A Treasure and a Challenge

Hen harriers are charismatic birds. They are compelling and delicate birds perfectly suited to life in the northern hemisphere. Capable of traveling long distances with ease as well as utilising a range of habitats makes them an adaptable predator.

"Years ago, I recall watching a roost site on the great prairies of Montana, we estimated seeing 175 birds all gathering together at dusk to roost. A great spectacle! Perhaps one day Scotland can play host to such a natural wonder."  Ronan Dugan, WildLand Limited

Perhaps, it's also worth considering the hen harrier situation in some of the Scottish Isles such as Orkney or the Uists where the birds are more abundant. Here the birds appear to have fewer challenges and are commonly seen close to human activity. Perhaps, one day much of the Highlands or at least our National Parks can replicate this.

In Scotland most of our hen harriers nest on open moors. Here at WildLand, we observe them most frequently nesting on our regenerating native moorland. This is encouraging as we will have ample and more resilient habitat for them in the future.

Perhaps, conditions on WildLand will continue to improve in the absence of intensive pressures as this will benefit our small mammal and bird populations which the harriers rely on during their breeding season. As we monitor the predators, we also believe it is crucial to monitor their prey. We have various studies in place. The Cairngorms Connect Predator Prey study is one example. It is also worthy of note that there is currently no predator control being undertaken across WildLand and this has been the case since around 2019.

At WildLand Cairngorms our harriers begin to nest at the end of April.

After a busy period of sky dancing and nest building the female harrier will lay her eggs. Hen harriers can lay between 3 and 7 eggs and have an incubation period of 29 - 31 days. Usually our nests are located in heather dominated areas. However, in this photo a male harrier appears from a nest within an area of regenerating bog myrtle, more typical of a harrier nest site on the west coast. 

Here a brood of three hen harrier chicks can be seen at their nest. A large prey item can also be seen on the nest, this is likely a red grouse.

During our monitoring efforts, we strive to only visit the nest once the eggs have hatched. There is a possibility that visiting ground nesting birds such as hen harriers could lead to unnecessary stress and disturbance. Ideally, all monitoring would be done from a distance. However, when tagging chicks, we must visit the nest to determine the age of the chick(s) so we can tag them at the optimum age. When studying such species there is always a compromise. Here the compromise lies in our wish to fit tags to gain a better understanding of their movements, threats and requirements to assist their longterm productivity.

Tagging is done when the chicks are around three - four weeks old. 

Here the team fit GSM tags to two young female harriers.

At WildLand, in the future we will only fit tags to female hen harriers as they have a larger body mass (like most birds of prey) and are therefore more capable of carrying a tag which weighs 10g. 

In raptors the size difference between males and females is known as 'reversed sexual size dimorphism'!

Wildland Hen Harrier 9 was tagged on 19/06/2020 in Glen Tromie, within WildLand Cairngorms. This young male harrier spent much of his first year in the northern Cairngorms National Park.

During the winter of 2020/2021 we lost signal from WildLand Hen Harrier 9 near the town of Callander on the edge of Loch Lomond and The Trossachs National Park. We presumed that was the last we would hear and the battery power had remained low. However, during some bright sunny days in late April the tag started to transmit from a field near Callander. The carcass of the bird was recovered along with the tag. No suspicious circumstances were suspected. 

WildLand Hen Harrier 10 is a female. She was tagged in GlenTromie on 22/06/2020. She was one of three chicks to fledge from this brood, her brother being WildLand Hen Harrier 11.

During the latter part of 2020 and into 2021 she spent most of her time in Strathspey, often roosting on RSPB's Insh Marshes Nature Reserve. From here she made daily trips into the Monadhliath Mountains to the north and Cairngorms to the south. We admired the toughness of this young harrier as she endured the prolonged winter weather here in Strathspey. From time to time she did embark on wider travels.

As spring came around we watched eagerly as she returned to WildLand Cairngorms to breed in her first year. She paired with an adult male and fledged three male chicks. One of these chicks was tagged and is WildLand Hen Harrier 19.

She also bred successfully in a similar location in 2022, 2023 and again this year in 2024!

In early May 2021, we received signal from WildLand Golden Eagle 1. 

The signal we received from Highland Perthshire was not normal however. WildLand receives notification if the tag remains in an unusual orientation, for example if the tag is upside down. This was the case in this situation. We could see the location was coming from some isolated trees so we suspected the tag had come off or the bird had died at a roost site. 

We acted swiftly and went to investigate and thankfully the tag was found but the bird had survived. The young eagle had found a weakness in the harness and managed to pull it apart.

WildLand Golden Eagle 3 was also tagged in 2019 at Gaick on WildLand Cairngorms. This male eagle was tagged on 03/07/2019.

We monitored his movements without concern until early March 2021. On 05/03/2021 we received our last transmission in the central Cairngorms National Park. At this time the battery was at 91%. 

Around this time, we, at WildLand Cairngorms observed large amounts of snow mobile traffic (perhaps used to persecute foxes) on land adjacent to ours. This technique of using snow mobiles to control other important predators such as foxes, and the welfare concerns associated with it, should perhaps be added to the licensing of grouse moors or banned within our national parks. It was also around this time a golden eagle was found poisoned on Invercauld Estate so we wonder if there was a wider movement to target predators - both avian and mammal - when the conditions were optimal for wide and swift travel by snow mobile. 

We now share the story of WildLand Golden Eagle 7 which was tagged at Gaick on 02/07/2020. From our detailed measurements we are certain this eagle is a female.

We were able to track the movements of this bird until 16/03/2022. The last signal we received was in mountainous country in the east of the Cairngorms. We did not hear anything until very recently...please read on!

Here is a photo of the magnificent young WildLand Golden Eagle 7 taken on a trail camera at a roosting site in the eastern Cairngorms. The eagle can clearly be identified by the numbered ring on its left leg. Of note, the trail camera was set up by the individual who tagged this bird. We were all delighted to know the bird is still doing well!

It is clear to see in this photo that the eagle has shed its tag and this is why we lost signal from this bird on 16/03/2022. The tag harness is designed to come off after a period of time so we are content to witness this has been the case with this young eagle. 

Although, perhaps this young eagle has not chosen the safest of homes...

This young eagle, along with its mate, has decided to build a nest in these rather beautiful old Scot's pine trees on the left of this remote glen. This location certainly seems like a wonderful place, ideally suited in habitat and topography for breeding golden eagles.

However, as you can see from this photo, taken on 15/04/2023, by a Raptor Study Group member, muirburn is taking place close to the nest. Infact, muirburn was recorded within 150m of the active nest! These actions likely prevented the eagles from breeding successfully last year.

As a result of monitoring this young eagle, and the land management actions witnessed, WildLand, as a land owner, are fully supporting the Scottish Government's proposals to license muirburn and grouse moors. While many landowners are encouraging species and habitat recovery on their land, WildLand believe, such a licensing scheme will help to further protect young golden eagles such as WildLand Golden Eagle 7 and other cherished species and habitats.

Here you can view the movements of WildLand Golden Eagle 9.

After being tagged at Gaick Estate, within WildLand Cairngorms, on 01/07/2020 this young eagle has traveled widely across the Highlands and some of the islands.

Please see the map below for a more detailed view of it's recent movements.

Goshawk usually nest in conifer forests. Here is one of our nests within an area of Scot's pine plantation on WildLand Cairngorms.

In 2021 we located two nests, both new pairs recently established in the area. 

In 2022 and 2023 we have recorded just one pair breeding. Below is an account of tagging the three goshawk chicks in 2021.

The nests were accessed once the chicks had hatched to obtain the necessary information for our future tagging visit.

Here three young goshawk are approximately two weeks old.

Only two of these chicks survived to fledge. Siblicide is relatively common in raptors where the youngest and usually the smaller chick is killed by it's bigger and slightly older siblings. Food supply and provisioning plays a big role in the development of the chicks and can influence such siblicide. 

Skilled and qualified climbers were used to access the nest and lower the chicks down for tagging.

Here are two young goshawk about a month old. They are both fitted with GSM solar powered tags of 20g and 25g, the heavier tag going on the slightly larger female chick. The red colour rings on their legs have engraved letters which will allow us or others to identify them by sight or on camera traps in the future.

However, not all stories have a happy ending.

We tagged our third goshawk, a single female chick on 01/07/2021.

We received some data to say the bird had likely fledged successfully. However, around 15/07/2021 we became concerned the young hawk had stopped moving. On 28/07/2021 we recovered the tag which had been chewed by a mammal. No sign of the carcass was found. 

We are unable to determine the cause of death for this young goshawk, however, it is possible that this youngster did not survive due to lack of food or predation by another raptor. When rearing chicks in their first year it is relatively common that raptors will loose, or not fledge their young successfully.

In late June, along with project staff from the south of Scotland we collected one of the eagle chicks from the nest on Wildland Cairngorms. A careful process was undertaken with trained personnel and a vet on site.  

The young eagle was carefully chosen for its age and sex. It was immediately paired with another young eagle in its new home in the South of Scotland. The eagle had a full crop at the time of collection.

A careful transportation of the young eagle was undertaken to get it safely to the roadside. 

The project team and young eagle traverse a hillside within WildLand Cairngorms.

The project team remarked at how wonderful it was to spend time in a regenerating landscape in the absence of sheep and (largely) deer. 

The young eagle was safely transferred into another crate for safe transportation to its new home in the South of Scotland.

The remaining young eagle was returned safely to its nest. This particular pair of golden eagles within WildLand Cairngorms have been very productive in recent years - they have hatched twins for four consecutive years. While we believe it may be a loss to us here at WildLand, however, the donation of this young eagle to the South of Scotland Project and the wider collaboration it has brought has been very beneficial. We look forward to hearing how this young bird fairs.

If you look closely at this photo there's an interesting observation to be made - you can see the eagle's right eye is a different colour. This is due to the eagle's nictitating membrane! The nictitating membrane acts as a third transparent eyelid that raptors and some animals have to protect their eyes. This membrane opens and closes to moisten the eye without them losing vision. Perfect for a predator such as an eagle!