Goldie Rings

Golden Eagles are now in the peak of their breeding season and over the past few weeks I've been visiting nests with my Scottish pals to ring the chicks, most of which are 4-6 weeks old. It has been brilliant to return to some familiar territories from my 2014 trip and see which sites the birds have chosen to nest in this year.

While a typical goldie nest is located on a cliff ledge, about 5% of the 440 breeding pairs in Scotland build their nests in tall trees, most of which are ancient and majestic Scots Pines (Pinus silvestris). Such nests, which consist of a mass of dead branches, heather and sprigs of pine and Birch (Betula pendula), are set near the top of the tree in a crown of wonderful, spreading, sturdy limbs. These provide good footholds and make working at the nests quite easy. Ewan Weston and I scaled to the nest shown above to weigh, measure and ring the single chick present, which was about 5-weeks old. As you can see, there was plenty of room in the canopy for both of us!

Even as chicks, Golden Eagles have large yellow feet. This eyrie reared 'twins' in 2014.

Two other tree-nesting pairs of eagles had also reared single chicks, but these were at locations where the nests were much higher and less accessible (even to barefoot free-climbers!), so we did the processing on the ground. At each site, after Ewan had climbed to reach the chick and lower it down in a handling bag, I helped Jenny Weston fit the rings while she showed me how to take measurements to accurately determine its sex. Jenny is a highly experienced bird handler and I was very fortunate to be able to watch her work and learn from her expertise.

A 6-week old eaglet in the heather. Its bright yellow cere is a sign of good health.

Stainless-steel leg-rings are fitted using special pliers. Eagle feet make even large human hands look tiny!

A rivet-gun is used to secure the aluminium colour-ring in place on the bird's left leg.

The metal colour-ring being fitted above is used to increase the chance of the bird being resighted at a later date, as the stainless-steel rings are not as easy to discern. Black has been chosen because a great deal of highland monitoring is being done with infra-red, motion-sensing cameras, which take black-and-white photos that clearly show the number. This ring appears tight, but the thick leg-feathers give the false impression it is closing on the leg when it is actually loose-fitting around the skin. Eaglet legs actually decrease slightly in diameter as they approach fledging because of the reduction in 'blood feathers' that are highly concentrated during development.

Even at this age, it is normally possible to tell by eye whether the bird is a male or a female, the latter sex being larger overall and having noticeably bigger feet. Ewan has found that the footspan, measured from the tip of the hind toe to the tip of the middle toe (with the foot spread open), is the most accurate way of sexing eaglets. Other measurements taken include the head, bill and wing lengths, and the size of the hind claw, as shown below:

This rear talon is a formidable weapon and care must be taken to ensure the eaglets don't do any damage to our soft hands! Eaglets have not yet had the opportunity to wear their talons down by grasping prey or perching on solid branches, so the tips are pin-sharp! When these birds fledge, this 'finger-dagger' will be close to 50 mm (2 inches) in length and used as the primary weapon to deliver fatal blows to a range of moorland vertebrates. While an adult goldie could easily drive a talon through a person's hand, their chicks are usually very placid and do not attempt to hurt you; they do not really yet know how to use their equipment! Instead, they sit quietly in the heather and lay flat, a natural instinct to hide from potential predators as they pass by.

After processing is complete, the eaglets are promptly returned to their nest. At this stage of the nesting period, the adult eagles are usually away hunting for much of the day, so visiting nests to conduct this research causes minimal disturbance to the birds. Eagle eyes may be watching, but with the extreme efficiency and excellent bird-handling skills of those involved, we are in and out in a flash and the birds can carry on as normal.

In preparation to return an eaglet to its eyrie, Ewan hoists the handling bag back into the canopy.

One particular nest in the northern highlands was set in some of the most spectacular scenery I've ever seen - remote, rugged country with deep gorges and ancient cliffs, adorned with heather, moss, ferns and occasional Rowan (Sorbus sp.) trees. This is a classic example of the habitat in which most of the Golden Eagle population lives, and it is both exhausting and exhilarating to traverse on foot. An 8-hour round hike took Stuart Rae, Adam Ritchie, his brother William and I to the nest cliff, which we were able to peer across to over a small gully.

This eagle eyrie (centre left) has been built between an emergent Rowan tree and the ancient granite gneiss cliff.

At first glance it was quite difficult to spot the eyrie, but when an eaglet's downy-white body moved, it instantly gave the location away. The chick was about a month old, the perfect age for ringing. While William stayed to take photos, Stuart, Adam and I zigzagged our way up the nearer hill, and traversed across the ridge until we were above the nest. I was very lucky to be offered the opportunity to descend to the nest and ring the chick, so I left my bag in the heather, put on my harness, attached myself to a climbing rope, and eagerly clambered past tufts of heather and gripped the bare rock on my journey down towards the nest.

The month-old eaglet with fresh prey of Hooded Crow and Red Grouse on its eyrie.

This was the first active cliff-eyrie I had been to in Scotland, and it was so interesting to take note of the difference between it and the tree-nests I'd seen recently. This one had the most wonderful assortment of construction material - heather, birch, woodrush, rowan, dead grass - all arranged in a sort of 'haystack' formation, and the varied colours of this vegetation, together with the flecks of white eagle down-feathers stuck to the surface, made it appear as some kind of alpine art-work, a simply wonderful structure. Nature really does create some truly incredible scenes! And as Stuart mentioned in his recent blog post about this site, the eyrie was enormous! It's sheer size only became apparent when I was on it - I estimated it was over 2.5 m across.

You can view a few more images of the eaglet at this site on my Flickr photostream. Once the ringing and measuring was complete, I quickly ascended the cliff face again and we promptly collected our gear and left the site, as quietly as we had arrived.

It's been a privilege to be able to visit these eagle nests and learn first-hand how some of the most long-term and highly important ornithological work on Britain's largest raptor is done. The knowledge I've gained from the people mentioned here has been invaluable and I already know much it will help with my Wedge-tailed Eagle work back in Australia. Everyone has willingly shared expertise, stories and laughs, and this has made me feel so at home, and a small part of what is a great family. Thanks Scotland, for some amazing eagle days. I'm looking forward to more already!

I owe a great deal to Stuart Rae (centre), for first tempting me to Scotland, and fabulous friends of his like Adam Ritchie, another very knowledgeable ornithologist.

Greenbrae Visit

Today I had the privilege of volunteering a few hours to attend Greenbrae School (where a friend of mine Judy Duncan is a teacher) in Aberdeen, Scotland, to talk to a class about my work in Australia on Wedge-tailed Eagles. As always, I'm keen to grab any opportunity to hopefully deliver an inspiring message to a  group of young people about the importance of our fabulous environment, and spread the word about how a career in science can be super fun and very rewarding! I began the talk sharing my story of growing up in the Perth Hills and developing a love for the bush and its wildlife at a young age, then showed the children some pictures of what an 'eagle scientist' does, and linked things back to their homeland by sharing what I was doing in Scotland (assisting with research on the Golden Eagle), and how one day they might be able to do the same.

The highlight of the morning was being given such a warm welcome by a bunch of very surprised kids, who had seen Where Do Eagles Dare? only a few weeks prior, and who couldn't believe "the Austraaaaalian frum the teeeelly" was suddenly in their classroom!! After the talk and a wee bit of show and tell (I brought in some Golden Eagle feathers), I helped the class with an upcoming project they have been set on making short wildlife documentaries. We then crowded together for a photo and said 'EAGLES!!' with all the breath in our lungs!

Thank you so very much to Judy for inviting me in to meet and talk to her class, and for the lovely staff at Greenbrae for making me so welcome! I hope to visit again one day when I return to Aberdeen. For now, though, it's back to the hills for some more fieldwork :)

In the Highlands

 

I am very excited to be in Scotland where I'll be spending the next 5 weeks assisting ornithologists with their fieldwork, mostly on raptors. Today I had the pleasure of walking into the hills with my friend and fellow eagle enthusiast Ewan Weston, to check the status of a Golden Eagle (Aquila chrysaetos) site at which Ewan had observed a pair of eagles earlier in the season. Ewan recently completed his PhD on juvenile Golden Eagle dispersal using satellite telemetry, so it was wonderful to 'compare notes' with someone with whom I have so much in common.

Although it was summer, the landscape in Scotland is never short of water, and (coming from the driest inhabited continent on earth!) I found it very refreshing to see so much of it about. While walking along an old farm track, we discovered many puddles that were home to a number of Palmate Newts (Lissotriton helveticus), an amazing amphibian which was something totally new to me (the only amphibians I'm used to finding in Australia are frogs!). It was interesting to catch one and have a closer look at its very froggy face and lizard-like body!

Speaking of lizards - the weather was quite fine and the sun frequently broke through the clouds, leaving patches of sunlight warming up the heather. From a few of these we flushed many a Common Lizard (Zootoca vivipara). This animal is not something one always expects to find while out walking on the hills, as the air is often cold with quite a strong wind, but at ground level, grass and thick heather break up the moss-and-lichen covered open patches, and the lizards seemed to have no trouble clambering to suitable basking sites. On approach they would scurry into the tangle of heather to hide. Before it escaped in this fashion, Ewan managed to pick up one lizard and show me its spectacular orange belly. I also thrilled at seeing the coarse belly scales, and by contrast, the fine scales around the throat, legs and eyes.

Common Lizards are very camouflaged when seen from above, but have a beautiful bright belly.

A Common Lizard in profile - the brown eye stripe helps them blend in among heather stalks.

We left the track and climbed higher into the landscape, crossing many bogs and open patches of heather. The trickling burns (streams) were ideal places for another of the hills' cold-blooded creatures, the Common Frog (Rana temporaria). With the breeding season well underway, we encountered frogs of all different sizes. The one below was about as big as the end of my thumb.

Eventually, after crossing a beautifully wide glen, we reached the Golden Eagle site. Refreshing my memory from my last eagle-seeking visit to Scotland, I remembered how difficult it was to discover the nests of this species. Despite being the ecological equivalent to the Australian Wedge-tailed Eagle (Aquila audax), a bird whose nesting habits I am very familiar with, I found it fascinating to take note of the aspects of the Golden Eagle's ecology that were different. Most notably, 'goldies' usually nest on the ground, building their large eyries on flat, usually well-vegetated cliff ledges. Even when up close to a known nest cliff, the nest itself can be nearly impossible to spot, and one must keep a sharp eye out for bits of dead heather or tree branches used in its construction. The arrow in the image below points out the eyrie we visited, which was only about 4m above the ground near the base of the cliff. Ewan explained that this nest had been newly constructed this season, but he wasn't sure how far its owners had progressed with their breeding effort.

Golden Eagle eyries are almost invisible against the cliffs. This one is given away by only a small piece of overhanging heather.

 
We climbed up to have a closer look, which involved a quick scramble up a rocky but solid corner, and found the eagle nest to be empty. There were, however, plenty of flecks of eagle down-feathers on the nest, a sign the birds had visited it regularly, and a well-lined cup had been prepared for egg-laying.

Ewan explains this nest was well-lined but had no evidence of eggs being laid.

As well as the feathers, deep grooves cut into lengths of heather also told us the eyrie had been recently visited by eagles, and I pictured one tearing pieces from the moors with powerful thrusts of its sharp bill, then soaring in with the nesting material to alight on the ledge on which we sat. I've found the same bill-marks on sprigs of eucalypt and mulga on and below many Wedge-tail nests back home.

It was a shame to discover this eagle pair had not successfully bred, but the information was valuable nonetheless. It is not uncommon for large raptors like eagles to 'have a year off', particularly if they've reared a successful brood the previous season, are young and inexperienced birds, or if food supply is low.

We scrambled off the cliff and began the long walk home, stopping to look at crows and buzzards that zipped overhead. As our feet waded through a section of very dense heather, there was suddenly a flurry of wings and the grunts of a Red Grouse (Lagopus lagopus) filled the air. We noticed a hen grouse racing around with her wings folded down, conducting a 'wounded' display in an attempt to distract our attention away from her brood of small chicks, which scurried away through the grass.

You might like to see another photo I took of the grouse, as well as some of the other hillside scenes and characters, on my Flickr photostream here.

Willow and reeds line the banks of a wee burn, with a tall Rowan tree lit by the golden evening sun.

On the final stretch of our way home, we came across a sad sight: a ewe had died beside a burn, and her small lamb lay huddled next to its mother's smelly corpse. We failed in our attempts to catch the orphan, and ended up following it all the way down the hillside. Just as we gave up hope, the lamb decided to change direction and attempted to cross the burn, diving hooves-first into the gushing water. Ewan sprang into action and managed to catch it as it came up against the opposite embankment, which prevented the lamb's escape. He then placed it in his backpack and carried it all the way back to the nearest house. Fortunately, the residents knew where the farmer responsible for the lamb lived, and after a short drive up the road, we were met by some relieved folk who greeted the lamb with a warm blanket and a bottle of fresh, warm milk.

There's nothing like an animal rescue story with a happy ending to warm the heart at the end of a long day. Of course, had the eagle nest contained a chick, we might have found another use for the lamb...

Only joking, of course!!! ;-)