Across the African Savannahs many different birds can be seen strutting around on long legs, a perfect adaptation, often coupled with long necks, to give them a higher vantage point to see over the long grasses. We are talking about ostrich, korhaan, ground hornbill and storks to name a few. All these birds use the same method of steadily walking through the grass picking of preferred prey items; grass itself in the case of the ostrich.
One of the most fascinating to me is the secretarybird (Sagittarius serpentarius). Reportedly named for its resemblance to a medieval scribe with a quill behind his ear other sources suggest the name is a Francophile corruption of the Arab word saqr et-tair which translates to hunter-bird. Whatever the origins of its name the frond of spatulate nape feathers and the elongated central tail feathers easily distinguish this bird.
It is something of an enigma taxonomically speaking, making up its own unique family, Sagittariidae. It seems secretarybirds are related to eagles sharing skull structure and a type of feather lice. Currently aligned to diurnal birds of prey it has previously been thought of as a relative of storks and cranes. Indeed its breeding behaviour is very similar to that of storks, which to make things more complicated are also share a close affinity to birds of prey.
Taxonomic complexities aside secretarybirds do look like elongated hawks, they share that hooked bill and yellow cere common in birds of prey, they also possess a large gape which allows them to open the bill wide enough to swallow large prey whole. But it’s their feet that do all the work.
The modus operandi for a secretary bird is to stalk along quietly and stomp its prey with a torrent of fast powerful kicks to dispatch it. This method is used for a number of prey items such as arthropods, rodents, amphibians, game birds even mongooses. In fact anything, really, that can be subdued and killed by its deadly kicks is fair game. That said it is the secretarybird’s ability to despatch snakes that has endeared it to most Africans.
To sneak up on a snake and then kill it quickly takes a lot of skill and you best not make a mistake otherwise in the African bush you may end up the one dying.
A study led by Dr. Steven Portugal, from Royal Holloway, University of London found that although other birds of prey strike their prey with far more force this is enhanced by the momentum of their entire bodies plunging down from flight. The secretarybird is able to exert a force 5 times greater than its own body weight from standstill and can repeat this accurately with multiple kicks being delivered at a speed of 15 milliseconds each. Fast and furious, that’s how this bird tackles deadly snakes and biting mongoose.
If you are interested you can read the paper here. http://www.sciencedirect.com/science/article/pii/S0960982215014839
June through August is a busy time for scientific researchers. They get to leave their desks and all that computer stuff and go visit their study area. Snapshot Serengeti’s resident researcher Meredith is lucky enough to be in the Serengeti as I write and she has shared a few recent experiences with me.
She is currently setting up a new camera-trap array in Grumeti Reserve which borders the Serengeti National Park in the north west. This area was created as a buffer zone to the Serengeti National Park to help protect the western corridors of the famous wildebeest migration of the Serengeti/Mara ecosystem. Grumeti in turn is bordered by villages and has one of the fastest growing human populations around the Serengeti Park. Traditionally these communities hunted for bushmeat to supplement their diets but with the rise in population it is doubtful if this is still sustainable.
Meredith has been out this week following the migration as it moves along Grumeti’s northern border. As well as setting camera-traps and marvelling at the numbers of wildebeest she has also seen the darker side of conservation that almost anyone working in protected wildlife areas in Africa is familiar with; poaching. She reports that they have been removing snares daily and that distressingly they found 4 snared wildebeest within a half hour, two were dead, one had a broken leg and had to be killed but miraculously they were able to release one. Whilst trying to select camera-trap spots Meredith and her team encountered poachers butchering a fresh caught wildebeest, they were able to give chase, alas to no avail.
In areas like this the locals know well the movements of the animals and they will seed the area with thousands of wire snares. Anti poaching teams are kept even busier during migration time knowing this too. The anti poaching team, well trained as they are, have had more luck than Meredith and her team. This week they set up an ambush and took out a biltong (dried meat) camp. Their efforts on the front line destroying snares and apprehending poachers as well as the community liaison work that goes on at Grumeti has reaped rewards. Animal numbers are on the rise, the elephant population has quadrupled in the last 11 years and giraffe and topi numbers have tripled.
Still Dr Craig Packer and his colleagues have estimated that tens of thousands of wildebeest are poached each year…and this is not a problem that will go away. You can read more about the issue in this Africa Geographic article.
Poaching goes on all around the world, I have even found wire snares set in my own garden her in France (probably for badger). It is a senseless, lazy but effective way to catch animals. There are many reasons why people poach, when I lived in South Africa the local community would poach our animals not because they were poor and couldn’t afford meat but because warthog and impala meat could fetch higher prices than chicken, goat or pig. Christmas was a particularly bad time for poaching as local chiefs put in their orders. Bushmeat was a delicacy and poaching made good money. In Central African Republic the systematic stripping of wildlife by the Sudanese cattle herders has been stimulated by draught and poverty in Sudan, they dry most of the meat to take back and sell in the Darfur region. Utilising the natural world is deeply rooted in many cultures around the world and always has been. Opportunity is what fuels the practice but it is the rapidly rising human population that is causing this age old practice to become unsustainable in our shrinking world.
I hope Meredith doesn’t have to witness too much more wildlife destruction but all the same it is good for a scientist to get firsthand experience of one of the biggest issues facing wildlife today and for us to recognise it.
As some of you know, Snapshot Serengeti is not just about mammals. Their avian cousins also like to get in on the act especially the larger ones. Amongst the more common captures are kori bustards, secretary birds, korhaans, and storks. The one I like best though is the ground hornbill.
I fell in love with these birds many years ago when I helped hand raise southern ground hornbill chicks. Although wide spread and fairly common over most of southern and eastern Africa the southern ground hornbill has lost around 70% of its home range in South Africa. They are large birds and don’t do well outside of protected areas especially where human density is high.
Ground hornbills lay two eggs in, believe it or not, a cavity in a tree. The first chick to hatch will kill the second, which is really just an insurance policy in case the first egg doesn’t hatch or should die in the first few days. We were given permission to take the second egg once the first had hatched in order to hand rear then release the birds. The newly hatched chick has to be one of the ugliest babies I have seen. It is a charcoal grey naked greasy looking blob with a head so large it cannot lift it up. For the first day or so it just flops around barely able to raise its bill for food. When its feathers start growing it looks like a diminutive dinosaur. Eventually they do blossom into the splendid giants that strut across the savannahs in small family groups eating a range of food stuffs from insects, rodents and reptiles. They can kill efficiently with that heavy bill and will take anything up to the size of a hare.
Considering their size it is hard to believe that they can fly but fly they do and spend time perched in trees. In fact the loss of large trees is another reason behind their decline, as I said earlier they need trees to nest in. Ground hornbills are cooperative breeders with several family members helping to rear the single chick. This joint effort seems strange until you realise that although they breed once every three years the groups only manage to raise one chick to maturity every 8 to ten years. Once a chick has fledged it is dependent on its parents for two years, which is the longest span of any bird and makes reintroduction programs very hard. It only reaches maturity at 6 years old.
There are two species of ground hornbill, found only in Africa. The southern ground hornbill (Bucorvus leadbeateri) the species found in the Serengeti and the northern ground hornbill (Bucorvus abyssinicus) found across sub-Sahara from Mauritania to Uganda in suitable savannah habitat. The later is slightly smaller than the former and has some blue facial patches which distinguish it from the red of southern ground hornbills.
Such a large bird living mostly on the ground the ground hornbills have not escaped the attention of man. Although many tribes hold totemic beliefs about the birds that afford them some protection others are not so lucky. The Zulus and Xhosa of South Africa believe that to break a drought a dead ground hornbill must be tied down in a streambed to attract rainwater. In a more modern twist ground hornbills, ever territorial will smash windows and car windscreens with their powerful bills in a misguided attempt to evict intruders (namely their reflections) This has not endeared them to humans.
All in all the ground hornbills are magnificent birds, next time you spot one on Snapshot Serengeti take a moment to have a closer look.
The 5th of June is world environment day. This event was created by the United Nations back in 1974 to promote awareness of our environment and to spur people globally to help protect it. Its celebration has never been more important than in today’s challenging times. All over the world people will be taking part in a host of events that celebrate our environment. Some have formed clean up events of local beaches or city parks. Others will be doing a bioblitz in their gardens or local reserves many will include children who will be inspired by searching out and identifying bugs. There will be events organised on the public scale such as awareness marches or environmental film screenings. Some folks will simply celebrate by stepping out in the open air to take a walk or picnic. Whatever the event you can be sure that a lot of people will be considering the environment this week and that can never be a bad thing.
Each year there is a theme, this year it is ‘connecting people to nature’ I thought this was particularly apt for us citizen scientists at Snapshot Serengeti. Through the millions of images we classify there is a strong connection to the rhythms of animals in the Serengeti. We get to appreciate the wide biodiversity of this immense ecosystem and for those of us unable to visit such a place it is a way to connect to a wild unspoilt place. It is a way to visit, virtually, leaving no carbon foot print as we would by flying there. I feel it is a privilege afforded us thanks to technology that I would not have even dreamed of 15 years ago.
Snapshot Serengeti is the perfect antidote to the doom and gloom decried each day by the newspapers. In a world where wildlife is dwindling and the finger is firmly pointed at us as the major cause of climate change Snapshot Serengeti feels like something positive and good. Something to give us hope that we might not have wrecked everything just yet. From our armchairs we not only experience the wonders of nature but at the same time we are actually benefiting science with our classifications. What can be better than that?
So if you have nothing else planned this #World Environment day why not jump on to Snapshot Serengeti and get classifying, better still see if you can recruit new classifiers, the more the merrier.
If you want to read more about world environment day visit this site.
The waterbuck just stood there, unfocused, staring at nothing. He didn’t move except for the gentle flare of nostrils and rise of ribs as he drew breath. About 8 to 10 minutes went by and still not even a twitch of an ear to dislodge an annoying fly. Then as if released from a spell his drooping head rose a little and he took a step or two towards the stone bird bath where he took a few long draughts of water. After that he slowly walked of through the bushes and out of sight.
I couldn’t quite understand his behaviour thinking perhaps that he was ill. Although he sported a magnificent set of horns his coat looked more than a little out of condition and he looked thin. For a waterbuck to be this close to the house in the middle of the day was unusual. He was less than a meter from me; if the glass window wasn’t there I could have reached out and touched him. I didn’t see him again after that encounter until about 5 days later. Sitting on my stoop I could smell a whiff of something dead, not an unusual smell when you live in the bush, so I went exploring following my nose. It didn’t take long to find him. He was tucked in, sitting down, between the banking and a large boulder. First I thought he had fallen but actually he looked so peaceful I think he lay down in a position that he felt protected in and let his life ebb away.
You see on closer inspection I found his teeth to be worn away to almost nothing. This is common in antelope, if they make it through life without being preyed upon or succumbing to disease then they often die from starvation when the teeth, worn down to nubs, are unable to cope with the tough vegetation it survives on through the dry season. That vacant stare I had seen is something I have witnessed in starving antelope before. So although I couldn’t rule out disease (I am no medical expert) my guess from his behaviour and condition was that he had passed away with old age.
My quandary now was what to do with him. I could leave him be and let nature take its decomposing course (and this is what I would normally do) but that would mean I was going to live with an ever more nauseating death smell for a few weeks which believe me is not good. On the other hand pulling a 200kg animal out from a snug hole was not going to be easy. To cut a long story short I called for backup and with ropes and much holding of noses we got the waterbuck out and dragged him down to the river side. I sat there all day waiting to see if a croc would come and take the waterbuck or perhaps a hyena or vulture. Disappointed that none of natures garbage collectors came I walked off home just before dark.
First light the next day off I went back to the scene. Nothing. Not even a drop of blood. I can only conclude that the crocs did indeed come under the cover of dark and dragged the carcass into the depths where nature’s great cycle of life and death continued to the crocs advantage.