About ten days ago we experienced a cold snap in Beijing with temperatures down to about -20 degs C at night. This spell meant that most, if not all, fresh water bodies, such as reservoirs and lakes, were locked in ice, forcing waterbirds to move to the rivers which remained relatively ice-free due to the flow. During such weather, it’s a good time to visit the local river – the Wenyu – on the border of Chaoyang and Shunyi Districts. Last week I recorded over 300 Common Merganser (普通秋沙鸭, Pǔtōng qiū shā yā) along a relatively short stretch of the river, as well as Goldeneye (鹊鸭, Què yā), Smew (白秋沙鸭, Báiqiū shā yā) and even a Coot (骨顶鸡 Gǔ dǐng jī), surprisingly scarce on the Wenyu River. Encouraged by this, I decided to make another visit on Saturday afternoon.
The best part of the river, although only about 1km from my apartment as the Coot flies, is around 4-5km away by road given the layout and position of the bridges, so I had planned to get a taxi and then walk the best section, before walking back. However, given the semi-lockdown in my district due to a handful of new COVID-19 cases, no taxis or DiDis are allowed to operate in the area, so I decided to walk, taking in a section of the river that I don’t normally focus on. Having reached the river, I was expecting to walk c3km without seeing much before reaching what’s known as the lower weir. How wrong I was!
About 1km along, I noticed a small group of Mallard (绿头鸭 Lǜ tóu yā). I scanned them with my binoculars in case a Gadwall (赤膀鸭, Chì bǎng yā) or Falcated Duck (罗纹鸭, Luówén yā) was lurking.. but instead, to my surprise, I saw a female merganser. Clearly smaller than Common Merganser (普通秋沙鸭, Pǔtōng qiū shā yā) and lacking the sharp contrast between the brown head and neck and the white throat of Common Merganser, the bird that popped into my mind was Scaly-sided Merganser (中华秋沙鸭, Zhōnghuá qiū shā yā), an endangered species with fewer than ten records in Beijing and a species that I had never seen in the capital. Having left my telescope at home, as I would be walking so much, I needed to get closer to rule out the other possibility – Red-breasted Merganser (红胸秋沙鸭, Hóng xiōng qiū shā yā). The latter is a scarce species in Beijing but much more frequent than its endangered cousin. Sneaking closer, using the cover of a few trees, I was able to see the bird clearly and, immediately, I could see the diagnostic scaly markings on the flanks and a yellow tip to the bill. It was a Scaly-sided Merganser!
Having not expected to see much along the first stretch of river, I had not yet unpacked my camera from my backpack (schoolboy error) and so I slowly removed my backpack and crouched, all the time keeping one eye on the merganser in case my movement caused it to fly. Fortunately, I was able to extract my camera and take a few images to document the sighting. As I sat quietly, remarkably, the merganser swam towards me and stood on a barely submerged patch of mud to preen. I watched it for several minutes, gripped by the presence of this globally rare bird, before a dog walking couple came by and, checking out my presence, their two dogs barked loudly and scared the group of duck, including all the Mallard and, of course, the merganser.
All of the birds flew upstream, the direction I was heading, and it was perhaps only five minutes later that I reconnected with the group, including the merganser. Again I watched the Scaly-sided Merganser at reasonably close quarters before a fisherman, walking along the edge of the river bank looking for the best spot from which to fish, came a little too close and the merganser was again flushed and flew upstream.
Although I didn’t have my telescope with me, I was elated with the views and had secured some record images that at least documented the record.
Scaly-sided Merganser is a species that I have had on my radar for some time when walking the Wenyu River in winter. Although there are only around ten records from the capital in total, the Wenyu bird is perhaps surprisingly the third record this winter, all of which have been females. A female was photographed in Tongzhou (part of the same river) on 31 December 2020 and it, or another, was at the Summer Palace on 10 January and has been seen on and off since that date. Whether all of the sightings relate to the same individual, or whether two or even three birds are involved, is an open question. Interestingly, the Scaly-sided Merganser did not seem to associate with Common Merganser, several groups of which were on the river, instead preferring to be on its own or loosely associating with Mallard.
The sighting takes on greater significance given the plans to ‘develop’ the Wenyu River, including raising the water level by several metres and running a tourist ‘cruiser’ along part of the river in summer. Academics are working with the local government to try to ensure the plans take into account the needs of biodiversity, especially waterbirds, particularly in winter. This will include ‘zoning’ to set aside some undisturbed areas for waterbirds and to protect the breeding habitat of egrets and herons in summer. Having records of an endangered species along the river will strengthen the case of the academics.
Scaly-sided Merganser (中华秋沙鸭, Zhōnghuá qiū shā yā) is a rare East Asian endemic, breeding along montane rivers in mixed forest in the Russian Far East, NE China and probably DPRK, and wintering in the Republic of Korea and central and E China. It is probably more frequent in Beijing than we realise and the fact that all of the capital’s confirmed records bar one have come in the last five years suggests greater observer coverage is a factor. We can expect more records as birding continues to grow in popularity. Scaly-sided Merganser is classified as ‘endangered’ by the IUCN Red List.
Title image: Scaly-sided Merganser along the Wenyu River, 16 January 2021 (Terry Townshend)