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Scaly-sided Merganser Mergus squamatus

IUCN Red List Criteria

Critically Endangered  
Endangered C2a(ii) 
Vulnerable A2cd+3cd+4cd;C2a(ii) 

IUCN Red List history

Year Category
2012 Endangered
2009 Endangered
2008 Endangered
2007 Endangered
2006 Endangered
2004 Endangered
2002 Endangered
2000 Vulnerable
1996 Vulnerable
1994 Vulnerable
1988 Threatened

Species attributes

Migratory status full migrant Forest dependency High
Land mass type continent
Average mass -

Distribution

  Estimate Data quality
Extent of Occurrence breeding/resident (km2) 862,000 medium
Extent of Occurrence non-breeding (km2) 2,830,000 medium
Number of locations -
Fragmentation -

Population & trend

  Estimate Data quality Derivation Year of estimate
No. of mature individuals 2400-4500 medium Estimated 2010
Population trend Decreasing poor -
Number of subpopulations 1 - - -
Largest subpopulation 2400-4500 - - -
Generation length (yrs) 7.3 - - -
Population justification: In Russia, c.1,575 pairs nest in Sikhote-Alin (Solovyeva et al. in press). In China, 180-200 pairs breed in the Changbaishan Mountains (Liu et al. 2010) and perhaps 30-40 pairs in Lesser Xingan. In North Korea, probably less than 200 pairs breed, mainly on Mayang Chosuji reservoir (Chong and Morishita 1996). The total world population is therefore likely to consist of less than 3,000 pairs (Solovyeva in litt. 2012), however, there are other estimates of perhaps several thousand pairs (B. Hughes in litt. 2010). In recognition of this uncertainties, the number of mature individuals is estimated at 2,400-4,500, following Peiqi Liu et al. (2010). This is roughly equivalent to 3,600-6,800 individuals in total. Further research is required in order to verify this.
Trend justification: A rapid and on-going population decline is suspected (see BirdLife International 2001). The density of breeding pairs more than doubled since the 1960s/1970s in the species's stronghold in Russia, but has since stabilised (Solovieva et al. 2006). The Changbai (China) breeding population may be increasing, but the western population (found in Xingan, China and Zeya-Bureya, Russia) has declined rapidly.

Country/Territory distribution

Country/Territory Occurrence status Presence Breeding Non-breeding Passage Resident
China (mainland) Native Extant       Yes
Japan Native Extant   Yes    
Myanmar Native Extant   Yes    
North Korea Native Extant Yes      
Russia (Asian) Native Extant Yes      
South Korea Native Extant   Yes    
Taiwan (China) Native Extant   Yes    
Thailand Native Extant   Yes    
Vietnam Native Possibly Extinct        

Important Bird Areas where this species has triggered the IBA criteria

Country/Territory IBA Name IBA link
China (mainland) Baihe-Wanbao site factsheet
China (mainland) Cang Shan Er Hai Nature Reserve site factsheet
China (mainland) Changbai Shan Nature Reserve site factsheet
China (mainland) Dashanzuizi site factsheet
China (mainland) Dongting Hu wetlands site factsheet
China (mainland) Fenglin Nature Reserve site factsheet
China (mainland) Fujian Wuyi Shan Nature Reserve site factsheet
China (mainland) Gaoyou Hu site factsheet
China (mainland) Hanma Nature Reserve site factsheet
China (mainland) Heiyupao Nature Reserve site factsheet
China (mainland) Hukou Wetland Nature Reserve site factsheet
China (mainland) Huma He Nature Reserve site factsheet
China (mainland) Huzhong Nature Reserve site factsheet
China (mainland) Jingpo Hu Nature Reserve site factsheet
China (mainland) Keluo He Nature Reserve site factsheet
China (mainland) Laodengshan Nature Reserve site factsheet
China (mainland) Lashi Hai site factsheet
China (mainland) Liangshui Nature Reserve site factsheet
China (mainland) Mangui site factsheet
China (mainland) Maoshan Nature Reserve site factsheet
China (mainland) Mountains streams in Pingtang and Guiding site factsheet
China (mainland) Mudanfeng Nature Reserve site factsheet
China (mainland) Nansihu Nature Reserve site factsheet
China (mainland) Nanweng He Nature Reserve site factsheet
China (mainland) Naoli He Nature Reserve site factsheet
China (mainland) Nuomin-Bila He-Dayangshu site factsheet
China (mainland) Poyang Hu wetlands site factsheet
China (mainland) Qindeli Sturgeon Reserve site factsheet
China (mainland) Qingtongxia reservoir and Yellow River wetlands in Zhongning and Zhongwei site factsheet
China (mainland) Qixing He Wetland Nature Reserve site factsheet
China (mainland) Qixing Lazi Siberian Tiger Nature Reserve site factsheet
China (mainland) Rongcheng Swan Nature Reserve site factsheet
China (mainland) Sanjiang Nature Reserve site factsheet
China (mainland) Shaobo Hu Lake Area site factsheet
China (mainland) Shuifeng Reservoir and middle reaches of Yalu Jiang site factsheet
China (mainland) Songhua Hu, Baishan Hu and Hongshi Hu site factsheet
China (mainland) Tailai Dongfanghong site factsheet
China (mainland) Wuyuan Forest site factsheet
China (mainland) Xinjiang Yiyang Qinghu Section site factsheet
China (mainland) Xunbiela He Nature Reserve site factsheet
China (mainland) Yancheng Nature Reserve site factsheet
China (mainland) Yangdali Nature Reserve site factsheet
China (mainland) Yellow River Delta Nature Reserve site factsheet
China (mainland) Yinchuan plain site factsheet
China (mainland) Yueya Hu Nature Reserve site factsheet
China (mainland) Yunfeng Reservoir site factsheet
China (mainland) Zhejiang Qingliangfeng Nature Reserve site factsheet
North Korea Mayang reservoir (Mayang Chosuji) site factsheet
North Korea Mount Paekdu site factsheet
North Korea Orangchon River estuary site factsheet
Russia (Asian) Khanka plain site factsheet
Russia (Asian) Kievka and Chernaya river basins site factsheet
Russia (Asian) Lower Tumen river site factsheet
Russia (Asian) Middle reaches of the Bikin river site factsheet
Russia (Asian) Middle reaches of the Iman river site factsheet
Russia (Asian) Sikhote-Alin' Nature Reserve site factsheet
Russia (Asian) Udyl' lake site factsheet

Habitats & altitude

Habitat (level 1) Habitat (level 2) Importance Occurrence
Forest Temperate major breeding
Marine Neritic Estuaries suitable non-breeding
Marine Neritic Subtidal Sandy suitable non-breeding
Wetlands (inland) Permanent Freshwater Lakes (over 8ha) suitable non-breeding
Wetlands (inland) Permanent Rivers/Streams/Creeks (includes waterfalls) major breeding
Wetlands (inland) Permanent Rivers/Streams/Creeks (includes waterfalls) major non-breeding
Altitude 0 - 900 m Occasional altitudinal limits  

Threats & impact

Threat (level 1) Threat (level 2) Impact and Stresses
Biological resource use Fishing & harvesting aquatic resources / Unintentional effects: (subsistence/small scale) [harvest] Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Decline Low Impact: 5
Stresses
Species mortality
Biological resource use Hunting & trapping terrestrial animals / Intentional use (species is the target) Timing Scope Severity Impact
Ongoing Minority (<50%) Rapid Declines Medium Impact: 6
Stresses
Species mortality
Biological resource use Logging & wood harvesting / Unintentional effects: (large scale) [harvest] Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Decline Medium Impact: 6
Stresses
Ecosystem degradation, Ecosystem conversion
Human intrusions & disturbance Work & other activities Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Decline Low Impact: 5
Stresses
Species disturbance
Natural system modifications Dams & water management/use / Dams (size unknown) Timing Scope Severity Impact
Future Minority (<50%) Slow, Significant Decline Low Impact: 3
Stresses
Ecosystem degradation, Ecosystem conversion
Pollution Agricultural & forestry effluents / Soil erosion, sedimentation Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Decline Low Impact: 5
Stresses
Ecosystem degradation
Pollution Industrial & military effluents / Type Unknown/Unrecorded Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Decline Low Impact: 5
Stresses
Ecosystem degradation
Residential & commercial development Commercial & industrial areas Timing Scope Severity Impact
Past, Unlikely to Return Majority (50-90%) Rapid Declines Past Impact
Stresses
Ecosystem degradation, Ecosystem conversion
Transportation & service corridors Shipping lanes Timing Scope Severity Impact
Ongoing Minority (<50%) Rapid Declines Medium Impact: 6
Stresses
Indirect ecosystem effects, Species disturbance, Ecosystem degradation, Ecosystem conversion

Utilisation

Purpose Primary form used Life stage used Source Scale Level Timing
Food (human) Whole Adults and juveniles Wild Subsistence, National Non-trivial Recent
Sport Whole Adults and juveniles Wild Subsistence, National Non-trivial Recent

Recommended citation
BirdLife International (2014) Species factsheet: Mergus squamatus. Downloaded from http://www.birdlife.org on 31/08/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 31/08/2014.

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.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Key facts
Current IUCN Red List category Endangered
Family Anatidae (Ducks, Geese, Swans)
Species name author Gould, 1864
Population size 2400-4500 mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 862,000 km2
Country endemic? No
Links to further information
- Summary information on this species