Cherished and respected by mankind for centuries, supremely adapted for life in cold northern waters and the subject of some of the very earliest conservation measures in the world, the Common Eider is a remarkable bird but more people know about its feathers than the bird itself. So treasured is the Eiderdown, and so labour-intensive is the annual harvest of it, depending on the size of your bed, an Eiderdown quilt can sell for as much as €15,000 in some Dublin outlets.

That its feathers are far more famous than the bird that bears them is something of a pity: it deserves to be better known for its own sake. It is tough, it is beautiful, and it sounds like nothing else in all of nature.

In this special Mooney Goes Wild programme, Derek snuggles up with the Common Eider.

(Photo courtesy of Gudrun Gauksdottir, Chairperson of the Association of Eider Farmers)

Eiders are perfectly adapted for life in cold seawater, and they nest along the coastline of northern parts of North America, eastern Asia and Europe, including in Ireland. The male Eider – the drake – is a very striking bird indeed. His body is largely white, with a contrasting black belly, sides and rear end, and with a delicate salmon-pink wash on his chest. He has a black cap on top of his head, along with a very sloped, yellowish "Roman nose"-style beak. Most striking of all, though, are the patches of pastel lime-green on the sides and rear of his neck, more on which anon.

The female, as with most female ducks, is altogether more drab in appearance, being a mottled brown colour all over. Her brown feathers provide vital camouflage when she is incubating her eggs, helping her to blend in with her surroundings and avoid detection by predators. The male Eider, as is the case with most duck species, plays no role in incubation or childcare, and so can afford to look as flashy and conspicuous as he likes.

(Photo - Derek Mooney)

Eiders live for 20 to 25 years and return to the same nesting grounds year after year. It is the female Eider alone who produces the famed eiderdown. Each adult female only produces approximately 16 g of it each year: roughly half an ounce. When building her nest, she plucks this pre-loosened down from her breast and uses it to create a soft and extremely well-insulated lining for her precious eggs.

It's not just her eggs that are precious. Eiderdown commands such high prices because it is so scarce a commodity. Eiders can't be farmed or raised in captivity to ensure a supply of their soft down feathers, so all of the world’s eiderdown must come from wild sources. It is said that each year, more Rolls Royce cars are produced than eiderdown quilts!

Crucially, no Eiders are actually harmed in the production and commercial harvesting of eiderdown. For centuries, communities in northern Europe and North America have known that it is vital to safeguard the female Eiders and their nests, so that the birds will return again to nest in subsequent years, and to ensure that the population of these remarkable ducks remains strong and healthy. The Eiders benefit from the protection, while the humans benefit from a perpetual supply of the finest natural insulation material in the world: the ideal symbiotic relationship, and a perfect example of sustainable natural harvesting.

Much of what has been traditionally called "eiderdown" in Ireland has been anything but. The word almost became a generic term for any feather-stuffed quilt, but not all feathers are created equal. The vast majority of the so-called "eiderdowns" in Irish homes are actually stuffed with much cheaper domestic goose or Mallard down, a by-product of the massive Chinese poultry farming industry. These down feathers do themselves provide excellent insulation, and at a much more affordable price . . . but true eiderdown, from the breast of the female Eider duck, is more than twice as effective an insulator, and far lighter to boot. Unlike other down feathers, its filaments cling together like Velcro, meaning that it is much more efficient at trapping and retaining warm air.

(Photo courtesy of Gudrun Gauksdottir, Chairperson of the Association of Eider Farmers)

The scarcity of the product and its incomparable insulating abilities have meant that the laws of supply and demand have long controlled the eiderdown market. For centuries, it was considered the preserve of the rich and powerful, and became a status symbol and a hallmark of supreme luxury. For example, the Titanic, which sank in 1912, had 800 eiderdown duvets onboard, to cater for the needs of its first-class passengers.

As a species, the Eider is doing fairly well. They tend to live in quite remote areas, away from the human pressures that now afflict so many other waterbirds. Also, because they dive deep to feed on bottom-dwelling molluscs and crustaceans, as opposed to surface-dwelling fish, they don’t suffer to such a degree as other seabirds from the impacts that rampant commercial overfishing and pollution have had on marine ecosystems.

(Photo courtesy of Gudrun Gauksdottir, Chairperson of the Association of Eider Farmers)

A particularly famous colony of Eiders lives on the Farne Islands in Northumberland, England. These birds were the subject of one of the first ever bird protection laws, established by Saint Cuthbert in the year 676. He even encouraged the ducks to nest inside his church, around the altar, and placed them under his personal protection. It must have worked: around 1,000 pairs still nest in St. Cuthbert’s colony today, and locals still call them "Cuddy’s Ducks", "Cuddy" being a shortened version of "Cuthbert".

(Erla Fridricksdottir, CEO of family run firm KING EIDER - Photo - Derek Mooney)

With or without saintly protection, female Eiders are excellent, attentive mothers. Not alone do they pluck their own breast feathers to ensure a soft, warm nest lining for their eggs and chicks, they perform 100% of the egg incubation duties. Incubation of the 4 to 6 eggs lasts for 25 for 26 days, and so attentive is the female that she won’t eat at all for the entire duration.

She also has a pretty special trick up her sleeve. If a predator, such as a fox, threatens the nest and chases the female away, as she flies up to escape, she deliberately defecates all over her eggs. It is thought that this is probably an attempt to make the eggs less palatable to the predator, in the hope that it will decide to give them a miss.

( Niall Hatch - Development Officer at BirdWatch Ireland)

After hatching, female Eiders also go to great lengths to protect their young ducklings as they grow. Like other duck species, Eider chicks are extremely advanced – or precocious, as an ornithologist might say – when they hatch out of their eggs. They can run and swim immediately, and their mother quickly leads them away from the nest and out to the relative safety of the sea.

Eiders are colonial nesters, breeding in groups which range in size from a couple of dozen to over 15,000 birds, and the females help each other with the child-rearing duties. Remarkably, they operate a crèche system: while most of the mothers journey far out to deeper waters in order to feed, some stay behind and look after the floating rafts of fluffy youngsters – up to 150 ducklings each. Think of it as sort of a duck day-care facility.

Around 100 pairs of Eider breed annually in Ireland, with the coasts of Sligo, Donegal and Antrim being particular strongholds. In winter, numbers swell as migrants from Scotland and Scandinavia join our resident flocks to feed, and the Eider could be described as being locally common. The small size of our breeding population makes the species somewhat vulnerable, however.

The Bird Atlas 2007-2011, spanning Britain, Ireland, the Isle of Man and the Channel Islands, was a landmark collaboration between staff and volunteers of BirdWatch Ireland, the British Trust for Ornithology and the Scottish Ornithologists’ Club. One of its key discoveries was that the breeding range of the Eider in these islands was gradually expanding southwards, and that the species was colonising new areas. For example, once a rare sight off the coast of Co. Dublin, previously considered to be too far south for the species, it is now regularly seen off the town of Skerries.