Widgeons, also known as Eurasian widgeons or just wigeons, are dabbling ducks that belong to the genus Mareca. There are three extant species of widgeons: the Eurasian widgeon (Mareca penelope), the American widgeon (Mareca americana), and the Chiloé widgeon (Mareca sibilatrix). Of these three species, the Eurasian widgeon has the largest range and is the most numerous, while the Chiloé widgeon has the smallest range and is quite rare.
Overview of widgeons
Widgeons are medium-sized ducks that frequent shallow wetlands and marshes. The males have distinctive plumage patterns during the breeding season, with white patches on their wings that are visible during flight. Outside of the breeding season, the male’s plumage becomes drabber and more female-like. Widgeons feed primarily by dabbling or upending in shallow water to reach submerged vegetation and invertebrates. They are social ducks and often gather in large flocks during migration and winter.
Widgeons belong to the diverse family Anatidae, which includes ducks, geese, and swans. There are around 140 species in this family worldwide. Most species in the Anatidae family have wide distributions across North America, Europe, Asia, and Africa. However, habitat loss and overhunting have caused population declines in many waterfowl species, including some species of widgeons. Conservation efforts and hunting regulations have helped some populations recover in recent decades.
Range and population of the Eurasian widgeon
The Eurasian widgeon has an extremely large range across Europe, Asia, and parts of North Africa. Its breeding range extends across much of northern Europe and Asia. Some key breeding areas include Iceland, the United Kingdom, Netherlands, Germany, Poland, and regions across Russia and Siberia. During winter, Eurasian wigeons migrate south to regions like the Mediterranean, northern Africa, the Middle East, India, China, and Japan.
Thanks to its vast range, the Eurasian widgeon is evaluated as Least Concern on the IUCN Red List of Threatened Species. Its population is estimated to be between 2.8 to 3.2 million individuals. Eurasian widgeon numbers dropped in the mid-20th century due to hunting pressure and wetland loss, but have rebounded more recently. For example, its population in the United Kingdom crashed from 100,000 to 4,000 between 1953 and 1983. But conservation measures allowed UK numbers to recover to around 22,000 by the mid-2000s.
Range and population status of the American widgeon
The American widgeon lives across North America and is migratory, breeding in Alaska, Canada, and the northern United States before migrating south to winter along the southern United States, Mexico, Central America, and the Caribbean. Its global population is estimated at around 3.5 million. Its numbers declined in the late 19th and early 20th centuries due to hunting and wetland drainage, but recovered to some extent during the 1900s after hunting regulations were introduced.
The American widgeon’s population remains below its historical numbers but the species is still very abundant and widespread, leading to a conservation status of Least Concern. However, local populations in parts of the western United States have declined more sharply in recent decades due to factors like drought, water diversion projects, and habitat loss. Conservation efforts for wetlands in the American west could help bolster populations of species like the American widgeon.
Range, population, and conservation status of the Chiloé widgeon
The rarest and most threatened species of widgeon is the Chiloé widgeon. This species lives only on a small island off the coast of Chile called Chiloé Island. It USED to occur more widely along the west coast of southern South America. But habitat destruction and hunting caused it to disappear across most of its former range. By the 1970s, its entire population was restricted to Chiloé Island.
Due to its tiny and shrinking range, the Chiloé widgeon is classified as Critically Endangered by the IUCN. Its total population likely numbers fewer than 500 total adult birds. Because its population is so small and localized to one island, it faces threats from random events like oil spills, introduction of invasive predators like rats, or outbreaks of avian disease. Aggressive conservation action will be needed to prevent extinction of the Chiloé widgeon and help expand its range and population size again.
Comparison of widgeon population sizes
The Eurasian widgeon is clearly the most abundant and widespread species of widgeon, followed by the American widgeon. The Chiloé widgeon is extremely rare. To put their population sizes in perspective:
Species | Population Estimate |
---|---|
Eurasian widgeon | 2.8 to 3.2 million |
American widgeon | 3.5 million |
Chiloé widgeon | Fewer than 500 adults |
As these numbers show, the Chiloé widgeon is many thousands of times rarer than the abundant Eurasian and American wigeon species. The scarcity of the Chiloé widgeon is directly tied to its tiny and shrinking geographic range.
Geographic breeding range size differences
The widgeon species also differ tremendously in terms of the size of their geographic breeding ranges. This is visualized in the table below:
Species | Breeding Range Size |
---|---|
Eurasian widgeon | 9,760,000 square km |
American widgeon | 7,160,000 square km |
Chiloé widgeon | 3,000 square km |
The Eurasian widgeon breeds across a vast swath of Europe and Asia, giving it the largest range size. The American widgeon’s breeding range across Alaska, Canada, and the northern US is only slightly smaller. In stark contrast, the tiny island of Chiloé Island constitutes almost the entire range of the Chiloé widgeon.
Reasons for the rarity of the Chiloé widgeon
Understanding why the Chiloé widgeon became so rare while other widgeon species remain relatively abundant comes down to a few key factors:
Extensive habitat destruction
Wetland drainage and degradation led to the disappearance of Chiloé widgeons across nearly all its former range. For example, it was once common in central Chile but declined due to agriculture and pollution. The Chiloé widgeons became confined to one small island that still maintains suitable habitat.
Overhunting
Early accounts described the Chiloé widgeon as abundant and easy prey for hunters. Unregulated overhunting during the 19th century was a major cause of its initial decline.
Narrow habitat requirements
Chiloé widgeons depend on estuaries with dense vegetation and freshwater influence. As coastal wetland habitats disappeared, the ducks could not easily move inland or adapt to altered habitat like other more generalized duck species.
Small founding population
Genetic diversity may have been lost when only a small population on Chiloé Island remained. Being restricted to a small island also makes the widgeons vulnerable to random threats and inbreeding.
Lack of conservation measures
Legal hunting protection and habitat conservation came too late to save Chiloé widgeons on the mainland. Ongoing efforts on Chiloé Island will hopefully prevent their complete extinction.
Conclusion
In summary, the Chiloé widgeon is an extremely rare bird with an estimated population of fewer than 500 adults confined to a single small island. In contrast, the Eurasian and American wigeons number in the millions across vast continental ranges. Overhunting and extensive wetland destruction caused Chiloé widgeon populations to collapse to the point where the species teeters on the brink of extinction. Aggressive habitat protection and management on Chiloé Island is needed to preserve this unique and critically endangered duck.