This vulnerable bird has given us some of the world's most luxurious products. Few now remain
"Over the past ten years, common eiders have started breeding almost two weeks later than they used to," says a researcher.
A little girl sits beside piles of eiderdown at a farm in Northern Norway, photographed by zoologist Robert Collett (1842–1913).(Photo: Robert Collett / CC BY-NC-ND 3.0)
The male common eider is easy to recognise. It is white and black, with a distinctive green patch on the back of its neck.
The common eider is a large sea duck that has played an important role in the lives of coastal communities throughout Norway. But its numbers are declining.
Common eider populations are shrinking across nearly the entire country. The Norwegian Institute for Nature Research (NINA) monitors many different eider populations along the coast and carries out regular surveys to track their numbers.
"There has been a decline along almost the entire Norwegian coast for quite a number of years now," senior researcher Sveinn Are Hanssen tells Science Norway.
Many male common eiders outside a small rocky island.(Photo: Rolv Lundheim / CC BY 4.0)
Over the past few decades, common eider numbers have fallen dramatically across most of Norway. Between 1986 and 2013, the population declined by as much as 50 per cent in the region stretching from northwestern Norway up to Nordland, according to the Norwegian Biodiversity Information Centre.
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This is one of the reasons why the common eider population was classified as vulnerable in 2021. It had previously been assessed as being of least concern, according to the Red List assessment (link in Norwegian).
Associated with luxury
Hanssen is one of the researchers monitoring common eiders in Northern Norway, where these birds have played a particularly special role.
There are several reasons why there are fewer common eiders than before. One of them is closely connected to human activity. As settlement patterns and traditional ways of life along Norway's coast have changed, common eiders have lost an important source of protection. For generations, coastal communities took great care to safeguard these valuable birds.
Eiderdown is in a class of its own. When female common eiders lay their eggs, they line their nests with soft feathers known as eiderdown. It is considered the finest down available.
Duvets and pillows filled with eiderdown sell for tens of thousands of Norwegian kroner. If you want to buy an eiderdown duvet suitable for a double bed, you can easily expect to pay NOK 80,000–100,000 (USD 8,400–10,500).
Recently, duvet manufacturer Lånan AS announced that it was shutting down because of declining eider populations. With too few birds remaining, the company can no longer collect enough eiderdown to produce its luxury duvets, according to the Norwegian Broadcasting Corporation NRK.
But collecting down used to be far more common practice.
“People looked after the common eiders that lived on small islands and rocky islets,” says researcher Sveinn Are Hanssen.
For centuries, coastal residents collected and sold down gathered from eider nests.
In return, they made sure the birds had safe and suitable places to breed. Without people looking after them, the birds are far more vulnerable.
An extremely shy bird
The birds blend into the landscape and hide their nests in crevices and beneath bushes.
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They are very shy and avoid nesting on the mainland to stay hidden from foxes and other land-dwelling predators, Hanssen explains.
This is one of the ways researchers count the number of breeding common eiders. They try to locate nests on small islands and then count them.
Another method is to count the males gathered around a known breeding islet. Male common eiders keep watch over the females that lay eggs.
A common eider nest containing eggs. Here you can see the extremely soft and insulating eiderdown.(Photo: Shutterstock / NTB)
Counting the males gives researchers an indication of how many females may be hidden away in their nests, tending to their eggs, Hanssen says.
People once protected the eiders
For hundreds of years, people living along the coast helped provide safe breeding grounds for common eiders, particularly in Northern Norway.
"People lived on small islands and rocky islets, looking after the eiders and driving away crows, gulls, and otters," says Hanssen. "But since the 1950s and 1960s, people have gradually moved away from these islands and islets."
As a result, fewer and fewer people now live in the places where common eiders breed.
Mink pose a serious threat
Another major threat to common eiders comes from mink, which were introduced to Norway through the fur-farming industry.
Animals that escaped from fur farms established populations in the wild. They eat seabird eggs.
"Mink are very good swimmers, so they can reach small islands and rocky islets. With nobody living there anymore to protect the birds, the mink are free to wreak havoc," the researcher says.
A mink on the hunt. These animals can now be found throughout Norway.(Photo: Rolv Lundheim / CC BY 4.0)
Hanssen believes that the Norwegian Nature Inspectorate has gained better control over the mink population over the past ten years.
The Norwegian Nature Inspectorate has been responsible for killing mink in coastal areas since 2011, according to this research article from 2025 (link in Norwegian).
It is also possible to eradicate mink in specific areas, according to the study.
"But we can't simply declare that the mink problem has been solved and that we can now relax. This requires continuous effort. Every winter, we need to capture as many mink as possible along the coast," says Hanssen.
Thousands of nests
The extensive down-harvesting site at Store Tamsøya in Northern Norway could produce up to 250 kilograms of down per year.
According to the reference work, around 60–70 nests are needed to collect one kilogram of down. That means up to 18,000 nests to collect 250 kilograms.
These places are known as egg- and down-harvesting sites, where people collected both eggs and down from seabirds.
Some of the boxes containing down from the Oseberg Viking burial mound, during repackaging in 2009.(Photo: Marianne Vedeler)
The collection of eggs and down is regulated, with harvesting rights reserved for landowners.
Down has been used by humans for thousands of years. Archaeologists have discovered it in prestigious burial sites dating from the Viking Age and the centuries preceding it.
These are just some of the reasons why common eiders are struggling more than before.
Another problem is their diet. Climate change is making blue mussels, one of the eider's preferred food sources, increasingly difficult to find, according to Hanssen.
Having access to the right food at the right time is critically important for the eider's survival. The female has to build up her fat reserves before incubating her eggs.
A female common eider incubating her eggs. This photograph was taken in Svalbard.(Photo: Angela N Perryman / Shutterstock / NTB)
Go without food during incubation
"They have to eat a great deal during March and April before laying their eggs," says Hanssen.
Only the female eiders incubate the eggs, and during this period, which can last up to 30 days, they do not eat.
"During that time, she essentially starves. She loses 40 per cent of her body weight," he says.
To cope with this strain, the common eider must have eaten enough beforehand, and this is becoming increasingly difficult.
Hanssen explains that both the colony he works with and other colonies in Northern Norway show the same trend: eiders are taking longer and longer to build up sufficient fat reserves.
"Over the past ten years, eiders have started breeding almost two weeks later than they used to," the researcher says.
Eider ducks are faring better in the Oslofjord
One of the few places where common eiders appear to be doing well is in the inner Oslofjord.
After an initial period of population growth, their numbers have now stabilised. These birds inhabit the waters stretching from the Drøbak Strait northwards towards Oslo.
Hanssen explains that common eiders are a relatively new species in the inner Oslofjord. They began breeding there in the early 1980s.
"The birds are clearly doing well, which is interesting given all the disturbance caused by small boats," he says.
In June, female eiders swim around with their ducklings. This is a vulnerable period, coinciding with the height of the recreational boating season.
If you spot eiders from your boat at that time, it may be wise to take extra care. The young birds take quite a while to learn to fly and escape danger.
"They swim around with their young for several weeks before the ducklings learn to fly," the researcher says.
