Crested Shelduck

The Crested Shelduck is a waterfowl species native to Northeast Asia. Initially, it was believed to be a hybrid of the Ruddy Shelduck and the Falcated Duck, but subsequent specimen studies have debunked this theory, establishing it as a distinct species¹. Recent studies classify the Crested Shelduck as a unique evolutionary branch within the genus Tadorna, closely related to the Paradise Shelduck (T. variegata) and the Australian Shelduck (T. tadornoides)². The Crested Shelduck is one of the most endangered waterfowl species, with no confirmed wild sightings for many years, making it highly likely to be extinct.

The Crested Shelduck is slightly larger than other similar wild shelducks. It is sexually dimorphic, with both sexes featuring prominent crests extending to the back of the neck, which gives the species its name. Males have a crest that is a deep, bronzed black-green color, a chest of a similar hue, a smoky gray head and neck, and a darker gray abdomen. Females have a black crest with two white eye rings near the ears, a white head and neck, and a slightly darker, brownish body compared to the males. Both sexes have white patches on their wings and pale red bills and legs.

Little is known about the habits of the Crested Shelduck. Based on sightings and speculation, their breeding grounds are believed to be in Northeast Asia, primarily the Russian Far East, as well as the mountainous regions bordering Northeast China and the Korean Peninsula. Their wintering areas include the coasts and islands of the Sea of Japan and the Yellow Sea. The known habitats of the Crested Shelduck are mainly mountainous and forested areas, as well as river estuaries.

The Crested Shelduck is a mysterious waterfowl, never widely distributed in modern times, with sightings being sporadic. Some hypothesize that it is a relict species that was more widespread in prehistoric times, but there is no solid fossil evidence to support this. Japanese literature and paintings from the Edo period (17th to 19th centuries) frequently mention the Crested Shelduck under the name “Korean Mandarin Duck,” possibly indicating a significant population in the Korean Peninsula during that time³. The reasons for the population’s decline to the point of probable extinction are unclear, but human hunting and habitat degradation due to agricultural development are suspected.

The last confirmed wild sighting of the Crested Shelduck was on May 16, 1964, when Russian researchers observed three individuals near the Rimsky-Korsakov Islands southwest of Vladivostok, mingling with a flock of Harlequin ducks⁴. In March 1971, there was a sighting of two males and four females in North Hamgyong Province, North Korea⁵. There were also a series of unverified sightings in Northeast China during the 1980s⁶.

Appearance #

• Male
  • The crest is a deep black-green extending to the back of the neck and forehead, and continues downward covering the eyes.
  • The sides of the head and neck are smoky gray with irregular brown streaks, and there are black spots on the cheeks.
  • The chest and back of the neck are similar in color to the crest, transitioning to dark gray on the lower chest.
  • The back, lower chest, and abdomen are dark gray with irregular fine gray-white lines.
  • The coverts are white, the flight feathers are black, and the secondary flight feathers have a metallic green sheen.
  • The upper tail coverts and tail feathers are black, while the under-tail coverts are brown.
  • The bill and legs are orange-red.
• Female
  • The crest is black, also extending to the back of the neck and forehead, but forms rings around the eyes, surrounding white patches consistent with the cheeks’ color.
  • The neck and upper chest are white, the chest and back of the neck are gray with fine white stripes, and the abdomen is a comparatively lighter gray.
  • Feather characteristics are generally similar to the male⁷.

The appearance of juveniles is unknown.

Life History #

Breeding and Rearing #

The breeding behavior of the Crested Shelduck is not well understood. It is speculated that they nest in mountainous coniferous forests, some distance from riverbanks, either in tree cavities or rock crevices (Japanese historical texts sometimes refer to this bird as “rock mandarin duck”). The Crested Shelduck has historically had a small population, which may be related to specific breeding and rearing characteristics. For example, during the migration from high-altitude rock nests to nearby water bodies, the mortality rate of ducklings might be high⁸. Their hatching success rate may also be relatively low.

Other breeding behaviors of the Crested Shelduck might be similar to other shelducks, breeding from spring to early summer. Males guard the nesting sites while females incubate the eggs. After rearing the young for a period in the breeding area, they migrate to water bodies and then to coastal areas for the winter. They may be monogamous, pairing for life⁹.

Diet and Behavior #

The structure of the Crested Shelduck’s bill suggests that they are not adept at filtering water for insects and may primarily be herbivorous, feeding mainly on grasses found in forests and near water bodies. Ducklings might be omnivorous, feeding on insects and other small creatures⁸.

Crested Shelducks often form small flocks of 3-5 to over a dozen individuals, as confirmed by sporadic observation records. These small family groups likely gather during the molting period around late August¹⁰. During migration, they may also join other ducks with overlapping ranges and similar migratory habits.

The Crested Shelduck is likely nocturnal⁸, inhabiting high-latitude, sparsely populated forested areas during the breeding season, migrating along rivers to coastal areas, estuaries, and large lakes for the winter¹¹.

Habitat #

It is speculated that the Crested Shelduck is a relict species from the Tertiary glacial period. They migrated south during the ice age and survived but could not adapt to warmer habitats, so they have remained in high-latitude forested areas in modern times⁸.

Confirmed modern habitats of the Crested Shelduck include:

• Islands in the Primorsky Krai, along the Sea of Japan (breeding)
  • The collection site of the Copenhagen female specimen (April 1877¹²), near Vladivostok
  • The sighting location of May 16, 1964⁴, on isolated rocky islets near the Rimsky-Korsakov Islands
• Southern waters of the Korean Peninsula, including the coasts of the Sea of Japan and East Sea, and inland rivers and large lakes (wintering)
  • The collection site of the Japanese female specimen (December 1916⁸), downstream of the Nakdong River, near Busan
  • The collection site of the Japanese male specimen (November to early December 1913 or 1914⁸), along the Geum River in Jeollabuk-do¹³

Potential modern habitats include:

• Hokkaido region in Japan (breeding)
  • In October 1822, a pair of live Crested Shelducks were captured near Kameda, Hakodate, Hokkaido¹²
• Mountainous and forested areas in northern North Korea (breeding)
  • The sighting location of March 1971⁵, at the estuary in North Hamgyong Province
  • In March 1916, a hunter claimed to have captured a Crested Shelduck in present-day North Pyongan Province, North Korea⁸
• Remote mountainous areas and river estuaries in Northeast China (breeding)
  • Multiple sightings in the 1970s and 1980s, mainly at river estuaries, sandy shores, and mountainous areas such as the Greater Khingan Range⁶

Additionally, there have been some less reliable sightings in inland China. In 1936, there was a report of three Crested Shelducks being shot in Rehe (now Chengde), but the specimens were not preserved⁸. After the 1980s, there were reports from Zhaotong in Yunnan, but this seems too far from the presumed habitat range, making these reports less credible⁶.

From the above information, we can roughly outline the modern habitat range of the Crested Shelduck: breeding in remote mountainous and forested areas of the Russian Far East, northern North Korea, northeastern China, and Hokkaido, Japan, inhabiting riversides and estuaries. They migrate along the coastlines of the Sea of Japan and the Yellow Sea, with wintering areas along the coasts and islands of these seas, particularly in the waters of southern Korea¹⁴.

Sightings and Population Speculations of the Crested Shelduck After 1964 #

In late March 1971, O Myong Sok, leading about 20 biology students from Kim Il Sung University, observed six Crested Shelducks (two males and four females) at the estuary in North Hamgyong Province, North Korea. The birds briefly rested on the sea surface before flying northeast, presumably migrating from their wintering grounds to their breeding grounds⁵. This record aligns well with the Crested Shelduck’s presumed habits (small flock formation, habitat characteristics, breeding range, and timing of return to breeding grounds). However, the sighting has been questioned due to the technological level in North Korea at the time and the 13-year delay in reporting the observation. Despite these concerns, the presence of over 20 biology students at a distance of 40-50 meters adds credibility to the sighting, given the distinctive features of the Crested Shelduck that would prevent confusion with similar ducks. The delay in publication until 1984 may be linked to Dr. Nowak’s 1983 initiative to search for the Crested Shelduck.

Translation of the original observation record:

In late March 1971, I observed six Crested Shelducks (two males and four females) near the estuary of the Puchon River ¹⁵ (approximately 129°44’E, 41°3’N) near Chilbosan in Myongchon County, North Hamgyong Province. At the time, I was studying birds in this area with about 20 biology students from Kim Il Sung University. When I noticed the six ducks swimming on the water surface from a distance of 40-50 meters, the students were present, and we all observed the birds for a long time until they flew northeast. Unfortunately, we did not have a camera to document the sighting; however, by later comparing illustrations and descriptions, we had no doubt that they were Crested Shelducks. So far, I have not published this observation, but I have informed several biologists in the Democratic People’s Republic of Korea and presented it at academic meetings in our country. The relatively early sighting date (late March) may indicate that these birds were still migrating from their wintering waters to breeding grounds. The sighting of six Crested Shelducks at the Puchon River estuary in late March 1971 confirms the hypothesis that this relict species has not become extinct but exists in extremely small populations in East Asia. Given that most previous evidence of Crested Shelducks comes from the Korean Peninsula, their breeding grounds are likely in Korea, possibly in mountainous areas near the border with the People’s Republic of China. Due to the continued risk of complete extinction, the rescue actions proposed during the 18th International Ornithological Congress in Moscow in August 1982 (Nowak 1982) should be initiated as soon as possible.

Subsequent valuable sightings mainly come from Northeast China, reported by an investigation team led by Zhao Zhengjie. The disclosed sightings are listed chronologically as follows⁶:

1. Late October 1976¹¹, eight Crested Shelducks sighted on a sandy shore about 50 km from the estuary of the Yalu River, reported by an experienced hunter.
2. April 1983, one female Crested Shelduck sighted in the Greater Khingan Range, reported by a specimen collector.
3. Spring 1984, four Crested Shelducks sighted, with two shot by hunters in the Dashitou Forestry Bureau, Changbai Mountains.
4. Autumn 1984, five Crested Shelducks sighted by a bird enthusiast in Ji’an, Yalu River.
5. Spring 1986, a pair of Crested Shelducks sighted by a hunting enthusiast in a tributary of the Tumen River in the forest.
6. April 1986, two Crested Shelducks sighted by a bird enthusiast (same person in record 3) in Ji’an, Yalu River.
7. May 1987, one Crested Shelduck sighted by a forester with over 20 years of experience hunting wild ducks in a forest river in the Greater Khingan Range.
8. Spring 1988, one Crested Shelduck sighted from a distance (unconfirmed) by an ornithologist with over 30 years of field investigation experience in the Naitou River, Changbai Mountains.

The observer of record 8 is the most reliable in terms of bird field identification experience, but unfortunately, the sighting was not confirmed by observer due to the distance. Thus, the latest sighting in Northeast China is from 1987. Although the reliability of individual sightings cannot be fully confirmed, the multiple records of habitat and timing consistent with the Crested Shelduck’s known habits suggest that the hypothesis of its survival into the 1990s and beyond is plausible. According to Zhao Zhengjie’s speculation⁶, the population is fewer than 50 individuals, distributed in the forested areas and riverine habitats of the Changbai Mountains and the Greater and Lesser Khingan Ranges.

From the sightings and conservation activities related to the Crested Shelduck, several issues are apparent. The Crested Shelduck population has always been critical, and scientists have debated its extinction status, leading to a lack of consensus on systematic search and conservation efforts. Dr. Nowak’s 1983 call to action received a response, but the efforts appear to have been primarily mobilizing local residents to collect sightings rather than organizing large-scale searches of potential habitats by researchers. Given the Crested Shelduck’s habits and distribution, a comprehensive search would require significant funding and personnel, as well as international coordination. In the late Cold War period, such large-scale cooperative searches in Northeast Asia were impractical¹⁶.

In China, the Crested Shelduck has never been recognized in the “National Key Protected Wild Animals List” (国家重点保护野生动物名录) which start to be issued since 1989¹⁷, possibly because its distribution in China itself requires further evidence. Despite a series of sightings, there has been no direct and conclusive scientific evidence. Various factors have prevented this extremely endangered and beautiful bird from receiving adequate targeted protection.