Satellite tagging is an important tool of modern conservation science and it is leading to a whole new understanding of sea eagle behaviour in Scotland and around the world. You can find out more about satellite tagging from RSPB Scotland’s head of species and land management here. The particular devices we use weigh 90 grams, or between 1.2 and 1.8% of the birds’ weight. They’re solar powered and fitted with a Teflon harness which is designed to last around 5 to 7 years, after which the hemp thread holding the Teflon together breaks and the tag falls off. This gives us the birds’ exact location anywhere from twice a day in the winter to every hour in the spring, throughout its early years and a short way into adulthood.
Currently we’re learning a great deal about how they disperse in their first year, how they explore the landscape and ultimately which areas are most important to them. Key roost sites and feeding areas are becoming evident as more tagged birds take to the air. With a bit of luck and a lot of patience, eventually we will be able to see how these early experiences lead them to settle in a territory of their own, with a partner they may have met many years before. None of this would be possible with standard fieldwork practices because of the distances involved and the difficulty in identifying individual birds.
There are now 7 sea eagles that fledged from nests in East Scotland carrying GPS satellite transmitters. Four of these hatched just 7 months ago and already most have left their parents protection and ventured out to explore their new home. We’ll look at the dispersal of this year’s chicks in a future blog once they have all moved away from the nest area, so in this blog we look at how the oldest 3 have fared over the last year.
October 2016 to January 2017. White K is in orange, White Diamond is in green and White L is in blue. This shows the first few months of the younger birds’ dispersal and White K’s expedition out to Mull.
White Diamond, Strathspey 2016
White Diamond is a female that fledged from the nest in Strathspey in 2016. Her only contemporary was White L, a male from the nest in Fife. She has been the more adventurous of the two, having covered 6000km in 12 months, compared to White L’s 5000km. During the last 12 months she’s been in every direction, using distinctive ‘loops’ to explore, which contrast strongly with White K’s straight line ‘there and back’ expeditions.
One of her early expeditions took her right out into the farmland of Aberdeenshire and almost to Fraserburgh in the north east corner of the country. Others took her south to Loch Rannoch and west to the fringes of the west coast population where she undoubtedly met other sea eagles. But much like White K she returned to the familiar mountains of East Scotland. Shortly before the Rannoch expedition, which eventually took her within sight of the Isle of Skye, she was in the company of White L in the Angus Glens. White L followed her as far as Loch Rannoch, staying a respectful 7km behind her, but they roosted separately and he flew back the next day.
In April she settled in the Monodhliath mountains, where she has now spent the majority of her time using the rivers and burns to hunt and scavenge. From observations at the roost sites there are plenty of other young sea eagles around, aside from White K probably all west coast in origin. Unlike White K she uses the whole of the mountain range, including the occasional trip over Loch Ness, rarely visiting the same area as the day before.
February to April 2017, showing White Diamonds looping expeditions and White K’s return from Mull
White K, Angus Glens 2015
White K, a male, is the oldest satellite tagged sea eagle from East Scotland. It has now been 2 years and 7 months since he hatched on a nest in the Angus Glens. At the end of 2016 he had travelled all the way out to the isle of Mull on the west coast, where he must have met many other sea eagles. Much to our relief, he headed east again in April and settled in the Monadhliaths. Sea eagles are very sociable and these birds are no exception. White K first met the 2016 female chick from a nest in Strathspey, White Diamond (see below), shortly after she had dispersed into the Cairngorm mountains, where they spent several weeks hunting and roosting together on and off.
May to July 2017. A relatively sedentary time of year of year with White K, the oldest, not travelling more than 20 kilometres from his favoured roost.
Over the last few months they have both been using the Monadhliath mountains, but remaining largely separate and using different the landscape quite differently. It remains to be seen whether this is the quirks of individual behaviour or a pattern associated with their sex. Aside from a short foray into Deeside In October he has remained in this area and has recently been seen hunting over Insh Marshes.
White K in the Monadhliath mountains, September 2017
White L, Fife 2016
White L, a male, fledged from a nest in a Forestry Enterprise Scotland woodland in Fife in August 2016. After spending a few months being fed by his parents, Turquoise 1 (female) and Turquoise Z (male) and building up his courage he left the safety of their protection and ventured off on his own. In previous years young sea eagles from this territory have stayed until February, most likely because there are no other young eagles close by to draw them away, but White L seemed particularly tenacious and left right on time – most fledgling sea eagles will disperse in September or October.
He first headed north through the lowlands of Angus and Aberdeenshire, reaching Inverurie before turning around and heading all the way back to Angus. After a few more weeks in the Angus farmland full of brown hares, rabbits and pheasants, he then headed up into the Angus Glens, probably having spotted another eagle to go and investigate. It wasn’t long before he’d bumped into White Diamond (see above), a female just a few weeks older, and they roosted together in Glen Tanar forest on a few nights.
August to October 2017, showing White L’s exploration of Perthshire and Stirling.
Since then he’s continued to explore the uplands of East Scotland, coming within a few miles of Inverness in the north and Loch Ericht in the west. More recently he has headed south west and explored Pertshire and Stirling, eventually reaching Loch Katrine in the Trossachs, before returning to the Angus Glens.
Sea Eagle Project Officer Owen Selly tells the story of a fascinating discovery
In the spring of 2013, six years after the first release of sea eagles into the Fife countryside after more than 150 years of absence, a few of these magnificent birds started to build nests in East Scotland. A pair of 2009 release birds built their first nest in a Forest Enterprise Scotland woodland in Fife , whilst a 2008 release female and a west coast male built theirs on a grouse moor in the Angus glens.
Turquoise Z (right) and his partner of five years, Turquoise 1, near their nest in Fife in 2016. Image credit Richard Tough.
Their fortunes could not have been more different. The Fife pair went on to successfully raise their first chick and have continued to do so every year since. The Angus pair watched as their nest tree was cut down in an act of targeted vandalism. Shortly afterwards the male disappeared and has not been seen since.
The following year, the female, known as A9/90 after her colour leg ring, found a new three year old mate, Red P, and they built a new nest elsewhere in the Angus Glens. This time they were not disturbed, but the egg she laid was infertile, which is not uncommon in younger birds. In 2015 things were finally back on track and A9/90 raised two healthy chicks with the male Red P.
In 2016 they were again seen on the nest early in the breeding season but something must have gone wrong – by mid-April it became apparent they were not going to breed. Sightings of sea eagles in the area were infrequent and individuals were never positively identified. At the time they were assumed be the same pair, A9/90 and Red P, however in hindsight A9/90 may have already been missing which would explain birds being present but no breeding attempt made.
I climbed up into the nest later in the season to see if they had attempted and failed early, but there was no evidence they had done the necessary preparation, such as making a soft lining in the nest with a shallow depression, known as a cup.
As the 2017 breeding season approached, I was not optimistic that they would return, but in February during a coordinated watch to help locate nesting pairs, two adult sea eagles were seen on the nest.
Staff and volunteers continued to monitor the area and sightings of two other birds nearby were passed off as just being nosey and had visited to see what was going on. We even posted on facebook about a visit by one of them – sea eagles are a social species and often seek out and investigate other eagles.
The new birds were 2011 Red Z, a big female who had previously been seen in Argyll, and none other than Turquoise Z, the male from the Fife nest. He is easy to identify even from a distance as at some point in his early years he lost his right wing tag. It had been known for some time that he occasionally visited the Angus Glens to hunt, despite the distance from his own nest, so it was surprising but not astonishing to see him flying overhead as we watched the nest.
Turquoise Z when he was first seen near the Angus nest in February 2017.
Then, at the beginning of April I set off on my usual hike up to a vantage point overlooking the nest and I was delighted to find a sea eagle laying low amongst the branches, clearly incubating eggs. From my position it was impossible to read the wing tags in the harsh light but the female, A9/90, doesn’t have wing tags so I assumed it was the male, Red P. That day I hadn’t seen any other sea eagles, but I knew the other bird would be off hunting and would return to take their turn incubating the eggs.
With great care not to disturb them I worked my way closer to a new vantage point, 700 metres from the nest. From here I was able to read the wing tags – orange (faded red) with a white Z – Red Z, the big female who had been seen in the neighbouring glen a month earlier. The nest had a new female. The fate of A9/90 is not known, but I was still thrilled to see that Red P had managed to attract this new female and start afresh.
Typical spotting scope view from early monitoring of the Angus nest showing the difficulty of reading wing tags from this distance.
A few days later I returned to check on their progress and I hoped to catch a glimpse of the male, which I did, but he was not who I expected. A large bird came into view over the ridge and dropped rapidly into the valley then swept west towards the nest as Red Z called out in greeting. I couldn’t read the letter on the tag yet but I knew who this was. A single turquoise tag on the left wing could not have been more obvious as he banked sharply away from me and up onto the nest.
I watched in astonishment as Turquoise Z, the male from the Fife nest, landed on the edge of the nest. Red Z got up, let off a few more piercing calls and flew off in search of food. Turquoise Z then took his place on the eggs, settling in for a long shift.
Polygamy – when a single individual has multiple breeding partners – is not unknown in sea eagles but it is very rare, typically they mate for life. It was recorded a handful of times during the early years of the west coast release. In these cases a single male mated with two females on nests a few miles apart and it resulted in the failure of both nests on every occasion.
The demands of raising a chick make it almost impossible for a single male to provide enough food and take on enough of the incubation duties for two females. A single chick can require 1kg of food every day to keep growing and the adults themselves need 500g to stay healthy.
This nest in the Angus Glens is not just a few miles away from his usual nest in Fife; it is 28 miles as the eagle flies and at a higher altitude.
At this point we’d still not found the new nest in Fife; the Fife pair build a new nest every year, just a few hundred metres from the old one and they are usually finished building by January. I was not at all confident Turquoise Z would return to his usual mate, Turquoise 1, despite their success over the last four years, because of the large distance between the nests and was preparing to tell volunteers that there was unlikely to be a nest this year.
Dedicated volunteer and Fife native Richard Tough however was much more optimistic. He has watched these birds week in week out for the last three years and knew it would take more than a far flung affair to break their bond.
I set more of our volunteers the task of watching the forest in the hope of discovering the new nest site and they spotted Turquoise 1 carrying sticks into the same area of the forest where they have nested for the last three years.
We went in for one last sweep and found the new nest in a stand of trees I had searched just a few weeks earlier. She had built a new nest very late and very fast, just in the nick of time. On the west coast sea eagles have usually laid their eggs and started incubating by mid-March, at least two weeks before Turquoise 1 had started building.
There was still no sign of Turquoise Z, but on 9 April, Turquoise 1 started incubating eggs. A few agonising days later, Turquoise Z was at long last seen in Fife, flying into the nest and taking over incubation. It was finally confirmed – he had two females, two nests, four eggs and a lot of flying to do in between.
The first images of Turquoise Z at the Fife nest (top) making some last minute adjustments and at the Angus nest with Red Z just visible incubating. Both in early April 2017.
Over the last three months, a team of nest watch volunteers in Fife, Raptor Study Group members in Angus, RSPB Scotland and Forest Enterprise Scotland staff have watched both nests and I must take this opportunity to thank them publicly for all their hard work.
In Fife we have 30 volunteers watching the nest throughout the breeding season, recording their behaviour and ensuring the birds aren’t disturbed. This is not possible in Angus and we rely on a much smaller team of volunteers. The local famer also keeps an eye on the birds and any comings or goings of people near the nest.
During our observations a pattern started to emerge – Turquoise Z seemed to be alternating every other day between the two nests, travelling from Fife to Angus mid-morning. On several occasions he was seen leaving the Fife nest and arriving at the Angus nest between 60 and 90 minutes later. A long journey for this remarkable bird, who still had to take shifts incubating, provide food for both females and feed himself.
Even with this extraordinary effort the females had to take on much more of the incubating than they would normally. But they were up to the task and in May I got my first glimpse of two tiny, fluffy grey heads on the Angus nest, followed a week later by two more on the Fife nest. This is my favourite moment in this job, seeing the chicks for the first time and knowing they have safely made it through the precarious incubation stage where even a minor disturbance in cold weather can result in failure.
Turquoise 1 and the larger Fife chick at 4 weeks old in June 2017.
The chicks are still very vulnerable for the next three weeks however as they are unable to maintain their body temperature and need the parents to cover them and keep them warm when it’s cold or shade them from the sun when it’s hot, a behaviour known as brooding.
At some point in the first week after hatching one of the Angus chicks died, but the other flourished and continued to grow rapidly. On the Fife nest the chicks almost reached six weeks before one of them also died. It is quite rare for the second chick to die at such a late stage, indeed sea eagles often fledge two, but this has happened at the Fife nest for the last three years. Sadly it seems that one of the chicks becomes dominant and starts to outcompete the other for food.
Red Z at the Angus nest with surviving chick just visible behind her in June 2017, aged 7 weeks.
By July the remaining chicks, now one in each nest, reached eight weeks old. At this age they are almost full size but not yet able to fly, so this is when we fit them with satellite tags and wing tags. These are important tools for conservation as they allow us to study their behaviour – where they roost, where they hunt and even how they interact with other sea eagles. Three sea eagles from previous years that were fitted with satellite tags are still exploring East Scotland and giving us invaluable insight into how they spend their first few years of life.
The surviving chick at the Angus nest in early July aged 8 weeks, having just been put back in the nest after being fitted with wing tags “Blue V” and a satellite tag.
The female chick on the Angus nest was fitted with blue wing tags with a white V. The Fife chick, also female, was tagged with blue wing tags with a white X. At the time of writing they are 13 and 12 weeks old respectively and Blue V has taken her first tentative flight into an exciting new world. Blue X will surely follow within a few days. Given all they have known for their short lives to this point is a pile of twigs and branches two metres across, this must be quite an experience.
They are able to cover large distances using very little energy, thanks to their huge 2m wing span and their eye sight is one of the best in the animal kingdom. Combined with their social nature this makes meetings inevitable and all of the young sea eagles we have satellite tagged so far have met and spent time together. As long as they survive the difficult early months out on their own, it is almost a guarantee that Blue V and Blue X will meet each other before the end of winter, not knowing of course that they share the same father.
The surviving Fife chick, Blue X, during tagging in early July. Image credit Richard Tough.
These two nests are now connected by this curious quirk of behaviour, but it is striking how different their stories have been.
In Fife Turquoise 1 and Turquoise Z have bred successfully for the last five years, living alongside humans seemingly unperturbed by cars, planes, helicopters, dog walkers and everything else that comes along with us.
In the Angus Glens, far away from our towns and villages, the first three adult sea eagles that have been involved in breeding attempts have vanished along with one of the previous years satellite tagged juveniles – three more have disappeared elsewhere, also on grouse moors. The circumstances for each individual remain a mystery, but sea eagles usually pair for life so the pattern is hard to ignore, especially in light of the overwhelming evidence for satellite tagged golden eagles disappearing under suspicious circumstances on grouse moors.
There is cause for hope however. Already the presence of these sea eagles from the reintroduction in Fife has attracted birds from the much larger West Scotland population. Until 2016 all but one of the seven chicks fledged from East Scotland nests had died within their first year, but now three have reached this milestone and continue to do well. In another few years they may be building nests of their own.
Timings of the changes at the Angus and Fife nests, with the tiles representing individual adults.
It's been a busy 7 months for 'Celebrating Nature with Schools' team and I'm delighted to say we have reached the milestone of engaging 750 local primary pupils from Perth & Kinross, Dundee, Angus and Fife with the project. Thanks to £20,000 of funding from players of the People's Postcode Lottery and People's Postcode Trust we have been able to provide transport for schools to join us at locations around the Tay Estuary, including Tentsmuir National Nature Reserve.
Each session has taken pupils on the yearly life cycle of the white-tailed eagle, beginning with learning about the size, weight and different types of feathers of a sea eagle.
Pupils then explored pair bonding and choosing a nest site (blindfolded to add to challenge of building trust), before building a life size nest using their bare feet and mouths just like a sea eagle! Ok maybe we didn't go that far, but it was fun to see how many children began to take their shoes and socks off when it was suggested!Pupils then learnt about the incubation period, tuning in their hearing and highly developed eagle sense of sight, by using sit spots to record what wee beasties they could see and hear around them. Bell Baxter High School wrote this amazing group poem during their collective sit spots, whilst undertaking their John Muir Award and exploring the eagles' hunting ground.
Predator and prey games, including the action packed 'food pirates' activity drew out the competitive spirit of each class.
Errol primary were particularly lucky to even see Turquoise Z fly by on a hunting mission during one such game! He was being mobbed by some local crows, which he deftly saw off with two 360 degree barrel rolls and a flash of his talons skywards.
Owen, our Sea Eagle Officer who out visiting the project for the first time, must have been our lucky charm as it was the only time we saw any sea eagles during a teaching session.
After dodging some particularly heavy thunderstorms we wrapped up the programme with a series of outreach sessions at Fife Coastal and Countryside Trust's Loch Ore Meadows. St Patrick's, the local primary school walked down to the park as part of their health week and learnt that sea eagles (just like humans) need shelter, food, rest and relaxation to remain healthy.
So now with the summer holidays upon us, it's time to reflect upon the success of the project and plan for next year's delivery. It's been great fun sharing our passion for these magnificent birds with the next generation of nature's champions, and I'm pleased that the feedback from schools has been really positive. Following their trip the pupils of Inverbrothock Primary School said;“Seeing where the eagles hunt made it all seem so much more real.”
“Doing the activities was a much more interesting way to learn about the eagles than talking about it in class.”
“I am amazed how big their wings are!” and
“It is brilliant that the eagles are returning to Scotland!”
Their class teacher reflected further on the experience;"The children had a fantastic experience learning about white-tailed eagles in the beautiful outdoor surroundings of Tentsmuir Forest. They were able to understand the life-cycle of the eagles through active learning activities including a race to find food, making a life-sized nest, and using the five senses to think about our surroundings.”We are hoping to be able to replicate a similar programme next year, so any primary teachers please do get in touch and register your interest with Community Outreach Officer, Sara Rasmussen; email@example.com
Finally, once again thanks to the People's Postcode Lottery, Kirsten, Elizabeth, Conor and Lynsey (our amazing team of volunteers) and all our supporting partners who have made the project possible; Forestry Enterprise Scotland, Scottish Natural Heritage and Fife Coastal and Countryside Trust . Enjoy the summer!