Justification This species has a very small population which is suspected to be undergoing a continuing and rapid decline as a result of habitat loss, illegal hunting and disturbance. It is therefore listed as Endangered.

Family/Sub-family Anatidae

Species name author Gould, 1864

Taxonomic source(s) Sibley and Monroe (1990, 1993)

Identification 52-58 cm. Striking merganser with shaggy crest and scaled flanks. Adult male has black, glossed green head and neck with long crest. Creamy-white lower foreneck, breast and central underparts. Whitish flanks, ventral region, and rump with grey scaling. Blackish mantle, hindneck and scapulars. Mostly white innerwing. Adult female has warm buffish head and neck with dusky lores and wispy crest. Whitish breast and central underparts. Similar spp. Male Red-breasted Merganser M. serrator has white collar and rufous breast and lacks heavy scaling on flanks. Female also lacks scaling.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

1,000-2,499

decreasing

862,000 km²

No

Range & population Mergus squamatus breeds in Khabarovsk, Amur, the Jewish Autonomous Region and Primorye in south-east Russia, North Korea and Heilongjiang, Jilin and Inner Mongolia in north-east China. Some birds winter in south-east Russia and North Korea, but most winter in central and southern China (the majority of wintering flocks found on the lower branch of the Yangtze River⁵), with small numbers in Japan, South Korea, Taiwan (China), Myanmar and Thailand. Its population is estimated at fewer than 2,500 individuals and declining. Most breed in Russia where, in the early 1980s, there were c.1,000 pairs in Primorye and c.100 pairs in Khabarovsk but, by 1990, the total number was estimated at c.950 pairs. However, recent survey results revealed that breeding density along rivers in Primorye has more than doubled since the 1960s/1970s², and a total of 173 individuals were recorded along a 20 km stretch of the Iman River in 2003³. Where historical data was available for comparison, breeding populations in Russia showed some increases but this trend seems to have stabilised during 2003-2007⁶. The breeding population in China is estimated at 200-250 pairs (now restricted to the Chingbai mountains following extinction in the Xingan Mountains and Wusuli basin) and declining⁶. In 2003 a population of c.40 individuals was found on the lower Chongchon river in central Korea¹. 300 individuals (including one flock of 80 birds) were recorded on a stretch of river not more than 3 km long congregating post-breeding prior to migration at Song Jiang He in Jilin Province, China⁴. Surveys of c1,000 km of rivers and 11 reservoirs in south-east China in winter 2006 and 2008 found a total of 71 individuals⁷, and wintering birds at four sites in northern Jiangxi between 2002-2007 included a peak of 88 on a 22 km stretch of Xinjiang River⁹, but the whereabouts of the majority of the wintering population are still unknown⁷.

Important Bird Areas Click here to view map showing IBAs where species is recorded and triggers any of the IBA criteria.

Ecology: It breeds below c.900 m in mountainous areas, along rivers with tall riverine forest, mainly within the temperate conifer-broadleaf forest zone. It is largely confined to primary forests, with an abundance of potential nest-holes. During a study on Russian breeding grounds river size, mountain slope, human population, estimated forest cover and water clarity all failed to explain the observed distribution, but the species showed a marked preference for the middle reaches of rivers². On passage and in winter it feeds along large rivers. Flocks of up to 20 individuals have been noted on passage or in winter¹.

Threats In the 1960s and 1970s, its decline in Russia coincided with economic development of the taiga. Primary forests in the valleys of all large rivers were greatly altered, but large-scale deforestation in river valleys is now prohibited, however the new Russian Forest Codex (2007) requires a water protection zone (no deforestation) of only 100 m for large rivers (50 m on each side), and 50 m (25 m each side) for rivers shorter that 100 km, which is likely to significantly reduce suitable breeding habitat for the merganser, which nests up to 150 m from the river⁶. Logging of river sources and adjacent slopes has led to reduced spring water levels and changes in fish abundance; since logging began on the Avvakumovka River in 2004 spring water levels and merganser populations have undergone continuous declines⁶. Other major threats within the breeding range include illegal hunting, drowning in fishers' nets (a major cause of mortality at Russian breeding sites in 2003-2007⁶), disturbance from motor boats during the breeding season, river pollution and natural predators. Increased hunting of waterfowl for sport together with poor regulation of the spring hunting season (which is intended to coincide with passage migration and avoid targeting locally breeding birds) is a significant and increasing threat; large numbers were reportedly shot in the Kievka River basin, southern Primorye, in spring 2008⁶. Threats in its Chinese breeding range include dam construction, deforestation, illegal hunting, human disturbance and the use of poisons and/or explosives for fishing⁴. Fine meshed nets were a significant threat to the post-breeding congregations at Song Jiang He in Jilin Province, China, but illegal fishing at the site has been reduced and only large meshed nets are used in legal fish-farming⁴. The site remains threatened by industrial pollution⁴. The proposed Korean Grand Canal project, which aims to canalise 3,134 km of the Korean peninsula's river and would radically alter the Han and Nakdong rivers (which currently support an estimated 30-50 birds in winter), was suspended in June 2008 but has not yet been cancelled⁸.

Conservation measures underway CMS Appendix II. Primary forest is protected at some breeding localities in China and at the most important breeding site in North Korea. A small proportion of its breeding and non-breeding populations occurs inside protected areas, notably Sikhote-Alin' State Biosphere Reserve, Lazovskiy State Reserve and Botchinskiy State Reserve⁶ (Russia), and Changbai Shan Nature Reserve (China). An artificial nest programme in Russia has shown positive results, increasing habitat capacity along rivers with logged flood-plains⁶. An information and education programme was started in Russia in 2006⁶.

Conservation measures proposed Delineate the breeding range in Russia. Survey breeding populations in the Bikin river basin and locate rivers with a high density of breeding pairs within the main breeding range (Primorye and Khabarovsk Region). Continue to monitor population trends. Carry out research into the impacts of human activities. Identify and protect key wintering areas in China and Korean peninsula. Establish new protected areas at important breeding localities, notably the Bikin and Iman river basins (Russia). Promote forestry management that maintains primary forest along rivers. Implement an artifical nest programme on key rivers. Initiate education programmes to raise public awareness and reduce levels of illegal hunting.

References BirdLife International (2001). 1. Duckworth and Chol (2005). 2. Solovieva et al. (2006). 3. Robson (2003). 4. Peiqi Liu in litt. (2007, 2008). 5. He Fen-qi et al. (2002). 6. D. Solovieva in litt. (2007, 2008). 7. L. Cao & M. Barter in litt. (2008). 8. Moores (2008). 9. Yu Chang-Hao et al. (2008).

Further web sources of information

Fully detailed species accounts from the Threatened birds of Asia: the BirdLife International Red Data Book (BirdLife International 2001), together with new information collated since the publication of the Red Data Book

Text account compilers Phil Benstead (BirdLife International), Jeremy Bird (BirdLife International), Simba Chan (Wild Bird Society of Japan), Mike Crosby (BirdLife International), Nic Peet (BirdLife International), Andy Symes (BirdLife International)

Contributors Mark Barter, Lei Cao, Fen-Qi He (Institute of Zoology, Academia Sinica, Beijing), Baz Hughes (Wildfowl and Wetlands Trust), Liu Peiqi, Diana Solovieva (Wrangel Island State Reserve)

IUCN Red List evaluators Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International), Andy Symes (BirdLife International)

Recommended citation BirdLife International (2009) Species factsheet: Mergus squamatus. Downloaded from http://www.birdlife.org on 10/2/2010

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

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