Wildfowl at Risk, 1992

Wildfowl at Risk, 1992 ANDY J. GREEN Brief accounts are given of the status and causes of decline of 50 species and subspecies of wildfowl (.Anseriformes) that are known to be threatened with extinction. A number of changes are made to the earlier list presented in this journal by Kear & Williams (1978), and each taxon is assigned a provisional category of threat in line with recent proposals for the re-evaluation o f IUCN categories made by Mace & Lande (1991). This is a short review of the Anseriform to the list. Information on the status of species and subspecies (families Anatidae wildfowl has been greatly enhanced by the and Anhimidae) that are currently consid expansion of the mid-winter censuses ered “threatened” with extinction. It gives organised by IWRB and Asian Wetland summaries of the current understanding of Bureau, which now cover large parts of the status of and threats to each taxon, Europe, Asia, Africa and South America. and is based on a more detailed and con The Asian Waterfowl Census (van der Ven tinuing review of these taxa that was initi 1987, 1988, Scott & Rose 1989, Perennou et ated in 1990 on behalf of The Wildfowl & al. 1990, Perennou & Mundkur 1991) has Wetlands Trust. These activities are now produced particularly useful data on a conducted under the umbrella of the new large number of threatened taxa, and is Threatened Waterfowl Research Group of often referred to below. In the past 13 the International Waterfowl & Wetlands years, successful conservation action has Research Bureau (IWRB) which produces a brought a few taxa out of danger, while the biannual newsletter circulated to over 300 advance of wetland destruction, deforesta people across the world working on threat tion and intense hunting pressure has ened wildfowl. This follows on from earlier brought additional taxa into danger. work by Dr Janet Kear (formerly Chair of Lists of threatened wildfowl are the Endangered Waterfowl Group) and inevitably compiled partly on a subjective Gwyn Williams who published earlier basis. The IUCN categories themselves are reviews of threatened wildfowl in this jour subjective (with the exception of nal (Kear & William s 1978, Kear 1979) that EXTINCT) and are inevitably applied in dif contain much historical information that is ferent ways by different workers in differ not repeated here. The list of taxa present ent continents. This in turn means that a ed here differs considerably from the earli global list ends up with a strong regional er list of Kear & Williams (1978) for a num bias that may explain some apparent dis ber of reasons. It also differs considerably crepancies in the current IUCN list. For from the current IUCN list (WCMC 1990) example, New Zealand and Madagascar which does not contain wildfowl threat both hold a number of highly endangered ened only at the subspecific level. bird species, and by comparison the Blue As research into wildfowl taxonomy has Duck Hymenolaimus malacorhynchos and progressed and knowledge of the distribu M eller’s Duck Anas melleri may seem tion and population size of wildfowl taxa “safe”. Yet they both have declining popu has improved, it has become clear that lations of only a few thousand and deserve some taxa on the earlier list of Kear & listing before the Lesser White-fronted Williams are not significantly “threatened”, Goose Anser erythropus (currently listed as or cannot genuinely be considered to be a Rare) which is thought to have a popula separate taxon. Equally, improved moni tion of over 100,000. toring has identified additional taxa that The list presented includes an attempt to are in rapid decline and have low popula re-evaluate “threatened” status in a more tion sizes, and these taxa have been added objective manner in line with current 160 W ildfowl 43 (1992): 160-184 W ildfow l at Risk 161 moves to reevaluate IUCN categories them that of Livezey used by Madge & Burn selves. New categories proposed by Mace (1988) and includes a number of sub & Lande (1991) depend primarily on the species whose validity is in question and probability that a taxon will go extinct. The which are not listed in some taxonomies information needed to calculate this prob such as that of Sibley & Monroe (1990). ability accurately is not available, and so a number of alternative criteria are offered that depend on population size, population Status Reviews of Threatened Taxa fragmentation and current or projected rates of decline or catastrophes. In this Northern Screamer Chauna chavaría review, the current IUCN category (WCMC IUCN K/V 1990) is listed for each taxon. T he cate gories are E (ENDANGERED), V (VULNERA This species is restricted to lowland BLE), R (RARE), I (INDETERMINATE), K marshes in northern Colombia and north (INSUFFICIENTLY KNOWN) and K* (CUR western Venezuela. It is declining in some RENTLY UNDER REVIEW). These existing areas due to habitat loss from develop categories are followed by provisional new ment, but remains common in some locali Mace-Lande style categories assigned ties (Collar & Andrew 1988) such as the using the following criteria. These are a Ciénagas de Juan Manuel and adjacent modification of those offered by Mace & areas (Scott & Carbonell 1986). In Colom Lande (1991), necessary due to a lack of bia, the lower Magdalena, Sinu and Atrato quantitative data on actual or projected valleys were the major areas occupied rates of decline: (Hilty & Brown 1986). Total population probably exceeds 10,000 (N.J. Collar in litt. V = VULNERABLE. Population of 2500 to 1992). 10,000 with current or projected causes of decline OR population of 10,000 to 100,000 West-Indian Whistling Duck in rapid and widespread decline. Dendrocygna arborea IUCN R/E E = ENDANGERED. Population of 250 to This species has been recorded widely in 2500. the Caribbean from the Bahamas, Cuba, Haiti, Dominican Republic, Jamaica, Cay C = CRITICAL. Population of under 250. man Islands, Puerto Rico, Virgin Islands and Leeward Islands. It is still widespread, H = Taxon threatened by increasing but populations in Cuba, Jamaica, Domini hybridisation with an introduced species. can Republic, Haiti, Puerto Rico, Cayman Islands are all declining due to widespread These categories are assigned on the wetland destruction, logging and indis basis of the most pessimistic view within criminate and uncontrolled hunting (King the bounds of current knowledge. For 1978-79, M. Van Liefde pers, comm., N. example, if a population is estimated at Varty pers, comm., A. Sutton in litt.). 200-2000, it is assumed to be 200 and if The total population may be no more rates of decline are not known, they are than several thousand and the present assumed to be rapid. These new cate Jamaican population is likely to be under gories were originally assigned during the 1000 (N. Varty pers. com m .). It is found course of a review of the waterfowl to locally in good numbers in Cuba, a “large establish priorities for captive breeding population” is found on Barbuda and there and other programmes conducted in has been a recovery of numbers on the association with the Captive Breeding east coast of Puerto Rico (Collar & Andrew Specialist Group of IUCN (Ellis-Joseph, 1988). A population in Central Conocarpus Hewston & Green 1992). It must be Swamp, Grand Cayman was eliminated by emphasised that these proposed new cat vegetation clearance (Scott & Carbonell egories are under review, that they are 1986). Although illegal in much of the not proposed by IUCN itself and that they range, shooting remains widespread. In the do not represent a statement of how the Cayman islands there is no hunting closed categories in future official IUCN lists will season and, outside the winter, D. arborea be revised. are the only duck to shoot (M. Van Liefde The taxonomy used in this review follows pers. comm.). Taking of eggs for food has 162 Wildfowl at Risk contributed to the decline in Puerto Rico golia. In 1977, birds were breeding at Ogii and other islands ( J. Bond in litt. 1961, H. Nor and Oigon Nor in the north-central Raffaele in litt. 1973). In the Jibaro W et steppe (K itson 1978). In China, the species lands in Cuba, a large population fed in is currently breeding in Inner Mongolia rice paddies, but the numbers declined Autonomous Region, Heilongjiang Province drastically after the introduction of a pest and Jilin Province (Scott 1989). The winter control programme in 1974 (Scott & Car ing populations in Korea and Japan have bonell 1986). crashed since 1950 w here it is now an irregular visitor (K ear & Williams 1978). Recherche Cape Barren Goose Cereopsis Wintering now occurs mainly in China in novae-hollandiae griseus IUCN -/E Shandong, coastal Jiangsu, Anhui and Jianxi Provinces. The Asian Waterfowl Cen The isolated population of this goose in sus recorded 71,000 from Poyang Lake, the Recherche Islands off the south coast Jiangxi Province in 1988, and 35,000 in of Western Australia has recently been Yancheng marshes, coastal Jiangsu described as a distinct subspecies (Storr Province in January 1988 (Scott 1989). 1980). This taxon is at risk owing to its These counts may be overestimates, and small population of about 1000. The nomi the total Chinese wintering population may nate race has a population of around be less than 50,000 (Jianjian Lu in litt.). 16,000 concentrated on islands off Eyre The decline in Russia has been attributed Peninsula, South Australia, off Wilson’s to habitat destruction, hydro-electric Promontory, Victoria and the Furneaux schemes, controlling of river flows and Group, Tasmania. This population is hunting pressure (Kolosov 1983, Borodin increasing and under no threats (Marchant 1984). T he geese are relatively easy to & Higgins 1990).

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