Tuesday, 11 October 2016

Verreaux's eagle ranging behaviour

We caught and GPS tagged the first Verreaux’s eagle for this project back in 2012. It was a breakthrough at the time and watching the first data download onto our base station filled me with excitement for what we would find out.

Here it is. Our first paper “Ranging behaviour of Verreaux’s eagles during the pre-breeding period determined through the use of high temporal resolution tracking”, published by PlosOne today. PlosOne is an open access journal, meaning it is free for anyone to click on the link and download the paper.

One of the great surprises for me was the relatively small home range that these eagles maintained. Considering the inter-nest distances, these small home ranges are expected. But considering the wingspan and soaring abilities of these birds the optimistic dreamer in me had expected soaring over vast expanses. Another surprise was the lack of any obvious difference in the distance and duration of trips away from the nest between the eagles in the natural Cederberg area and those in the agriculturally transformed Sandveld area. Verreaux’s eagles in the Sandveld were also found to be selecting for near-natural and degraded habitats over natural or fully transformed habitats, suggesting that eagles benefitted from some of the agricultural development in this region.

Although this paper is based on a small sample size of eagles, it is the first of it’s kind using high-resolution GPS tracking technology. I am extremely grateful to the UvA-BiTS team for their dedication to developing these tags and I look forward to continuing to use them in our future research on Verreaux’s eagles.

Thursday, 11 February 2016

Eagles and agriculture coexist

The first scientific peer-reviewed paper coming from research by the Black Eagle Project has been released. Here's what its all about:
To biologists’ surprise, an eagle population living in a South African landscape dominated by agriculture appears to be thriving, according to a new paper in The Condor: Ornithological Applications—even out-performing their neighbours in undeveloped mountain habitat.

Verreaux’s Eagles (Aquila verreauxii), an apex predator in southern Africa, are in decline, and Megan Murgatroyd of the University of Cape Town and her colleagues wanted to determine if habitat loss due to intensifying agriculture could be the culprit. Instead, when they compared the breeding productivity of eagles in South Africa’s heavily farmed Sandveld region to that of the smaller population of eagles in the nearby Cederberg Mountains, they found that the Sandveld population’s breeding success was actually the highest of any Verreaux’s Eagle population ever studied.

Mugatroyd and her co-authors speculate that the eagles’ prey base could be more available and diverse in the Sandveld, and that the gentler terrain could take less energy to navigate. However, the researchers caution that there may be a threshold of agricultural transformation beyond which the Sandveld region’s population would begin to struggle. They recommend that management in the Sandveld region should focus on identifying and eliminating any potential sources of eagle mortality, such as wind energy development.
Murgatroyd and her colleagues monitored eagle nest sites in the two areas over four years, visiting them every two to three weeks during the breeding season. “It has been a huge privilege to undertake fieldwork in this part of South Africa,” says Murgatroyd. “The Cederberg is a beautiful natural wilderness area, so we were surprised when it became apparent that the Verreaux’s Eagles breeding there are far less productive than those in the Sandveld, which has been extensively converted for agriculture since the 1980s. This comparison has highlighted the potential importance of an agricultural landscape to Verreaux’s Eagles, but further research, in particular with a focus on adult and subadult survival rates, is still needed for a better understanding of the long-term persistence of these populations.”
The influence of agricultural transformation on the breeding performance of a top predator: Verreaux’s Eagles in contrasting land-use areas is available at:
About the journal: The Condor: Ornithological Applications is a peer-reviewed, international journal of ornithology. It began in 1899 as the journal of the Cooper Ornithological Club, a group of ornithologists in California that became the Cooper Ornithological Society.

Tuesday, 2 December 2014

The Sunday Times

The Black Eagle Project features in the Sunday Times, 16th November 2014. 
Article by Claire Keeton.

And a big thank you for sponsorship and and support: 

Monday, 3 November 2014

Diary of a black eagle researcher

I want to share the experience and feeling of a couple of extraordinary days ‘working’ in the Cederberg.
At 7.45h in the morning I leave my car to visit a nest and walk on to a hut where I have planned to spend the night. Around 9.00h I arrive at the nest to do observations. Due to the sun rising above the nest cliff, I’m forced to search for a new observation spot where the sun doesn’t blind me. After approximately 6 hours of observing I take off in the direction of the hut. I realize that it will be dark around 18.15h and I am not sure how long the walk to the hut will be. From the observation spot I go off trail to take the shortest route to the hut. This means that I have to go up pretty steep, climbing rocks and struggling through bushes. From my map I can’t define what the inclination is, my heart rate, on the other hand, does show a steady increase. With a backpack of approximately 10 kg on my back I realize that the climb is pretty tiring. Not every boulder I climb on it is clearly visible how to get on, but that’s what hiking uphill off trail in the Cederberg is all about. Halfway up the slope I want to pull myself up a rock. I place my hand and pull to see if I it is steady enough. A disc of rock slides down and a big black scorpion appears. It was hidden under the disc. I remember this species from earlier hikes but this one is three times as big as the last one I saw. I assume that it rather sees me taking another route. At 17:30h I arrive at the hut. A stream close by is a fresh water supply. With the most beautiful sunset in the background I have had so far, I warm up my food and settle in the hut. I go to bed early realizing that tomorrow will be a long day full of hiking and two nest visits scheduled.
I have a decent breakfast because I don’t like pausing during hiking. At 8.30h I leave my sleeping place, off to the first nest. Luckily a trail leads me to the first nest and on my way I find a new nest. Even Megan has never seen this one. Unfortunately, I don’t see any signs of activity on or around the nest. I move on to the nest that I was heading for. At this spot I am lucky to spot the eagles within 10 minutes. Unfortunately, not on the nest. After watching them for a while I lose them. One of them was on the nest for a minute but didn’t seem to incubate anything. It did not come back to the nest so I assume they are not incubating. I head on to the next site. The first 15 minutes is back on the same trail, the other hour and a half are in, for me, an unknown part of the Cederberg. If I would follow the path to the nest it would take me more than a day to reach the nest. The first part off trail has a nice inclination. It is next to a small stream which supplies me with fresh water. At the source of the stream it flattens out, but with huge boulders. I assume that not many people have been up here. It is rough up here and there are ginormous boulders to climb on. At 15.00h I arrive at my observation spot. Now I am facing the nest cliff from a better angle (higher up). Unfortunately no breeding activity but two black eagles flying around the nest cliff. Meaning that the territory is still occupied. At 16:30h I finish my chocolate and my observations and leave the eagles perched. 
I realize that I have one hour and 45 minutes before it gets dark. Hopefully, I am back on track by then because I had not planned to spend another night out. After walking for a while on a plain on top of a mountain, I start feeling my backpack. I orientate on the mountains to see what my options are to get back down. The sun sets at 17.45h and I realize I don’t have much time before it gets dark. I think it will be tough to get back today. I think by myself: “I will keep walking, I don’t want to spend another night out.”  I go up one side hoping that I can get down on the other side. When I am on top it is dark. Luckily the rocks I walk on are mostly white. When I arrive on the other side of the mountain at 18:45h it is dark and I can see 50 meters straight down. That was not what I had hoped to see. In this darkness I have no clue how to get to the path now and I don’t want to climb back up in the dark. I search for a sleeping spot without being picky and take the first spot with a small overhang. Although it is on hard rock and close the edge, it will be fine for one night. I hope I don’t move in my sleep, however on this rock I will probably wake up when I start moving. I send out a message that I am out for another night to the people who may expect me back on Driehoek. On 19.15h I get in my sleeping bag realizing that it will take twelve hours before the sun rises. That is long if you are lying on rock as hard as concrete. I can’t find the good position, which I probably won’t find. Although I am constantly curious how close I am to sunrise during the night, I only check my phone twice for the time. Once at 1.30h in the morning, just halfway through the night, and the other time at 6.30 in the morning. In the morning light I can see how far down it goes. Far! But I do see the path I was looking for. That is a good sign although this route is no option without climbing equipment. At 7.30 I leave my sleeping place and go on to another place where I, hopefully, can go down. Again I am unlucky. I go back up and feel trapped on top. I check the map and find another spot to go down to the path I am aiming for. My next option is suitable for going down. At 9.20h I reach the path which leads me back to my car. At 11.00h I am home sweet home. I lost some energy but I gained some knowledge about myself, the eagles and the Cederberg.
~Steven Karel Bekker

Wednesday, 25 June 2014

The Love for the Eagles

Wow. I get excited every time I see one. Even more when I see two. Whether it’s with the naked eye, through the binoculars or through the telescope. All sightings are amazing. Their movements in the air express full control. When they display behaviour to defend or define their territory they make steep dives and climb again to make a looping to go back for a dive. Undulating or pendulum flight is what this behaviour is called.
Last time, I was lucky to see the eagles soar in front of and above the moving moon (see picture). To see that the Eagles have a larger wingspan than the diameter of the moon was amazing. This was a moment where I thought: “Although I don’t have the best camera to get this on a photo, this picture will be on burned on my retina for the rest of my life”. Well, you can have worse things burned on your retina. They seem to chill on the thermals and soar a bit through their territory. Why not? If I could soar I would be soaring all day. The more time I spend here in the mountains, the more I think I was born in the wrong country (without mountains) and born in the wrong nest (without wings). Probably my ancestors took the wrong turn tens or even hundreds of million years ago. You would have amazing eyesight and probably see cape leopards weekly. And the views from high up in the air. Wow that must be amazing. When you’re not on your nest, incubating or caring for your chick, you’re searching for Dassies in the Cederberg or Molerats, Helmeted guineafowl and Angulate tortoises in the Sandveld. I would rather live in the Cederberg, because there are more mountains and less annoying pied crows. I’ve seen some chases between pied crows and the eagles. Sometimes the eagles were being chased and sometimes the eagles chased the crows.  Although they fly as if they´re in full control, their walking appears to be clumsy. They walk like criminals. With their head a bit down as if they are hiding something.

Dreams and more
I have even had my first dream about eagles. It took me approximately two weeks of observations. It was a nice dream where I had 3 eagles in view, but I wasn´t sure if the third was a juvenile or another species. I was warned that I would get hooked to the eagles, but I am not afraid of getting hooked. I am an easy victim, because I think I am pretty close to that state. Keeping in mind that I haven´t even seen a chick yet and I not even half way through my fieldwork. During my fieldwork I find myself sexing the eagles when I see one. When one is on the nest I think: “She’s on the nest”. And when I see one flying I think: “He’s flying”. This is unintentional and I don’t know how to get rid of this thought. But as long as I don’t write it in my notebook it doesn’t do any harm.
Next blog will be about how an eagle observer spends his Sundays in the Cederberg.
-Steven Karel Bekker

Monday, 9 June 2014

My first few weeks going solo!

Here I am, sitting behind my desk. Locked in my 15m2 hut with the rain pouring down on my roof and the wind desperately trying to get in. I can hear it knocking but I am not answering. With only Jack Johnson singing his songs. Can´t you see that it´s just raining, ain´t no need to go outside. After two and a half weeks of solo trips I have felt snow, rain, clouds and have seen a lot of rainbows, sun and, of course, Black eagles. And lots of mountains with beautiful views and impressive rock formations, formed by wind, water and frost.
In my days in the Spanish Pyrenees I read somewhere. Happiness is only real when shared. Well, that doesn’t count for me. “My” eagles give me so many air shows and joyful moments (more on this later). And the views here!!.. From certain spots you can see for many miles (hard to estimate how far). These views give me goose bumps. I realize what I miss in the Netherlands. And not to forget the rainbows. Every time I try to approach them to look for the pot of gold they “ jump” to the next mountain. But one day. I love it!!
During my last 3 weeks of fieldwork, not to forget that I am actually working here, I have visited 16 nests in 7 days in the Sandveld. In this area, I drive from one nest to the other to check their stage of breeding. At this stage I hope to find them incubating. Some of them have started and others look promising and spend a lot of time around or on the nest. The pairs that are incubating spend much time on the nest and regularly swap. In the Cederberg, on the other hand, I have to hike for hours to the nests where access is much more difficult. Here they have nests in more remote places and I spend a lot of time hiking to a good spot to set up my telescope and start my observations. Here I have visited 12 nests so far. Like the Sandveld, here the first pairs have initiated incubation. During my hikes I am thrilled by the views and rock surrounding me. I force myself to stop every now and then to “feel” the mountains, or to admire the baboons which let me know of their presence by their impressive barking. They don’t seem to be impressed by my barks. Luckily I have 5 months to impress them. Or klipspringers which are checking me out from a rock and react to my whistles by facing me directly. Most of the times they are in groups of three. After a while they move on and hop up the rocks with the greatest ease. Also the sightings of Rock Hyrax or Dassies become more common. Sunbathing on rocks they make their alarm calls. I think there are not many animals living in the Cederberg which I see before they see me.
But the Cederberg Mountains bring me strong winds, snow and low temperatures as well. And the winter hasn’t even started yet. I am curious what the real winter has to offer. I have learned that bad weather doesn’t exist. But bad clothing does. Thus a good preparation for a cold day is important because three hours of not moving with the wind in the face with a vibrating telescope is tiring. A cloud that comes by and blocks my view on the nest is most frustrating and leaves me cold. And the rain filling the rivers which influence my thoughts of whether my bakkie can get through. But the advice I got from Dawie was. “You just try and learn by experience when the waterlevel is too high. This means that I just give it a go until I get stuck. Why not? We’ll see where or when the ship beaches. So far I haven’t had any problems.
Yesterday I had my first sightings of humans in the field. The first pair consisted of two males and the other a male and female. Both pairs didn’t show any signs of incubation. And both were far outside of their territory, but I did not feel threatened. After my two weeks in the Cederberg I have taken a look at my data on primate abundance. My preliminary results suggest that the most abundant primate is the Chacma Baboon (Papio ursinus) followed by humans (Homo sapiens). I have to be cautious because I don’t have any statistical results to support these thoughts. First I have to collect more data to confirm my suggestions (More on this later) .
And the Eagles. The Verreaux’s Eagle or Black Eagle. With their ginormous wingspan of 2 meters. A flying door. Bigger than my wingspan. The one moment they are checking out part of their territory from a perch or their nest. The next they are in a thermal with warm rising air to gain height without spending energy. The ease with which they glide through the air. Jealous? Yes! And they probably see better than me even without a telescope. Magical. I want to know how their eyes work. I feel fortunate to spend my time watching these powerful raptors in this wonderful place.
~ Steven Karel Bekker

Thursday, 22 May 2014

Eye to eye with a Cape Leopard

Two weeks ago Steven Bekker arrived in South Africa to join me with field work for the Black Eagle Project and to work towards his own MSc. All the way from the very flat Netherlands, I am sure he has had many new experiences, but somewhere amongst the eagles and the mountains, this was a real welcome to the special secrets of the Cederberg. In his own words, here's Stevens first blog "Eye to eye with a Cape Leopard".
Steven at work!
On a cold Tuesday evening at Driehoek, I am sitting with Dawie, Lizette, Karli and Megan in their living room on Driehoek. We’re watching TV after a lovely night out at Oasis for their legendary ribs. Around half past nine Megan and Lizette go to bed and Dawie and I stay to watch National Geographic. In the next break I feel sleepy and tell Dawie that I am going to bed. The previous nights I went to my hut without light and I had only the light of the moon to guide me home. From their house it is easy to find my way to the corner of the garden and reach the gate, but after the gate the dark path to the campsite through dense undergrowth and trees is hard to find. But every night I managed to find my way home. Tonight Dawie offers me a flashlight. I gratefully accept the offer to have some light on my way home. I leave the house and disappear into the night. On my way to the gate only about five meters from the house I stop. Two eyes light up in the light of my flashlight. I wait and see that there is something lying on the ground approximately 15 meters from me. It gets up and turns to walk off calmly through the gate and walks part of my path through the woods. I realize that I’ve just seen something special but I don’t quite know on what level. I turn around and walk back to the house. I get in and ask Dawie: How can I tell the difference between a Caracal and a Cape Leopard because I just saw a cat. Dawie jumps up and walks with me to the place where I saw it and we follow the path that the for me unfamiliar feline has followed. At that moment I think we are not going to find it. Dawie asks what the size was. I show him the height of the animal and he replies: “That’s a leopard!”. Together we walk down the path and walk around the piece of forest to arrive at the other side on a more open space. Dawie sees on the other side of a small river approximately 50 meters away two eyes light up. 
He whispers: “it’s an owl”. But he is in doubt and we wait. The eyes move and when Dawie imitates the sound of an orphaned lamb, the “owl” starts moving. “It’s not an owl. It’s a leopard” whispers Dawie and he attracts/lures the leopard towards us with his lamb cry. After a while the leopard seats itself on a rock less than 30 meters away from us. He seems chilled and Dawie says: “I will fetch my camera”. Thrilled from the adrenalin I stay behind with the light from the flashlight with a leopard, for me, a very short distance away. When Dawie is gone I hear something in the bushes next to me. It’s nothing. The leopard starts moving again. This time away from us and disappears into the night. My lamb imitation is unfortunately not as good as Dawie’s. When Dawie returns I point him where I saw the leopard for the last time. We walk around some bushes to get another angle onto the place where I have seen him for the last time. When Dawie starts imitating the lamb again, after a while we see a pair of eyes again. “There he is!” we whisper enthusiastically. And we walk back to the first spot to get a better view. He reacts strongly on the luring sounds and comes closer. Dawie takes pictures but because of the limited available light it is very hard to get a good picture.
When he is on the edge of the river and seems to make a jump towards our side. He doesn’t, but instead he walks off on a path towards a fallen tree to cross the river. At that moment Megan joins us after searching for us in the dark when Dawie told her that I had seen my first leopard. The leopard has crossed the river and is now less than 20 meters away from us in the bushes. There we are waiting for a leopard to come out of the bushes. I realize that I have no clue what Dawie’s plans are when he appears from the bushes, but he keeps imitating the lamb. I am holding the flashlight and on the moment of truth the light is gone. It does not fade it goes dead in less than a second. Total darkness. I think we lost our advantage. Dawie whispers: “Back off, slowly.”. After a while Megan can make a little bit of light with her camera. We walk back to the house to charge the light and get other lights. We take a breath from our adventure and I think it’s over. We won’t find it again. With smaller lights we’re off to search for it again. After searching in a couple of places, Dawie climbs a rock to get a better view and with his light he searches for the two eyes. He whispers and points: “There it is again.”. He is back on the other side of the river. We go to the other side of the river to search for it and cross the river in the dark via another tree. Dawie is in no time on the other side of the river. For me it’s harder to get to the other side and Megan behind me is also relieved when she reaches the other side dry. From there we slide onto a path and climb a couple of boulders. On approximately 30 meters the leopard sits calmly on a rock. As soon as he notices us he slides off the rock and hides behind one. Megan tries to make pictures and although there is almost no light Dawie still knows where he is. 
It is hard to follow its movements. When Dawie makes calls again it creeps towards us. He whispers: “it is curious of what we are.”. Only somewhat like 20 meters away it stops and watches us.  After approximately 10 minutes it turns and walks away. He does turn its head when Dawie makes his calls but the leopard walks off gently. Dawie steps of the rock and continues onto the path to find him again on the other side. Megan and I follow. We stop on approximately 30 meters off where we’ve seen it for the last time and Dawie starts making its calls. We have no clue where the leopard is and Dawie wants to attract it. It could be hidden right behind a rock less than five meters away from us but Dawie wants to lure him towards us. Megan and I whisper that it’s perhaps not the best idea to attract him when we have no idea where it is. Dawie: “Yes, lets get back” and we walk back to the house. Back in the house we take the time to take a breath. Dawie gets his rifle to deter the leopard from the livestock with a loud warning into the night sky. Their Anatolian Sheep dog recently passed away, who would usually protect the livestock, and now there are lambs on the farm. Therefore, a loud bang was needed to send him back into the veld. Because I spotted the leopard I get the honour of shooting the rifle. This way my first shot ever!! After talking for a while I go back to my hut on the same path through the trees. I walk on this path with a different feeling. In bed I relived the overwhelming experience of what I’ve seen tonight. My first Cape Leopard. Not bad for my first week in the Cederberg Mountains!!
-Steven Karel Bekker