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Waddle into the World of the Chiloe Wigeon: Behavior Habitat and Survival

The Chiloe Wigeon, scientifically known as Mareca sibilatrix, is a species of duck native to the southern half of South America. Named after the Chiloe Island in Chile, where it was first discovered, this duck is known for its distinctiveness and charm.

In this article, we will discuss the identification, field identification, plumages, and molts of this magnificent bird.


The Chiloe Wigeon is a medium-sized duck, measuring approximately 45 to 55 centimeters in length, weighing about 700 grams. Males and females differ in their appearance, with the males having a striking white forehead, crown, and nape, while females have a darker brown color.

The males’ upperparts, neck, and breast are a beautiful chestnut brown color, blended with a grayish underpart. Moreover, males have a bright green patch on their wings, whereas females lack this feature.



Chiloe Wigeons are usually found in freshwater lakes, swamps, and nearby wetlands, which are often covered with vegetation. During winter, it’s not unusual to find them near the coastlines.

The males’ loud whistling wingbeat is also a unique characteristic of the species. Additionally, their calls are a series of whistles that resemble a Pekin duck.

Similar Species

Confusing the Chiloe Wigeon with other species such as the American Wigeon and the Eurasian Wigeon can happen, especially in non-breeding plumage. The American Wigeon is a close relation, and their males almost look alike; however, the green patch on the wing of the Chiloe Wigeon gives it the uniqueness it requires.

Conversely, the Eurasian Wigeon lacks the green color and has a more extensive pinkish bill.


The breeding male Chiloe Wigeon has the most colorful plumage. In contrast, non-breeding males and females are less distinctive in their looks.

During the breeding season, the male’s chestnut upperparts and bluish-gray underparts create a beautiful contrast. In contrast, non-breeding males and females are characterized by a less distinct pattern, with a mottled brown plumage, and lacking the bright green patch on the wing as seen in breeding males.


As with other waterfowl species, Chiloe Wigeon undergo a molt during summer, replacing their old feathers with new ones. Females usually have a more extended primary molt than males.

While the male’s bright green patch on the wing is still present in the post-breeding molt, its size can vary. In conclusion, the Chiloe Wigeon is a unique and exciting duck species found in the southern half of South America.

Its distinctive traits and distinctiveness make it an intriguing species to study and observe. Through this article, we hoped to provide a better understanding of this species’ identification, field identification, plumages, and molts.

Systematics History:

The Chiloe Wigeon was first described by French naturalist Louis Jean Pierre Vieillot in 1816, who initially named it Anas sibilatrix. Since then, there have been many revisions to its classification, from being classified as a member of the dabbling duck genus Anas to being placed into the genus Mareca.

Geographic Variation:

The Chiloe Wigeon is a widespread species with a distribution extended throughout southern South America, from Tierra del Fuego to central Chile, and may be found east of the Andes all the way to the Atlantic Ocean. While the Chiloe Wigeon is generally considered an endemic species, the species is known to overlap in distribution with American Wigeon during the non-breeding season, particularly in central Argentina.


There is only one recognized subspecies within the genus Mareca sibilatrix, the Andean race Mareca sibilatrix variegata. The Andean race, which is distributed broadly throughout the Andes and in arid regions to the northwest of the Andes in South America, is readily discernible from the typical race by its smaller size and generally darker plumage.

Related Species:

The Chiloe Wigeon is known as a close relative of the Northern Hemisphere’s American Wigeon. It was initially grouped with the genuine ducks of the genus Anas but was later placed in the genus Mareca of ducks.

Through various molecular studies, the status of the Chiloe Wigeon as a separate species has been unequivocally confirmed in recent years, and it is now widely considered as a monotypic genus. Historical Changes to Distribution:

The historical distribution range of the Chiloe Wigeon has undergone significant changes due to various factors such as habitat destruction and fragmentation, hunting, and global climate fluctuations.

In the last decade, the species’ range has extended northwards and expanded significantly, especially in Colombia. The species has also been introduced to other countries, such as New Zealand, where it displays an established feral population.

The indigenous mapuche people from the Chiloe Archipelago have traditionally hunted extensively for the Chiloe Wigeon. However, the birds’ population in Tierra del Fuego was significantly reduced by hunting until the 1960s, along with habitat fragmentation.

Nevertheless, conservation measures were implemented over the years, leading to the species’ recovery.

Climate change has also influenced the species distributional range.

In the southernmost parts of South America, territories near the coast have undergone alterations in the past owing to climate change. This has led to a significant change in species composition, with Chiloe Wigeons’ populations increasing in areas that previously lacked them as breeding birds.

The species’ ecological flexibility and ability to adapt to various habitat types have also allowed for the expansion and establishment of feral populations outside of its original range. Feral populations have been established in Argentina, as well as in Australia and New Zealand, likely due to escapees from avicultural breeding programs.

Recent surveys in New Zealand suggest that the birds are establishing themselves. Conclusion:

The Chiloe Wigeon is a fascinating species of duck native to southern South America.

From its systematics history, geographic variation, subspecies to related species, this article elaborates on their history, presence, and distribution and how they have been shaped by various forces. Furthermore, understanding the historical changes in the bird’s distribution can aid in conserving the species in its various geographical areas, particularly in responding to environmental modifications, enabling the better management of its extinction risk level.


The Chiloe Wigeon is a species of duck that inhabits a range of aquatic environments, including ponds, lakes, marshes, and lagoons. It prefers freshwater habitats such as rivers and streams but can also be found in brackish water.

The species is widely distributed, from below sea level to as high as 4000 meters in the Andes. It is primarily a resident species, staying in the same region throughout the year, relying on the availability of seasonal food sources.

The Chiloe Wigeon is well adapted to heavily vegetated wetland habitats, where it uses cover to forage, breed, and evade predators. These habitats provide excellent cover and a feeding source for the species, which primarily feeds on a diverse diet of aquatic vegetation, insects, and small invertebrates.

Movements and Migration:

The Chiloe Wigeon is primarily a resident bird that stays in one area throughout the year; however, some scattered migratory individuals and small groups may move towards northern breeding sites. The species extends through southern South America’s cold latitudes, making it the southernmost wigeon species in the world.

During the breeding season, Chiloe Wigeons pair up and remain in close proximity to one another, often forming pairs in other habitats outside regular breeding areas. The species is well adapted to cold, wet environments and can survive in these areas throughout the year.

During the winter months, the Chiloe Wigeon may move to areas with more open water, coastal shores, and estuaries. During the non-breeding season, some Chiloe Wigeons are known to migrate in groups, particularly from the Punta Arenas region to the north of the species’ range.

However, there is limited information regarding these movements. Studies have shown that some of the species’ populations undergo periodic fluctuations in relation to food availability and climate change.

For example, population fluctuations in Tierra del Fuego may be due to climate-induced vegetation changes and agricultural land use practices that have impacted traditional wintering grounds. Climate change has also had an impact on the species’ migratory behavior.

With rising temperatures due to climate change, the birds now alter their foraging habits and make use of new resources. In recent years, there have been notable changes in seasonal weather patterns and changes in the amount of rainfall, leading to a corresponding increase in the species’ range, including feral populations.


The Chiloe Wigeon is an intriguing species of bird that is well adapted to cold and wet environments. Understanding the bird’s habitat preferences and seasonal movements is crucial in managing and conserving the species’ various populations.

Through its successful adaptation and flexibility in utilizing seasonal food sources, cover, and various habitats, the Chiloe Wigeon has been able to survive in a range of wetland environments throughout southern South America. As climate conditions alter, the bird’s range and habitat preferences may also change.

Understanding how the species is impacted by these changes is critical for guiding conservation management strategies that include habitat conservation, monitoring migratory patterns, understanding population dynamics and their foraging and ecological roles in the ecosystems they inhabit. Furthermore, identifying and monitoring feral populations, preventing the spread of invasive species that could compete with the Chiloe Wigeon for resources, and understanding the bird’s migration behavior will further aid in developing and maintaining conservation measures to ensure the species’ survival.

Diet and Foraging:


The Chiloe Wigeon feeds by foraging on the surface of water or on the surrounding vegetation. It also feeds on aquatic insects, invertebrates, and vegetation.

The species has a habit of up-ending to feed and can often be seen in this posture, with its tail pointing upwards as it feeds on aquatic vegetation. This feeding habit is believed to contribute to the bird’s buoyancy, allowing it to move freely and hunt underwater without sinking.


The Chiloe Wigeon has a varied diet that changes across the bird’s range and changes with the seasons. The species’ diet comprises a mix of aquatic invertebrates, mollusks, insects, and a range of vegetation, including both submerged and floating species.

During winter, the Chiloe Wigeon moves to coastal and estuarine areas, where it feeds primarily on submerged seaweed. Some Chiloe Wigeons have also been observed feeding on land, particularly on agricultural land and pastures.

Metabolism and Temperature Regulation:

The Chiloe Wigeon, like other birds, has a high metabolism that is associated with the need to maintain core body temperature, especially in cold environments. The bird’s metabolic rate increases during cold weather conditions, allowing it to regulate its body temperature.

During times of food scarcity, the Chiloe Wigeon can reduce its metabolic rate to conserve energy. The Chiloe Wigeon, to help regulate its internal temperature, will also alter its position or change its location.

In particularly cold weather, it may huddle to retain warmth or seek shelter in vegetation to reduce heat loss. Glorioso Island is home to the southernmost breeding congregation of this species, where night temperatures regularly fall below freezing point.

Sounds and Vocal Behavior:


The Chiloe Wigeon is a relatively vocal species and has a loud whistle emitted on the wing-beat, which serves as an identification mark. It has a variable vocalization, from thin and high-pitched to deep and gravely, for males and females, respectively, and can utter a series of short, high-pitched whistles.

The male’s calls have a distinct series of whistles that sound like “whee whee whee whee” and are often heard when the birds are in flight. In contrast, females’ calls are softer and have a lower pitch.

During the breeding season, males also produce a more complex sound during courtship displays. In conclusion, the Chiloe Wigeon is a fascinating bird species with a unique diet and foraging behavior.

The bird’s varied diet allows it to survive in different environments across its range, and its feeding habits, including up-ending to feed, enable it to forage on both the surface and underwater. The bird’s metabolism and ability to regulate its internal temperature allow it to survive in cold environments, while its vocalization serves as an identification mark and forms part of its social behavior.

Overall, understanding the bird’s behavior, including its diet, foraging behavior, and vocalization, is essential in managing and conserving the species and ensuring its survival. Behavior:


The Chiloe Wigeon has a relatively slow and steady flight and spends a considerable amount of time swimming.

The bird’s swimming strategy involves paddling with its feet, which can occasionally be used as propulsion, and its wings are used for balance, changing direction, and increasing speed. The species can also dive to forage for food or to evade predators.

The bird’s legs are placed quite far back on its body, and this configuration facilitates swimming but makes the bird waddle awkwardly on land. Self Maintenance:

Chiloe Wigeons are relatively fastidious in their self-maintenance, often preening their feathers and shaking their wings to clear off any sand or debris.

They will also dive underwater to wash off any dirt and groom their feathers, ensuring that they remain waterproof and insulated. Agonistic and Sexual Behavior:

During breeding season, males become territorial, aggressively defending their chosen mate and preferred nesting site from other males.

These territorial birds often posture and vocalize as a display of dominance over other males. The Chiloe Wigeon is also known for its use of ritualized agonistic behavior and displays during territorial disputes or other conflicts.

Sexual Behavior:

The Chiloe Wigeon is monogamous during the breeding season, seeking out the same mate year after year, and mating typically occurs on the water. During courtship, males will perform a series of displays, including preening and wing shaking, to attract the female.

In response, females may vocalize and paddle away, sometimes followed by the male, in a courtship chase. After successful courtship, the nest is constructed by the female, who lines the pit with a range of materials, including bark, grass, and feathers.


The breeding season of the Chiloe Wigeon occurs during the southern hemisphere’s late winter and early spring, typically from August to November, but it can vary depending on the region. During this time, males will become aggressive towards other males, starting to display their territorial behavior, in which they become highly territorial over their chosen mate and preferred nesting site.

The species is monogamous, and stably occupied pairs are predominantly harbored in the extended coastal plain and the foothill zone. Females are responsible for nest-building, typically constructing their nest on the ground near the water’s edge, hidden in vegetation or against some other structure.

A clutch usually consists of four to six eggs, which are incubated by the female for about 24 to 26 days. Upon hatching, the chicks are precocial, meaning they are born with downy feathers and open eyes, allowing them to feed themselves within a few hours of hatching.

The parents then guide the chicks to water, where they can learn to swim and forage for food. Demography and Populations:

The Chiloe Wigeon population is generally considered to be stable.

However, data on the species’ population is limited, and some populations are known to undergo periodic fluctuations, particularly in response to environmental changes. Tierra del Fuego’s population was heavily impacted by hunting and habitat fragmentation until the 1960s, leading to a decline in the bird’s population.

However, strict conservation measures and the bird’s resilience have enabled its populations to recover. In recent years, changes in annual weather patterns and the availability of resources within the species’ range have also impacted the bird’s population.

As interactions between habitat fragmentation and population dynamics pass through subtle predator-prey cycles, it becomes evident that maintaining and managing these regions are crucial in the preservation of species. The establishment of feral populations outside the species’ range also poses a risk of disease transmission and genetic contamination, impacting the genetic diversity of the species.

In conclusion, the Chiloe Wigeon is a fascinating bird with unique behaviors, including its locomotion, vocalization, and breeding patterns. The bird’s behavior during the breeding season is characterized by agonistic and sexual behavior, with males defending their chosen mate and preferred nesting site from other males.

The species is monogamous and constructs new nests each year. Changes in annual weather patterns and resource availability can impact the bird’s population.

Understanding these behaviors and population dynamics is crucial for conservation management strategies that preserve the species and contribute to its long-term survival. Overall, this article has detailed the unique characteristics of the Chiloe Wigeon, including its systematics history, habitat preference, movements, behavior

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