What are White-tailed Eagles?
The White-tailed Eagle, or Sea Eagle, is Britain’s largest bird of prey with an 8 foot wingspan. Adults are predominantly brown, with a pale head and white tail. In flight it has long, broad wings and a short wedge-shaped tail
Are White-tailed Eagles native to the UK and England?
The White-tailed Eagle was formerly widespread across southern Britain before suffering intense persecution during the Middle Ages, which led to its eventual extinction as a breeding species by the early nineteenth century. The population in the United Kingdom was estimated to be as high as 1000-1400 pairs in 500 CE, with breeding pairs located throughout southern England. An analysis of place names interpreted as indicating the presence of White-tailed Eagles indicates that the species likely bred across the whole of the south coast, from Cornwall to Kent. The last known pair bred on Culver Cliff on the Isle of Wight in 1780.
What will the project involve?
The project aims to restore a population of White-tailed Eagles to West Norfolk and to the surrounding region. This will involve the release of young White-tailed Eagles at Wild Ken Hill. The released birds will regard the area as home, and some will settle to breed in the local area once they reach breeding age. This is the second phase of the restoration of White-tailed Eagles in England. A reintroduction project began in 2019 on the Isle of Wight, and thirteen birds have been released to date. White-tailed Eagles have been successfully reintroduced to both Scotland and Ireland and using the same long-established methods now being used on the Isle of Wight.
Why are you doing it and what are the benefits?
White-tailed Eagles were once widespread across the UK but are now one of our rarest species and listed as species of Conservation Concern. They are a missing part of England’s native biodiversity and were lost entirely through human activities, mainly intense persecution. Restoring a breeding population of White-tailed Eagles in West Norfolk would help to link the establishing population on the South Coast with those in continental Europe, as well as others in Scotland and Ireland. As such it would enhance European-wide efforts to conserve the species.
Apex predators such as White-tailed Eagles are fundamental in maintaining the balance of ecosystems. For example, they have supressed the populations of feral geese in the Netherlands by predating gosling Barnacle and Greylag Geese, and also control the populations of meso-predators, such as Common Buzzards, as recently-recorded in Lithuania. Thus, the project would restore an integral missing part of coastal and wetland ecosystems.
In addition, White-tailed Eagles are an important flagship species in coastal and wetland ecosystems and we can use them to highlight the conservation of these special places.
Dominic Buscall, Project Manager at Wild Ken Hill, outlines in further detail the motivation for bringing forward the proposals.
Why not wait for them to re-colonise naturally?
White-tailed Eagles do not breed until they are at least 4-5 years old and have low breeding success. In addition, most prefer to breed with or near established pairs, close to their natal site. This means that population increase and range expansion are very slow. Eagles are likely to take decades to recolonise West Norfolk and the surrounding area naturally, and reintroduction project would significantly speed up this process.
Why is the Wild Ken Hil and West Norfolk a good place for the recovery of this species?
Many parts of East Anglia are capable of supporting breeding White-tailed Eagles, but Wild Ken Hill is considered a highly suitable location for the release. It is located close to excellent foraging areas along the Norfolk coast, there are numerous potential nesting sites in local woodlands, and quiet areas for immature birds. A significant rewilding, conservation, and regenerative agriculture project is also underway at the site. Since release the Isle of Wight birds have generally favoured areas with scattered woods and open fields and one of the released birds, G393, was present in West Norfolk between 1st August 2020 and early January 2021. This bird has ranged between various private estates in West Norfolk and has visited the Wash on a number of occasions. A second Isle of Wight bird also visited West Norfolk in April.
Who is running the project?
The project is a partnership between Wild Ken Hill and the Roy Dennis Wildlife Foundation. Roy Dennis has been instrumental in the recovery of White-tailed Eagles in Scotland and has extensive experience of the techniques that will be used.
When is the project happening?
It is hoped that the first juvenile White-tailed Eagles could be released in 2021. Further releases would then take place over the next four summers, with 6-12 birds being released each year. It is important to consider that only approximately 35-40% of these birds are likely to reach breeding age – see more below.
What number of birds will survive and eventually breed in Norfolk?
In Ireland 75% of released birds survived their first year and annual survival was 90% thereafter, while in Scotland around 37% of released juveniles have reached breeding age (5 years). To date four of six birds released on the Isle of Wight have survived their first year.
If the first birds are released, as planned, in 2021 breeding is not likely to occur until at least 2026. It is hoped that an initial population of 6-8 pairs will become established in West Norfolk and the wider region within 10-15 years.
Some released birds may disperse and join the Isle of Wight/South Coast population, while others may settle in the Netherlands. The presence of White-tailed Eagles in Norfolk could likewise attract wandering birds from these other populations.
What is the size of their territories? How far would a bird travel?
Young White-tailed Eagles wander widely before they breed, but most eventually settle close to their natal site. Research in Scotland revealed that juveniles often range 200 km or more in their first two years, before returning to breed closer to their natal site (median natal dispersal (i.e. distance from nest/release site to first breeding location) 21–45 km in males and 47–58 km in females). In recent years birds thought to be from the expanding White-tailed Eagle populations in continental Europe have been seen in eastern and southern England. For example, a Swedish juvenile was present in Hampshire and surrounding counties between December 2018 and April 2020 at least. Four-five other continental birds were also recorded in England during spring/summer 2020.
The four Isle of Wight birds that survived their first winter, explored widely in spring 2020. Two of the birds visited Norfolk during this period and G393 spend over five months in West Norfolk (as described above) having spent much of the spring and early summer in the North York Moors. Another released bird flew as far north as the Firth of Forth before spending two months in the Lammermuir Hills in southern Scotland. It then returned to the Isle of Wight in early September.
Once they begin breeding adult birds have a much smaller home range, and are likely to remain sedentary throughout the year. Evidence from Scotland and elsewhere in Europe indicates that active nests tend to be at least 5-15 km apart, even in the areas with the highest population densities. They are then further limited by the availability of suitable breeding habitat, with the birds favouring woodland located close to the coast or large inland waters. In the short term (10-15 years) we expect of population of 6-8 breeding pairs to become established within 50km of the release site, although it is difficult to predict exact settlement patterns.
Once the West Norfolk population has become established then a faster rate of population growth and geographical spread might be expected, as observed in Scotland where there are now 130 pairs, dispersed across much of northern and western Scotland, 45 years after the first pair attempted to breed in 1975. As the population grows there will be increased competition for breeding territories and this will encourage young birds to disperse further.
In an extremely well-studied population of White-tailed Eagles in the region of Schleswig-Holstein in northern Germany, the density of breeding eagles in optimum habitat is 1.4 pairs per 100 km² (Krüger et al. 2010), but lower in less favourable areas (0.3 pairs per 100 km²). Thus, the expected carrying capacity of the region as a whole (15,763 km²) is 122 pairs.
Based on the density of breeding White-tailed Eagles in optimum habitat in northern Germany (a realistic comparison to eastern England), it is likely that given its size (5371 km²) the whole of Norfolk could potentially support a maximum of 30-40 breeding pairs, but it would take several decades for the population to reach that level and birds are likely to disperse to other areas of East Anglia first.
Where will the birds come from for the release programme?
Suitable source populations have been identified that would ensure sustainability of the source population and genetic diversity among the UK population, but at this stage the source population remains confidential. The birds would be collected under licence from an area where White-tailed Eagles are widespread and live without conflict alongside local people. A single chick would be taken from a brood of two or three.
Who would licence / approve the project?
A licence is required from Natural England – the UK Government’s wildlife licensing body – to release White-tailed Eagles, which are listed on Schedule 9 of the Wildlife and Countryside Act. Relevant permissions would also be gained from the institutions governing the source population.
What is the process for getting permission to release these birds?
A comprehensive feasibility report will be submitted to Natural England as part of the licence application process. This will outline the scientific and conservation rationale for the project, and contain the results of a public consultation. A similar study was produced for the Isle of Wight project, and this can be viewed here.
Why do you want to help this species and not other species already under threat in East Anglia?
As apex predators White-tailed Eagles have been shown to have clear ecological benefits. As already described they have supressed the populations of feral geese in the Netherlands, and control meso-predators, such as Common Buzzards, as recently-recorded in Lithuania. Thus, the project would restore an integral missing part of coastal and wetland ecosystems.
The White-tailed Eagle is a flagship species for wetland and coastal conservation. Restoring a population of these spectacular birds to West Norfolk and surrounding area will raise the profile of conservation among the general public and help to highlight important conservation issues affecting wetland, estuarine and coastal habitats and the species they support. As such it will benefit a range of other species both directly and indirectly. Furthermore, funding for the project will be sought from a range of different sources that will not conflict with existing or planned projects in the area.
Where exactly will the birds be released?
The birds will be released at a confidential location with no public access at Wild Ken Hill. Once released, the birds will disperse around the local area and then further afield. It is notable that the Isle of Wight birds are often very elusive and often go many days and even weeks without being seen.
We intend to keep the local community, visitors and interested groups updated on the bird’s development and work with other local organisations and stakeholders to establish opportunities to observe them as the project progresses.
How do you encourage the birds to remain in the local area after you release them?
Food will be provided at designated feeding areas at Wild Ken Hill. This replicates the way adult White-tailed Eagles continue to provision their young after they have fledged, and will continue throughout the first winter to encourage the released juveniles to remain in the local area. Nevertheless, we expect the first birds would begin dispersing into the winder area during the autumn after release.
How will you keep track of the birds?
The birds would be fitted with satellite-tags, colour rings and VHF transmitters prior to release. This would enable their movements to be tracked remotely and to help us to identify individuals more easily. This data will be made available online, but the location of birds will not be publicised when they are on private land. Updates on the Isle of Wight birds can be viewed here. The satellite data has provided valuable information on the movement of Isle of Wight birds since release (see above) and helped to demonstrate that they have learn to live successfully in the English landscape.
Where can I go to see the birds?
Where there is existing good public access and suitable visitor facilities, eagle viewing points would be estabished to provide people with the opportunity to see the eagles in flight.
Sites in more sensitive areas will be kept strictly confidential in order to protect the birds and to ensure present land use is not disrupted by the additional footfall. This approach has been successful on the Isle of Mull where eagle tourism makes a significant contribution to the local economy.
Will the project benefit the local economy?
In Scotland eagle tourism is popular and recent RSPB commissioned reports have shown White-tailed Eagles generate up to £5 million to the economy of the Isle of Mull each year, and £2.4 to the Isle of Skye. It is probably that White-tailed Eagles would give a boost to the West Norfolk economy.
Do white tailed eagles need cliffs for nesting?
No. Although White-tailed Eagles do nest on cliffs, they will also breed in tall mature trees. In some areas of the world they even breed on the ground.
What do they eat?
As a generalist predator, White-tailed Eagles take fish, birds and small to medium-sized mammals and also scavenge carrion, which can be an important element of the diet throughout the year. They tend to favour the most seasonally-abundant prey. For example, fish are particularly important in spring and summer, with waterbirds often favoured in autumn and winter.
The diet of the birds released on the Isle of Wight has been monitored in detail since release. This has shown that the birds have regularly caught Grey Mullet and Black Bream around the coasts, and rabbits on the downs. Interestingly, one of the released birds was also observed catching and eating cuttlefish in the Solent on a number of occasions. Two birds summered in the North York Moors, and during this period they fed predominantly on rabbits, as did the bird that was present in the Lammermuir Hills in southern Scotland.
Black-headed Gulls have been a key prey item of G393 during its prolonged stay in West Norfolk, and this bird is also known to have predated hares. During the juvenile eagle’s first winter carrion was a key source of food, and this included deer, dead waterbirds and gamebirds.
The White-tailed Eagle’s preference for fishing in shallow water mean that inlets and bays along the Norfolk coast would be favoured foraging locations, with fish such as Grey Mullet likely to be favoured, as they are on the South Coast. The Norfolk Broads could also provide fishing grounds. The Norfolk coast supports large numbers of migratory water birds, which are likely to form a key element of the diet in winter.
In Denmark, where there are now over 100 pairs of breeding White-tailed Eagles (from none in the early 1990s), it is thought that most geese and ducks taken by eagles are likely injured or sick. They regularly search tidelines for washed up dead fish, birds and sea mammals. The high concentrations of wintering wildfowl and waders in Norfolk and the surrounding area mean that foraging eagles will regularly encounter bird carcasses, and they will also take any washed-up dead fish or marine mammals as they search shorelines for food.
It is notable that G393 has flown out into the Wash on a number of occasions, and may well have been searching for carrion in this way. A recent study in Germany showed that carrion account for almost 30% of White-tailed Eagle diet in winter.
White-tailed Eagles regularly predate gosling Barnacle and Greylag Geese in the Netherlands, and so we anticipate that Greylag and Canada Goose goslings to be key prey items during summer in East Anglia. Rabbits are also likely to constitute an important part of the diet throughout the year.
Will the eagles take lambs or other livestock?
There have been no incidents of predation of livestock or poultry by any of the 13 birds released on the Isle of Wight since 2019, including the bird G393 which spent over five months in West Norfolk, including around many outdoor pig farms.
During the public consultation on the Isle of Wight, prior to the release, concerns were raised by some that White-tailed Eagles may predate lambs or other livestock. We have been careful to listen to these concerns, to look at the scientific research around this issue, and to speak to people with direct experience. Evidence indicates that some White-tailed Eagles scavenge dead lambs in Scotland and very occasionally take small and weak individuals of blackface sheep on hill grazings. However, this is predominantly due to the open range nature of agriculture and bad weather as well as the lack of alternative wild prey in some biologically poor regions.
In view of the concerns that had been raised, the project team visited the Netherlands to speak with researchers monitoring the expanding Dutch White-tailed Eagle population. There White-tailed Eagles breed in areas grazed by sheep, but the researchers, who have kept detailed feeding records, have recorded no cases of eagles taking lambs or any other livestock and there is no conflict with farming. There is an abundant supply of wild prey – particularly water birds and fish – in the Netherlands and a similar scenario is likely in West Norfolk given the high natural prey availability in the local area. In Ireland, where there are now ten breeding pairs of White-tailed Eagles following a reintroduction project, there have been no cases of eagle predation on lambs and most farmers are either neutral or supportive of the project, despite initial concerns.
A key element of the project is to liaise closely with the farming community from the outset, and respond to any local issues immediately should they occur. Representatives from the farming community, as well as other key local stakeholders will be invited to join the project’s advisory group. 16 landowners and farmers have already written to Natural England to formally support these proposals, and a large number of others have offered their informal support.
A comprehensive exit strategy has been agreed with Natural England for the Isle of Wight project, should unforeseen problems arise. However, it is important to note that there has been no conflict with livestock since the first White-tailed Eagles were released on the Isle of Wight in August 2019. G393 has spent time close to pig farms since arriving in West Norfolk on 1st August, but there have been no reported problems.
Will they predate gamebirds?
During the winter the birds released on the Isle of Wight were recorded feeding on dead gamebirds in several areas. As such it is likely that birds released in Norfolk could spend some time in areas with pheasant or gamebird shoots during the winter. Nevertheless, there has been no conflict with shooting interests on the Isle of Wight or elsewhere and the shooting community is represented on the project’s steering group. The project will liaise closely with estates in Norfolk, and a representative from the shooting community will be invited to join the project’s advisory group.
Are they a threat to pets and can they be dangerous?
No. There is no threat to pets and the birds do not pose any threat to people.
Are they a threat to other wildlife?
No. There have been many studies on the diet of White-tailed Eagles across Europe and no quantifiable negative effects have been demonstrated on any one species. This is because White-tailed Eagles have a broad and varied diet and tend to favour the most seasonally abundant prey, including carrion. It is also important to consider that White-tailed Eagles will tend to target injured, sick or dying waterfowl when hunting.
In many parts of Europe White-tailed Eagles coexist with the same range of species that occur in wetland and coastal habitat in West Norfolk and the wider East Anglian region in both summer and winter, with no negative effects. Colonial nesting birds such as gulls and terns, and waders, including Black-tailed Godwits, fly up and harass eagles before they reach breeding colonies. Evidence from the Netherlands shows that they prefer to avoid these areas.
There were some concerns that the presence of White-tailed Eagles on the South Coast would increase pressure on several SPA sites in the Solent where recreational disturbance is an ongoing problem. However disturbance by White-tailed Eagles is not considered an issue by Dutch researchers at internationally important wetland sites such as Krammer-Volkerak. This SPA and Nature 2000 site has a very similar species assemblage to both the Solent and Norfolk, with large numbers of Dark-bellied Brent Geese, Teal, Black-tailed Godwit and Ringed Plover all present along with resident White-tailed Eagles.
It is important to consider that White-tailed Eagles spend much of the day perched. Recent research in Germany demonstrated that eagles prefer the “sit-and-wait” for prey strategy, and as such are only on the wing for short periods each day, thereby minimising the amount of disturbance they create. This has been corroborated by field observations and satellite tracking of the Isle of Wight birds, which spent prolonged periods perched in quiet areas. Furthermore, migratory species such as Brent Geese encounter White-tailed Eagles across their migratory range. The breeding range of the two species overlaps in some parts of Arctic Russia and the migrating Brent Geese may encounter White-tailed Eagles at many sites on the flyway through the White Sea and Baltic Sea, and along the North Sea coast.
Will they take wading birds and ground nesting birds?
As a generalist predator, White-tailed Eagles tend to favour the most seasonally abundant prey. This means that in spring and summer fish, rather than birds, are likely to form the key part of the diet. Furthermore, evidence from other parts of Europe, such as the Danube Delta, where there are 20-25 breeding pairs, indicates that White-tailed Eagles have no impact on ground-nesting birds. Wildfowl are taken in preference to waders, as demonstrated by the fact that the eight most commonly caught bird species taken in the Danube Delta were ducks and geese, with Coot the most commonly taken species, followed by Mallard. The same is true in the Netherlands where wildfowl are the favoured prey with goslings of Greylag and Barnacle Geese forming a key part of the diet in summer, along with Coot. White-tailed Eagles tend to take injured and weak individuals.
What will the eagles do to the small bird populations?
White-tailed Eagles will have no effect on small birds. In some places they are known to take young Carrion Crows and Magpies which themselves are far more likely to have an impact on small birds. Likewise, recent research has demonstrated that White-tailed Eagles predate Common Buzzards.
When the birds fly over wetlands will they scare off all our waders and wildfowl?
Evidence from the Netherlands indicates that disturbance to waterbirds birds by White-tailed Eagles is similar to that caused by Peregrines and Great Black-backed Gulls, and waders and other species quickly become habituated to their presence. The eagles spend most of the day perched, often within views of large numbers of waders and wildfowl. Satellite data indicates that the bird G393 has spent over 90% of its time perched.
As explained above there had been concerns that the presence of White-tailed Eagles would increase pressure on several SPA sites in the Solent where recreational disturbance is an ongoing problem. This has not been the case since the release of the first birds in August 2019, as evidence from the Netherlands and Germany indicated would be the case (see above).
In Denmark there has been a rapid increase in the population of breeding White-tailed Eagles in the last 30 years, and there are now more than 100 breeding pairs, and also a large pool of non-breeding sub-adults. The eagles favour offshore islands and islets for resting, where they potentially compete for space with breeding terns and gulls. However, there has been only one case on an island in Mariager Fjord in eastern Jutland where the increasing presence of eagles may have resulted in the eventual abandonment of a colony of Sandwich Terns. Biologists who monitor colonial nesting species in Denmark are not aware of any other examples of colony desertion by gull and tern species due to eagle presence. In fact there are several island sites, which eagles frequent throughout the summer, which retain their breeding gull and tern colonies. Furthermore, there is no evidence that White-tailed Eagles have had a negative impact on flocks of staging Dark-bellied Brent Geese in the Danish Wadden Sea in autumn.
There are already a lot of scavenging birds, such as Herring Gulls, why do we want another scavenger?
White-tailed Eagles are far shyer than birds like Herring Gulls, and won’t scavenge food from close to people in the same way. They are more likely to scavenge dead birds, mammals and fish in open areas close to or beside water.
What impact will the birds have on fishing, both river and sea fishing?
White-tailed Eagles are likely to have minimal impact on fish stocks. They are likely to take the majority of their fish in shallow coastal water, and will favour seasonally abundant species such as Grey Mullet. Furthermore, their ability to exploit other prey such as cormorants, other birds and mammals means that fish populations will not be under threat.
Is this of national importance?
The UK Government’s 25 year Environment Plan, published early in 2018, includes the reintroduction of White-tailed Eagles as a priority action. The White-tailed Eagle is also listed as a species of Conservation Concern in the UK. Regionally we think this will be regarded as an extremely exciting project and the future potential of watching adult White-tailed Eagles soaring over the Norfolk coast will be exciting for wildlife enthusiasts, the local community and visitors to the area.