- 1 Sea Eagles
- 2 From Totem to Target: sea eagle distribution and decline
- 3 Return of a Native: reintroduction
- 4 Sea Eagles and the law
- 5 The Future
- 6 How can I help the Sea Eagle Project?
- 7 The Sea Eagle Project Team
- 8 Further Reading
The sight of a golden eagle soaring effortlessly above a high crag or along the side of a glen gives an added thrill to a day on the Scottish mountains. However it is now becoming much commoner to see Scotland’s other eagle – the sea eagle – specially along the west coast or the Hebrides.
The white-tailed eagle (Haliaeetus albicilla) or sea eagle was driven to extinction in Britain earlier this century. Now, thanks to a reintroduction programme run jointly by Scottish Natural Heritage and the Royal Society for the Protection of Birds, the sea eagle has returned to some of its former haunts.
The sea eagle is the fourth largest eagle in the world, and is our largest bird of prey, with a wingspan of nearly two and a half metres. By comparison, the golden eagle’s wingspan rarely exceeds two metres. The mature sea eagle has a greyish brown plumage with a pale head, reminiscent of its famous close relative, the bald eagle, national symbol of the USA. One striking feature is its yellow eye from which it gains a poetic Gaelic name Iolairesuilnagreine ‘the eagle with the sunlit eye’. Its beak and talons are also bright yellow.
The sea eagle only gains its characteristic white tail as becomes an adult. In flight, it appears rather like a huge vulture, with typically ponderous movements. When it soars its wings are held out flat and the tips often droop slightly.
As its name suggests, the sea eagle usually nests around coasts, but it in some parts of its range it may also be found near lakes and rivers further inland. The nest, or eyrie, is constructed of large sticks and branches. The eyrie must offer a clear view of the surroundings and provide easy access for the eagles themselves, but at the same time provide shelter and protection from predators which may steal their eggs or chicks.
Sea eagles sometimes begin displaying in October or November, but this becomes most intense in early spring. During courtship, the pair can perform daring aerodynamic feats, such as grappling talons in a mid-air cartwheel. They spend much of their time together, often soaring side by side or perched together on their eyrie. Their flight displays end quite abruptly once the eggs are produced. The two or three white eggs are laid in early spring and incubation, by both sexes, lasts 38 days. It is not uncommon for two chicks to survive amicably in the same nest. This is in contrast with the golden eagle, where the larger chick often deprives the younger sibling of food and only the largest may survive.
The sea eagle has a very varied diet. It feeds on fish, rabbits and hares, and a range of birds, including eiders, shags and auks. In the past, Shetlanders attributed the bird’s fishing ability to the supernatural. They believed that as soon as an eagle appeared fish would swim to the surface and offer themselves belly-up as a gesture of submission. In actual fact sea eagles are are quick to spot spent salmon on the spawing grounds, or take disabled fish forced up to the surface in deep tidal streams. Shetland fishermen also believed that smearing their own baits with sea eagle fat would improve their catches. Unlike the osprey which soars high above the water searching for prey and plunges in an awe-inspiring dive, the sea eagle tends to glide a few metres above the water before it descends to snatch the unsuspecting fish from the water with barely a splash. Although sea eagles are well able to catch live prey, they will often steal food from other predators such as otters, or follow fishing vessels in search of discarded scraps Sea eagles are also scavengers of carrion, particularly in the winter months.
From Totem to Target: sea eagle distribution and decline
Following the retreat of the glaciers at the end of the last Ice Age, about 10,000 years ago, sea eagles became established at sites from Greenland through Eurasia to Japan. However, persecution, loss of habitat and, more recently, pollution have led to a great decline in the numbers of sea eagles across the whole of their range. Although they were lost entirely from several countries, including Britain, they are making an encouraging comeback in some places. Norway has always been a stronghold with over 1,500 pairs.
Sea eagles were once a familiar sight throughout Britain. Their presence has been recorded in ancient art and local folklore . In Orkney, prehistoric peoples may have treated the sea eagle as totemic symbol, regarding it with superstitious respect. Remains Bones of the birds have been found buried together with human remains. This belief may have persisted into the Iron Age for the eagle can be seen in several Pictish carvings. , It also features in Anglo-Saxon poetry where a mention in The Seafarer is thought to refer to the Bass Rock.
During the Dark Ages the sea eagle was firmly established around Britain. However, as the ancient woodlands were felled and wetlands were drained to make way for farms, the area of land suitable for sea eagles declined. Remnant populations then became vulnerable to direct persecution. Predators and so-called vermin could no longer be tolerated on these new farmlands so laws were passed to encourage their destruction. By the end of the eighteenth century only a handful of sea eagles were left in England. A pair of sea eagles nesting on the Isle of Man in 1818 were the amongst the last to be recorded south of the border.
The destruction of habitat was much less severe in Scotland and Ireland and even into the nineteenth century sea eagles were still quite plentiful in more remote areas. Here persecution was the greatest threat. Generous bounties were offered for the birds in Orkney and Shetland for example, up to five shillings per head.
In areas where the eyries were relatively accessible, such as Galloway and Orkney, the birds were driven rapidly towards extinction. In more remote areas the number of breeding birds was not affected until the 1840s when a more rapid decline began. By 1900, only a handful of pairs remained.
This final decline demise was precipitated by the spread of sheep farming in the Western Highlands. Most of the local human population were dispersed to the very coastal areas favoured by sea eagles. Shepherds used poisoned baits and improved firearms to devastating effect. The Victorian passion for taxidermy and egg collecting increased as the birds became rarer and contributed to their final demise. The last known breeding attempt by indigenous sea eagles was on Skye in 1916. Two years later, the only surviving British sea eagle, an ageing albino female, was shot at her lonely outpost in Shetland. It was to be almost 70 years before sea eagles once again bred in Scotland.
Return of a Native: reintroduction
Despite being protected by law in most countries, sea eagles continued to suffer from persecution and the loss of their habitat. But after the middle of the last century, a new threat became apparent – from toxic chemicals such as organochlorine pesticides (DDT, DDE, dieldrin etc) and, later, from industrial pollutants such as polychlorinated biphenyls (PCBs) and heavy metals. This menace became most prevalent in parts of the Baltic and in Eastern Europe, where sea eagles were once common and soon suffered extensively. These persistent chemicals became concentrated in plant and animal tissue as they progressed up the food chain leading to breeding failures in the topmost predators such as eagles. Some birds even died from lethal dosages.
Various countries instigated desperate conservation measures, such as feeding clean food and captive breeding programmes while, at the same time, they also strived to ban the problem chemicals. Sea eagles had become scarce in many areas while Norway, with low levels of industry and pollution, managed to retain healthy populations. It was obvious that northwest Scotland offered similar opportunities if only sea eagles could re-establish. While the migratory osprey had returned naturally, it seemed unlikely that the more sedentary osprey would ever recolonise without human assistance.
How is reintroduction carried out?
In 1959 and 1968 attempts were made to reintroduce the sea eagle to Scotland but they did not involve sufficient numbers of birds, nor did they continue long enough to guarantee success. So in 1975, the Nature Conservancy Council (now called Scottish Natural Heritage) instigated a longer term reintroduction project. This was based on the Isle of Rum, a mountainous National Nature Reserve in the Inner Hebrides, where sea eagles had bred until 1907. It was also within sight of the last breeding pair in Skye.
Over the next ten years to 1985, a total of 82 eaglets (39 males and 43 females) were imported, under special licence, from nests in northern Norway where the sea eagle population was still expanding. Since the sea eagle often rears twins only one chick was taken from each nest and, such was the density of breeding pairs that different nests could be visited each time.
With generous assistance from RAF 120 Squadron, the eaglets – nearly fledged – were transported swiftly and safely to Kinloss in Scotland, and from there to the Isle of Rum. Installed in roomy cages on a remote shore the chicks were fed a natural diet of fish, birds and mammals, while they completed a statutory five weeks in quarantine. Once they were released food dumps were maintained nearby to supplement the birds’ diet and while they perfected their hunting skills. Even without parental example the young eagles became fully independent over the next few months and soon ranged further afield
Breeding success is achieved
Sea eagles take about five years to mature, so it was several years before the youngsters released on Rum began to form breeding pairs. The first eggs were laid in 1983, but failed to hatch, as did two clutches in 1984. However, in 1985 a pair of Rum birds now established on the nearby island of Mull, successfully reared the first wild sea eagle chick to be fledged in Britain for over 70 years. Progress was slow at first (with only half a dozen young from 8 or so pairs). So between 1993 and 1998 a further 58 Norwegian eaglets were set free, this time in Wester Ross. Momentum gathered and by the twenty fifth anniversary of the start of the project a dozen youngsters were reared from 22 pairs, including the hundredth chick to be fledged in the wild. By 2003 just over 30 pairs were established and a record 26 eaglets took to the wing. A further 19 followed in 2004.
Sea Eagles and the law
In common with all other birds of prey in Britain, sea Eagles are fully protected under the Wildlife and Countryside Act 1981. It is illegal to shoot, poison or otherwise kill sea eagles, to disturb them at the nest or to take eggs or young. Under the new Nature Conservation Act it is now illegal to disturb their nests and heavy fines, or even imprisonment, may be imposed for harming eagles or their eggs. .
SNH and RSPB staff are constantly watchful for any possible persecution of sea eagles. Sea eagle nest sites are kept under close surveillance by RSPB staff to ensure that the birds can breed without disturbance. However, as sea eagles readily scavenge on carrion, they are vulnerable to illegally laid poison baits. Several sea eagles, including at least two breeding adults, are known to have died from eating such baits and efforts continue to be made to reduce the risk of future casualties. (See the SNH booklet ‘Scotland’s Wildlife: the Law and You’.
Thanks to the phased reintroduction programme, sea eagles are once again breeding in Scotland. However, the current population is small and still vulnerable. Sea eagles are slow to mature and pairs often make several breeding attempts before successfully rearing chicks.
The RSPB are heavily involved in monitoring the population while research is being carried out to increase our understanding of the sea eagle’s breeding biology and habitat requirements in Scotland, and any impact they may have upon lambs. Although illegal poisoning still occurs, attitudes have changed markedly and the eagles have become quite a tourist attraction. A small public viewing hide is being operated on Mull by the islanders, in partnership with SNH, RSPB and the Forestry Commission, while CCTV cameras are operating at another nest in Skye, and can be viewed at the Aros Centre, near Portree.
We cannot expect all of the released birds or wild bred young to survive and some 10% or so have thus far been found dead, mostly inexperienced juveniles. Sadly a few had been poisoned, including two breeding adults. Together this pair had already fledged three young and in 2003 they left behind two little orphans. Attempts were made to foster the tiny chicks into other sea eagle nests and eventually one was to fledge successfully with its new parents. The poisoned territory has yet to be re-occupied.
But survival is encouragingly high, and at least as good as the healthy Norwegian population, so were are confident that the Scottish sea eagles are estabishing a self-sustaining population in the wild. It remains however for them to be able to spread to the east coast, north to Orkney and Shetland and south into England, Wales and Ireland. But even today few can deny that white-tailed sea eagles have made a welcome and dramatic return to its old haunts in the West of Scotland.
How can I help the Sea Eagle Project?
It is not uncommon now for visitors to the west of Scotland and the Hebrides to catch sight of a sea eagle. They are bigger, noisier and less shy than golden eagles and a popular analogy is that they resemble a ‘flying barn door’! All sightings are useful in tracking dispersal, survival and individual life histories. The more details you can provide the more valuable your record. Look out for any coloured tags on the wings, and try to read the letter, number or symbol which will reveal which individual it is. Remember to include you name and address so we may contact you to confirm details.
Please send all records to
RSPB, Etive House, Beechwood Park, Inverness IV2 3BW Tel 01463 715000
The Sea Eagle Project Team
The sea eagle reintroduction is overseen by a Project Team who co-ordinate efforts to monitor and protect the eagles as they re-establish a breeding population in Scotland. The Team is chaired alternately by SNH and RSPB and is made up of representatives from Scottish Natural Heritage, the Royal Society for the Protection of Birds, the Joint Nature Conservation Committee and the Centre for Ecology and Hydrology. You can contact the Sea Eagle Project Team care of: Species Group, Scottish Natural Heritage, 2 Anderson Place, Edinburgh EH6 5NP. Tel 0131 447 4784, or at SNH’s new headquarters in Inverness.
The Wildlife and Countryside Act 1981 has made it illegal to shoot, poison or otherwise kill sea eagles, to disturb them at the nest or to take their eggs.
Bainbridge, I.P., R.J. Evans, R.A. Broad, C.H. Crooke, K. Duffy, R.E. Green, J.A. Love and G.P. Mudge. 2003. Re-introduction of White-tailed Eagles (Haliaeetus albicilla) to Scotland. Birds of Prey in a Changing Environment. (eds. D.B.A. Thompson, S.M. Redpath, A.H. Fielding, M. Marquiss and C.A. Galbraith) pp. 393-406. HMSO, Edinburgh.
Evans, R.J., R.A. Broad, K. Dufy, A.M. Maclennan, I.P. Bainbridge and G.P. Mudge. 2003. Re-establishment of a breeding population of white-tailed eagles in Scotland. Sea Eagle 2000. Proceedings from an international conference at Björkö, Sweden, 13-17 September 2000. (eds. B. Helander, M. Marquiss and W. Bowerman), pp. 289-295. Swedish Society for Nature Conservation/SNF & Åtta.45 Tryckeri AB. Stockholm.
Acknowledgements Add Letterewe Estate.