The Mandarin duck (Aix galericulata) is a small, brightly colored perching duck that is native to East Asia. With its distinctive plumage, the mandarin duck is considered one of the most beautiful ducks in the world. Though mandarin ducks are not native to North America, small populations have been established in parts of the United States and Canada due to escapes and releases from captivity. In this article, we’ll take a closer look at the natural history of the mandarin duck, and examine whether stable breeding populations currently exist in the US.
Natural range and habitat of the mandarin duck
The mandarin duck is native to East Asia, with its natural breeding range extending across China, Japan, Korea, and eastern Russia. Within its native range, the mandarin duck primarily inhabits densely forested areas near lakes, ponds, rivers, and streams. Its preferred breeding habitat consists of quiet wooded ponds and lakes surrounded by trees. During the winter, mandarin ducks may also be found in coastal marshes, estuaries, and flooded fields.
Across its native range, mandarin ducks are highly local and generally occur at low densities. Japan likely hosts the world’s largest mandarin duck population, though population declines have been noted there in recent decades due to habitat loss. Overall, the mandarin duck is not considered a globally threatened species, though some local populations are vulnerable.
Description of mandarin ducks
The mandarin duck is a small duck, with lengths ranging from 41-49 cm (16-19 inches) and weights between 600-680 g (1.3-1.5 pounds). The adult male plumage is among the most ornate of all waterfowl. The head has a distinctive broad blue band around the eyes, with a green-glossed purple forehead, red bill, and wispy crest. The chest is purple with two vertical white bars, and the flanks ruddy-chestnut. Mantle feathers are grey-green with wide black margins. The sail feathers along the back are long and green-edged, forming a distinctive sail shape when erected. The female is much less brightly colored than the male, with a white eye-ring, grey head, brown body, and white-tipped orange bill.
Diet and behavior
Mandarin ducks are largely herbivorous, consuming grasses, water plants, seeds, grain, and acorns. They may also take some aquatic invertebrates and small fish. They prefer to nest in tree cavities near water, laying 9-12 eggs that are incubated by the female for around 30 days. The ducklings are able to fly after about 60 days. Outside of breeding season, mandarin ducks are highly gregarious and may form large flocks. Their flight is fast and direct.
Introductions outside of native range
The mandarin duck has been kept and bred in captivity since at least the 1600s, initially in China and Japan. More recently, mandarin ducks have been maintained by aviculturalists and waterfowl collections in Europe, North America, and elsewhere outside of its native range.
Beginning in the late 1800s, escapes and intentional releases from captivity led to the establishment of feral mandarin duck populations in various locations across the Northern Hemisphere. The most well-established non-native populations occur in the United Kingdom and Ireland, originating from captive releases beginning in the 18th century. Other notable populations have become established locally across parts of Northern Europe, Canada, and the United States.
Mandarin duck introductions in North America
In North America, non-native mandarin ducks likely first stemmed from escapees from aviculture. Sightings were occasionally reported across the continent throughout the 1900s. Over time, small local populations became established in areas where mandarin ducks found suitable habitat and the presence of other captive waterfowl species.
Notable mandarin duck populations in the United States include:
- New York City and Long Island, NY – Mandarin ducks are regularly observed in Central Park and elsewhere in the NYC metropolitan area. The population likely stems from escapees from zoos and waterfowl collections in the area. They are not yet known to be breeding in the wild in NYC.
- Western Oregon – A feral population became established in the 1990s, possibly from an escape from the Oregon Zoo in Portland. Mandarins occur along the Willamette River and have been documented nesting.
- Chesapeake Bay watershed – Sightings occur periodically in Maryland and Virginia, particularly during winter. There are a few records of mandarin ducks nesting in the wild in Maryland.
Other parts of the US with occasional mandarin duck sightings include Texas, Colorado, California, and Georgia. Canada hosts feral mandarin ducks in the provinces of British Columbia and Ontario. Overall, North American mandarin duck populations remain small and highly localized compared to the species’ native range.
Status of mandarin ducks in the United States
While mandarin ducks have settled and reproduced in parts of the US, most localized populations remain fairly small. The species has not expanded rapidly across North America, likely due to habitat limitations and mandarin ducks’ fairly low dispersal behavior. A few key factors about the status of mandarin ducks in the United States:
- The feral US population likely numbers in the low thousands of ducks at most.
- Reproduction in the wild has been documented in some locations, such as western Oregon, but breeding is sporadic.
- Many sightings still represent escaped captive birds rather than locally sustaining populations.
- They remain a non-native species and concerns exist about potential competition with native ducks.
- Harsher winters and lack of suitable cavities for nesting may limit population growth.
- No evidence points to mandarin ducks becoming invasive and displacing native species in the US.
So in summary – yes, there are feral mandarin ducks living in parts of the United States, but stable and large breeding populations have not become widely established across North America. The species occupies a limited niche outside of its native range and does not appear to be rapidly expanding its territory. Continued escapes from captivity supplement feral populations locally. Careful monitoring is warranted, but aggressive control measures have not been necessary to date.
Comparison to the wood duck
The native North American wood duck (Aix sponsa) occupies a similar ecological niche to the mandarin duck. Comparing the two species provides some useful context for assessing the potential establishment and impacts of mandarin ducks in the US.
Similarities
- Both species nest in tree cavities and live near wooded wetlands.
- They have predominantly herbivorous diets.
- Mandarin ducks and wood ducks are both highly ornamented waterfowl.
- Neither species undertakes long distance migrations.
Differences
- The wood duck is native to North America, while the mandarin duck is Eurasian.
- Wood ducks are significantly more abundant across their range than mandarin ducks are in Asia.
- The breeding range of the wood duck is much larger.
- Wood ducks are more adaptable to disturbed and human-altered wetlands.
- Mandarin ducks have more specific forest nesting requirements.
Potential impacts of mandarin ducks establishing in the US
Because mandarin ducks fill an ecological role similar to wood ducks, there is some concern they could compete with or displace native ducks if they became more widespread. However, there are also reasons why mandarin ducks may have limited negative impacts:
- Habitat limitations and nesting constraints likely restrict mandarin duck establishment.
- No evidence from Europe shows mandarin ducks outcompeting native ducks.
- The two species co-occur in parts of Russia without issue.
- Mandarin ducks are less adaptable to disturbed urban areas than wood ducks.
- Disease introduction from mandarins is a low risk.
- Food competition seems unlikely to be significant.
While the impacts are uncertain, the limited number and distribution of mandarin ducks in the US suggests major effects are unlikely. Avoiding further releases of captive mandarins may limit population growth. Wood ducks remain widespread and mandarin ducks do not appear to be displacing them. Continued monitoring is prudent, however.
Conclusion
In summary, small but established populations of feral mandarin ducks are present in parts of the United States as a result of escapes and releases from captivity. The largest populations occur in New York, Oregon, and Maryland. However, mandarin ducks have not expanded rapidly across North America and remain localized. While they may compete with native ducks like the wood duck, there is little evidence of significant negative impacts. The mandarin duck’s limited hardiness to urban areas and specific nesting requirements likely constrain it from becoming truly invasive. At current population sizes, the presence of the mandarin duck in the US seems unlikely to be cause for major management concern. Nonetheless, monitoring feral mandarin duck populations and limiting further releases makes sense going forward.