Plight of the Scaly-sided Merganser

Posted on: April 17, 2014

Author: Young-jin Kim



Courtesy of Robin Newlin / Birds Korea

Degradation of Korean rivers posing challenge to endangered bird, experts say

By Kim Young-jin

With a bright orange bill and exquisite, maze-like patterns on its flanks, the Scaly-sided Merganser is a bird that should be hard to ignore.

But many appear to be overlooking the endangered East Asian duck, most of which spend warm months in Russia and winters in more temperate places including Korea.

Due to hunting, pollution and ecological degradation, the number of these shy but stunning creatures has dwindled to only some 4,600, scientists estimate.

Their plight is clearly illustrated in Korea, where conservationists say development of rivers has robbed them of crucial places to feed and rest.

Before: This image of Banbyeon Stream, a main tributary of the Nakdong River near Andong, North Gyeongsang Province, was taken in February
2012 and shows a typical ecosystem where Scaly-sided Merganser can feed and rest. / Courtesy of Birds Korea
After: This image, taken from roughly the same location in March 2013, illustrates changes caused by refurbishment of the country’s waterways.
/ Courtesy of Birds Korea

Some 150 of the merganser are believed to spend the winter here, and others temporarily stop over. While there is little data about the bird, conservationists believe their number here is dropping.

They argue that the bird, because it relies on access to natural rivers, is an indicator of how healthy the country’s river ecosystems are.

“Their rarity already indicates how few natural rivers remain,” said Nial Moores, director of the conservation group Birds Korea.

“If nothing is done to stop the degradation of rivers, we will lose this species and a multitude of others — plant and animal.”

The situation puts more scrutiny on former President Lee Myung-bak’s efforts to refurbish the nation’s four major rivers.

The $17.3 billion “Four Rivers Project” involved massive dredging and construction despite concerns that the administration had not sufficiently studied potential environmental impacts.

A probe by the Board of Audit and Inspection in 2013 found that the Lee Myung-bak administration’s signature Four Rivers Project had been
poorly executed and caused problems to water quality.
/ Courtesy of Birds Korea

*               *               *

In summer, most Scaly-sided Merganser stay near rivers in Russia’s southeastern Sikhote-Alin mountain range, nesting in the cavities of old trees.

It’s then that the male, with his crest of long black feathers, and the female, with her chestnut-colored head, perform mating rituals and breed.

When a chill hits the air, they begin migrating to warmer areas, to rivers that won’t freeze over — where they can dive for food.

For many, this leads to southern and central China. To get there, they fly south in flocks of up to 20 birds, toward the East Sea before crossing the peninsula.

Diana Solovyeva is a Russian scientist who has tracked merganser by attaching small transmitters to their legs. The world’s leading expert on the bird, she says most stop to rest on rivers in South Korea.

Another group stays the entire season here.

Courtesy of Robin Newlin / Birds Korea

“South Korea is one of the most important staging areas for the Scaly-sided Merganser. But it’s also one of the most important wintering areas,” said Solovyeva, adding that some winter in North Korea as well.

The scientist manages a Scaly-sided Merganser task force for the East Asian Australasian Flyway Partnership (EAAFP) an international network of groups seeking to protect migratory birds.

“The destruction of these (river) areas would mean losing the opportunity to feed.”

Despite its beauty, it’s only recently that the bird has attracted interest here. The earliest recorded sighting here came in 1927. Since then, recorded sightings were extremely rare until the early 2000s.

*               *               *

When it arrives for winter, the Merganser seeks out faster-flowing stretches of water that don’t freeze and are clear enough for the bird to see its prey.

The easily-spooked creature also tends to choose areas away from roads or foot traffic. When they sense a potential threat — even as far away as 250 meters — they tend to fly upstream and stop feeding.

Originally, Korea was rife with ideal stretches, as rivers flowed down from mountains, giving them a quick pace.

But the areas began disappearing as the country built dams and railroads that ran alongside the water. The situation worsened with the start of the Four Rivers Project, said Moores.

The Lee administration argued that due to torrential summer rainfall and dry winters, the country was at risk of flooding and drought.

The project, by building dams and weirs and dredging some 700 kilometers of rivers, aimed to reduce water levels and secure abundant water resources.

Lee also sought to make the areas into “Rivers of Culture” by creating thousands of kilometers of bicycle lanes, walkways and sports facilities.

Fears that the project had been implemented hastily were confirmed last year when the Board of Audit and Inspection (BAI) said several problems had emerged since its completion.

Nearly all the dams had suffered damage due to high water pressure, the BAI said. Levels of both contamination and algae had elevated — problems blamed on “poor planning and lack of time.”

*               *               *

Statistics from the Ministry of Environment on the number of merganser in Korea vary widely over the past decade. The number jumps, for example, from one bird in 2004 to 51 just two years later.

NGO estimates are higher but groups believe the number is falling.

Birds Korea, supported by EAAFP, counted 149 individuals during a nationwide survey in January this year. The survey was more extensive than a previous one in 2012, when they found the same number of birds.

“This is clearly suggesting that the bird is declining,” said EAAFP science officer Judit Szabo. “If you survey more extensively, you should find more birds.”

The conservationists said the removal of riverside vegetation and construction of bicycle trails made it difficult for merganser to rest and feed without being disturbed.

Because of dredging and dam construction, the rivers are more prone to freezing. They are also muddier, making it harder for the bird to find the fish it needs.

During the most recent survey, Birds Korea traveled along the North Han, Geum, Yeongsan and Nakdong and other rivers.

Along one stretch near Andong, North Gyeongsang Province, the group counted 10 mergansers in 2012. This year, it reported seeing none.

It also found none on parts of the Geum River near Daejeon, though the species had been regular there in the early 2000s.

“In areas where there is increased infrastructure, we tend strongly to see a reduction in the number of Scaly-sided Merganser and other sensitive water bird species,” Moores said.

Kim Jin-han, director of international cooperation for the state-run National Institute for Biological Resources, largely agreed with the concerns of conservationists.

But he downplayed the link between the refurbishment of major rivers and the bird’s decline, saying it preferred to stay on narrow water ways.

Others argued, however, that damming and dredging of big rivers would have a significant impact on the entire ecosystem including tributaries.

*               *               *

Challenges facing the species are hardly limited to Korea, however. EAAFP’s Szabo likened their plight to a “death by a thousand cuts.”

She cited illegal hunting and logging of riverside forests in Russia, irresponsible net fishing in China and pollution in the region as major factors in the bird’s declining population.

“We can’t say it’s one particular thing, but rather a lot of things,” she said.

The experts agreed on the necessity of data collection and sharing among countries where the bird appears.

“For migratory birds, international cooperation is essential. It’s the same bird flying from country to country and we need to secure their lives at each stage,” Szabo said.

They said it is possible to mitigate some of the damage done to the ecosystems, for example by redirecting bike paths, restoring vegetation and minimizing human disturbance near areas the birds use.

The country should abide by precautionary principles and halt further development until a better understanding of the ecosystem exists, Moores said.

He added that public awareness should be fostered by putting up informational signs.

“This is a way the bird can survive and people can get familiar with it and understand the meaning of the species,” he said.

“It’s an indicator of healthy, East Asian rivers. It’s a magnificent, beautiful symbol of them.”

Comments are closed.