Delta: do waterfowl populations adapt to their new environment? Ostrich 71((1-2): 106-111.
van Heerden, J. 1974. Botulism in the Orange Free State goldfields. Ostrich 45(3): 182-184.
|Citation:||BirdLife International 2012. Dendrocygna bicolor. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 20 June 2013.|
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