Scaly-sided Merganser

Common Name	Scaly-sided MerganserBirdlife International
Species name	Mergus squamatusBirdlife International
Family	Anatidae
Genus
Local Name	Country Appearance Local name Brunei Darussalam     Cambodia     China     Indonesia     Japan Yes コウライアイサ Lao PDR     Malaysia     Mongolia     Myanmar     Philippines     Republic of Korea     Singapore     Thailand     Vietnam

 

Visual and Sound Image

Photos

Scaly-sided Merganser

Videos

 

Sounds

 

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 species> Male Red-breasted Merganser M. serrator has white collar and rufous breast and lacks heavy scaling on flanks. Female also lacks scaling.

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Range Description

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.

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Ecology

Ecology (Behaviour)

See Habitat

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Habitat

<Breeding> 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.
<Non-breeding> On passage and in winter it feeds along large rivers. Flocks of up to 20 individuals have been noted on passage or in winter1.

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Diet

No descriptions

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Breeding Site

See Habitat

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References

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).

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Status

International Status

IUCN Red List Category

EN

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.
<Population justification> BirdLife International (2001) estimated 1,000-2,499 mature individuals. Although this estimate is precautionarily retained here, recent extrapolations from the breeding grounds based on increased co-efficients from studied breeding rivers and observations of pre-breeding adult and immature birds led to a population estimate of 8,000-10,000 individuals (D. Solovieva in litt. 2007).
<Trend justification>A rapid and on-going decline is suspected based on surveys of the Russian population (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), and declines have continued within the Chinese breeding population.

 

National Status

Country	Category	Reference
Brunei Darussalam
Cambodia
China	R	China Red Data book of Endangered Animals(1998) （Extinct, Extirpated, Endangered, Vulnerable, Rare, Interninate）
Indonesia
Japan
Korea	EN	Korean Red List of Threatened Species(NIBR, 2012)
Lao PDR
Malaysia
Mongolia
Myanmar
Philippines
Singapore
Thailand	VU	Thailand Red Data: Birds(Sanguansombat, 2005)
Vietnam	R	Red Data Book of Vietnam(2000) （Endangered, Vulnerable, Rare, Threatened）

 

Management

Threat

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.

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Information

No descriptions

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Current Conservation

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.

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Current Conservation

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.

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Legal Protection

Country	Status	Reference
Brunei Darussalam
Cambodia
China
Indonesia
Japan
Korea	Category II	Wildlife Protection Act
Lao PDR
Malaysia
Mongolia
Myanmar
Philippines
Singapore
Thailand
Vietnam

 

Related Links

• CMS: Convention on Migratory Species

Range

Geographical Information

Migration Route

 

Asian Waterbird Census

Descriptions

The Asian Waterbird Census (AWC) was initiated in 1987 and runs in parallel with other waterbird censuses carried out in Africa, Europe, Central and West Asia and Latin America under the umbrella of the International Waterbird Census (IWC), which is organised by Wetlands International.

The AWC takes place annually, during the second and third weeks of January, and is carried out by volunteers interested in collecting information on waterbirds and wetlands as a basis for contributing to their conservation.

Reference: Li, Z.W.D., Bloem, A., Delany S., Martakis G. and Quintero J. O. 2009. Status of Waterbirds in Asia - Results of the Asian Waterbird Census: 1987-2007. Wetlands International, Kuala Lumpur, Malaysia

Census Data

BRUNEI DARUSSALAM	1986	1987	1988	1989	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	2002	2003	2004	2005	2006	2007
The number of observed individual
The number of observed sites(not all count sites)
The total number of count sites	2	3	3	2	4	4	0	4	4	4	4	5	5	0	0	0	9	0	0	1	0	9
CAMBODIA	1986	1987	1988	1989	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	2002	2003	2004	2005	2006	2007
The number of observed individual
The number of observed sites(not all count sites)
The total number of count sites	0	0	0	0	0	0	0	4	0	0	11	0	0	12	12	11	5	1	6	9	6	6
CHINA	1986	1987	1988	1989	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	2002	2003	2004	2005	2006	2007
The number of observed individual					22	24	9				18				100	18			31
The number of observed sites(not all count sites)					3	3	2				1				1	1			2
The total number of count sites	0	1	34	12	50	60	67	29	6	14	6	15	21	20	14	10	22	45	80	81	59	72
INDONESIA	1986	1987	1988	1989	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	2002	2003	2004	2005	2006	2007
The number of observed individual
The number of observed sites(not all count sites)
The total number of count sites	0	0	0	1	19	8	17	17	15	19	16	0	0	47	12	10	40	34	14	16	15	23
JAPAN	1986	1987	1988	1989	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	2002	2003	2004	2005	2006	2007
The number of observed individual											14
The number of observed sites(not all count sites)											1
The total number of count sites	0	0	0	53	39	52	47	20	50	40	47	37	41	37	107	112	103	109	97	159	142	137
LAO PDR	1986	1987	1988	1989	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	2002	2003	2004	2005	2006	2007
The number of observed individual
The number of observed sites(not all count sites)
The total number of count sites	0	0	0	2	4	5	3	2	1	0	0	0	0	0	14	1	0	0	0	1	0	0
MALAYSIA	1986	1987	1988	1989	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	2002	2003	2004	2005	2006	2007
The number of observed individual
The number of observed sites(not all count sites)
The total number of count sites	0	0	0	59	68	93	85	17	10	7	10	0	0	20	25	25	25	43	43	82	82	40
MYANMAR	1986	1987	1988	1989	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	2002	2003	2004	2005	2006	2007
The number of observed individual
The number of observed sites(not all count sites)
The total number of count sites	0	5	3	12	17	15	21	20	13	12	2	4	2	0	7	32	47	73	24	31	32	19
PHILIPPINES	1986	1987	1988	1989	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	2002	2003	2004	2005	2006	2007
The number of observed individual
The number of observed sites(not all count sites)
The total number of count sites	0	0	0	0	19	21	34	39	46	47	39	28	29	32	43	38	50	47	56	54	65	108
SINGAPORE	1986	1987	1988	1989	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	2002	2003	2004	2005	2006	2007
The number of observed individual
The number of observed sites(not all count sites)
The total number of count sites	0	0	0	0	4	12	17	15	13	14	10	10	6	11	10	10	8	9	9	8	8	7
REPUBLIC OF KOREA	1986	1987	1988	1989	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	2002	2003	2004	2005	2006	2007
The number of observed individual																13	2		1	18	51	20
The number of observed sites(not all count sites)																2	1		1	3	3	2
The total number of count sites	0	0	10	12	22	20	20	15	10	22	25	22	14	68	99	112	118	116	117	123	127	127
THAILAND	1986	1987	1988	1989	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	2002	2003	2004	2005	2006	2007
The number of observed individual						1
The number of observed sites(not all count sites)						1
The total number of count sites	10	8	3	20	26	12	23	16	17	5	9	3	1	1	7	3	9	26	20	82	99	33
VIETNAM	1986	1987	1988	1989	1990	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	2002	2003	2004	2005	2006	2007
The number of observed individual
The number of observed sites(not all count sites)
The total number of count sites	0	0	0	1	2	0	1	4	0	1	1	0	1	8	2	2	16	4	4	9	6	11

 

Population

Descriptions

 

Population Trend

 

Additional Information

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Climate change species distributions

 

Other Information

• 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