Chinese merganser (Scaly-sided merganser)

Mergus squamatus

Chinese zaagbek (Geschubde zaagbek) / Schuppensäger

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 (IUCN, 2012).

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.

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 the 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 rivers (Solovieva et al. 2006). It prefers freshwater habitats in winter, only c.10% are known to winter on coastal waters (Solovyeva et al. in press). On passage and in winter it feeds along large rivers. Flocks of up to 20 individuals have been noted on passage or in winter (Duckworth and Chol 2005). In Russia, they moult on a range of water bodies within the breeding range and north and east of breeding range, including rivers, estuaries and the sea (Solovyeva et al. in press).

Conservation Actions Underway
CMS Appendix II. Primary forest is protected at some breeding localities in China and at the most important breeding site in North Korea. Small proportions of its breeding and non-breeding populations occur inside protected areas, notably Sikhote-Alin' State Biosphere Reserve, Lazovskiy State Reserve and Botchinskiy State Reserve (Russia) (D. Solovyeva in litt. 2007, 2008), and Changbai Shan Nature Reserve (China). An artificial nest programme in Russia, involving the provision of at least 180 nest boxes (Cranswick 2010), has shown positive results, increasing habitat capacity along rivers with logged flood-plains (D. Solovieva in litt. 2007, 2008; Anon. 2009). The programme involves the continued maintenance of artificial nests, liaison with hunters and fishers and collaboration with local communities, including information and education activities and the construction of a research and visitor centre (D. Solovyeva in litt. 2007, 2008; Anon. 2009). This has already resulted in a change in fishing practices by local people. It has also facilitated the capture of females for tagging with geolocators, allowing the identification of staging and wintering sites (Cranswick 2010, Solovyeva et al. in press).

Conservation Actions Proposed
Delineate the breeding range in Russia. Survey breeding populations 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 the Korean peninsula. Establish new protected areas at important breeding localities, notably the Bikin and Iman river basins (Russia). Establish seasonal protected area at moulting sites. Promote forestry management that maintains primary forest along rivers. Implement an artificial nest programme on key rivers. Initiate education programmes to raise public awareness and reduce levels of illegal hunting.

More information: http://www.iucnredlist.org/details/22680488/0

Above: adult male in breeding plumage

Above: adult birds, male in front

Above: adult birds, male right

Above: adult male in moulting plumage.

Above: juvenile male

Above: juvenile female

Above: female Chinese merganser