Find out what the Isle of Wight eagles have been up to, and visiting eagles from continental Europe, in this guest blog by Steve Egerton-Read, Forestry England and Tim Mackrill from The Roy Dennis Wildlife Foundation.
Spring has sprung and so have the Isle of Wight eagles
Even with the worries that come with the Covid-19 outbreak, we've received a lot of interest in the white-tailed eagles. It's really positive to have so much support for the project. Spring has sprung with a period of warm sunny weather and some strong winds. As a result the young eagles that were released last summer have spread far and wide across England. The birds were fitted with GPS trackers prior to release, allowing the project to monitor their every move following release. In addition to the trackers, each bears a black and white leg ring with a four digit code starting with G, allowing the team to identify individuals. We use these codes in this blog to help you keep track of each amazing bird and their journeys.
Bird G3-93, a male from Mull, is now famous in Oxfordshire and Buckinghamshire but seldom seen. He's been travelling since mid-March and journeyed more than 1,000 kilometres this spring! Initially he headed west towards Slimbridge Wetland Centre, then north to Staffordshire before flying onto the North York Moors. After just over a week in North Yorkshire, he was on the move again heading south via the Peak District National Park to Northamptonshire, passing close to where he spent the winter. He then stayed a few days in East Anglia before returning to the Peaks and the North York Moors.
G3-93 isn’t the only young eagle on the move, the rest of his cohort have all made significant journeys. Bird G3-18, a female, also left the Isle of Wight in mid-March making a series of flights around the west country from her new base in Wiltshire. She then made a direct flight, joining G3-93 on the journey to the North York Moors, where she seems settled for now.
Bird G3-24, the last of the group to leave the island, was seen several times on her six day journey to eastern England. She took just a couple of days to reach the coast of Norfolk, but flew four days against the wind to return to the Isle of Wight.
Perhaps most interesting of all is bird G2-74, who spent much of the winter with G3-24, his female companion. Both birds have been busy learning and developing new skills since returning to the Isle of Wight. They have become quite adept at catching grey mullet along the coastline. Fish is by far their preferred meal and the Solent waters provide a rich source of this food. G2-74 has made several flights from the Isle of Wight, but choosing not to settle away from the island. A couple of short flights over Hampshire and West Sussex and back home are not too surprising, since the Isle of Wight is in view from soaring height. Remarkably he made two long return flights, one around southeast England and another over the southwest. These flights really demonstrate that the Isle of Wight and the Solent coast is home to these juvenile eagles.
Long flights and visitors from overseas
We’ve been really excited to hear about all of the sightings of the young eagles as they fly over people's gardens and we’ve been grateful for all of the messages of support. We’ve also received a number of queries about the eagles’ movements, so we’ve picked a few of the most common ones and answered them in this section.
Why do the eagles make these flights?
White-tailed eagles are long-lived birds and can reach 25 years in the wild, but they take a long time to mature. It will be five years before they are able to breed. In their first two years they explore widely, learning the landscape as they go and often roaming 200km from their nest site, sometimes even beyond that. Once they get closer to maturity most return to their home range, the Solent in this case, and the males will set up territory in hope of finding a mate. Then, hopefully, they will breed.
How do they travel these distances?
White-tailed eagles are big, powerful birds, but it is their 2.5 metre wingspan that allows them to soar effortlessly on columns of hot air known as thermals. Once they catch these thermals, they circle up and gain height. After reaching altitudes of 500 metres or more, it’s easy for these birds to glide between thermals and travel great distances at speeds of 50 kilometres per hour ,or more, barely flapping their wings. At 500 metres above sea level, you or I could see some distance in lowland England, but white-tailed eagles have remarkable eyesight, many times better than ours. At these altitudes not only can they see features in the landscape but it’s also likely they can see other birds of prey from many miles away. The juvenile eagles are inquisitive and will investigate other birds, whether they are white-tailed eagles or a cloud of red kites. Birds of prey also mean potential food, be it carrion or an opportunity to steal a meal, it’s easier than catching your own.
There have been sightings of white-tailed eagles in England that are not birds released by the project. Where are they from and why are they here?
White-tailed eagles in Europe largely suffered a similar fate to the original British population, persecuted throughout the middle ages and into the early 20th century. The remnant populations left behind suffered from the effects of DDT and other pollutants following the Second World War. Our nearest neighbour France saw their last breeding pair lost in the 1950s. The last strongholds survived in Scandinavia and have slowly recovered with a change in human behaviour, and now many European countries are seeing this bird return at last.
On their journeys, some of the white-tailed eagles from Europe occasionally arrive on our shores. This year has seen perhaps as many as four or five of these continental wanderers arrive in England. Identifying the origins of these birds is tricky, but with the right photo sometimes this is possible. Where possible, researchers and conservationists across Europe fit white-tailed eagle chicks with leg rings, like those used in our project, so it is sometimes possible to trace where these birds originate from. In one such case, the project team were able to determine that one of these birds seen in Wiltshire and the New Forest was almost-certainly a third-year bird from Sweden; a journey far further than any taken by the Isle of Wight juveniles as yet! As quickly as this bird appeared, it disappeared. Perhaps it headed elsewhere in Europe or maybe it has settled in a quiet corner of southern England? It’s remarkable how little these birds are seen when they are not on the move.
Most interestingly, once the Isle of Wight birds started moving many more juvenile white-tailed eagles started appearing in England. These travellers have been seen across the south coast and two were seen together in Buckinghamshire at the beginning of April. G3-93 might have seen one of these birds before he left the area, or maybe they were there much of the winter. G3-93 was seen by very few people during this period, perhaps they were unseen too. Buckinghamshire isn’t the only county that has seen a spike in eagle activity. With plenty of sightings along the east coast of England, surely G2-74 or G3-24 encountered one of these European youngsters on their travels! There have also been a handful of sightings in northern England, in County Durham and Lancashire. These could be from the continent or perhaps even from Scotland or Ireland; these counties are roughly equal distance between the other populations in the British Isles and the nearest European population in the Netherlands.
The Netherlands, a glimpse of the future?
White-tailed eagles are on the increase across much of Europe, with birds expanding outwards from strongholds in Scandinavia and Germany. The number of breeding pairs in the Netherlands is increasing each year, with the eagles prospering in a landscape very similar to southern England. Dutch researchers tagged four juvenile eagles in 2019 and these young birds have behaved in a very similar fashion to those from the Isle of Wight. The recent movements of the birds can be viewed on an excellent interactive map which shows that all four have been exploring widely across the Netherlands, France, Belgium and Germany over the last month, covering very similar distances to the Isle of Wight birds.
In continental Europe, white-tailed eagles are very much a part of the landscape. We very much hope that this will become the case in southern England in the future. The satellite data is shedding new light on how the young eagles learn the landscape and shows that, in years to come, there is every chance that wandering birds from countries like the Netherlands could pair up with birds released on the Isle of Wight, helping to link populations. That would be a real sign of success.
Written by Steve Egerton-Read, Forestry England and Tim Mackrill from The Roy Dennis Wildlife Foundation.