Scaly-sided Merganser Survey, January 31

Survey report by Jason Loghry with Lee Keesan, Choi Su-Yeon and Mike Friel

On Saturday, a team of us from Birds Korea surveyed the Southeast River for Scaly-sided Merganser. This is the same river that we monitored in the winter of 2011 / 2012 and again in 2013 / 2014. Our previous record high was of 56 individuals, in February of 2012. This season, we surpassed this high record by counting a total of 61 individuals, observed from ten different observation points along the river throughout the course of the day. These include 16 adult male, 42 redhead types (some of which were likely first-winter males), and 3 obvious first-winter males in more advanced stages of moult. Much of their behavior included roosting, feeding, and what looked like courtship behavior (“nod-swimming”). The biggest group observed was a flock of 22 together, which was mostly made up of redhead  types (18/22).

Scaly-sided Merganser Mergus squamatus © Lee Keesan

Scaly-sided Merganser Mergus squamatus © Lee Keesan

At two of these SSM wintering sites, major habitat changes have taken place. Land adjacent and in close proximity to the river has been converted to what looks like a construction site for making concrete, with machinery utilizing the nearby river water. At the second of these two sites, there are ongoing changes. Much of the previously rich river bank vegetation has been severely modified and is now gone. Scaly-sided Merganser is limited to stretches of river such as these, that contain both fast-flowing shallow water for feeding and slower-moving stretches with boulders and sandbanks used for loafing. With evidence that shows Scaly-sided Merganser is highly sensitive and susceptible to disturbance, how will changes like these impact this globally Endangered species?


Scaly-sided Merganser habitat changes on the Southeast River  © Jason Loghry

Scaly-sided Merganser habitat changes on the Southeast River © Jason Loghry

 The improvement of disturbance-management (by e.g. screening some stretches of river and by restricting access to others) could provide a quick and cost-effective method with which to enhance several stretches of river used by this and several other river species. – Nial Moores PhD, 28 February 2013

Scaly-sided Merganser Mergus squamatus © Choi Su-Yeon

Scaly-sided Merganser Mergus squamatus © Choi Su-Yeon

Scaly-sided Merganser has a very small global 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). Birds Korea has a special role in the work of Scaly-sided Merganser. Later this year, two of our members are likely to attend a conservation workshop on the species that will be held in Russia. If you would like to support our future work with Scaly-sided Merganser, please contact us at [email protected].  To read more about the work we’ve done with Scaly-sided Merganser, please visit our website here. Birds Korea would like to send a special thanks to Lee Keesan, Choi Su-Yeon, and Mike Friel for their participation in the survey.


The article was published by Birds Korea at

To find out more about Scaly-sided Merganser, please clink here.


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