After my latest field trip to Namibia I was fortunate enough to spend a few weeks visiting some old haunts in South Africa. Even though I had very little time and no real scientific purpose other than curiosity I could not help but put out my camera traps whilst I was there. It was after all a nature reserve and surprises can happen.
One of the camera traps was located on a well used animal track that lead from the bush down to the river. The rains had not thus far been kind in that part of Africa and the bush was rather dry with little standing water so I was confident the track would offer some interesting images. As expected I had lots of images of vervet monkey, warthog, impala, nyala and waterbuck. Imagine my surprise then when I scrolled through 20 or so images of a small herd of waterbuck does with young to find this fluffy looking white thing that looked more like a sheep!
In fact it was a leucisitic waterbuck. Not to be confused with albinism, which is a condition caused by absence of melanin leading to pale skin, hair, feathers and eyes, leucism is defined as a partial loss of pigmentation that leads to an animal appearing pale or patchy but often with patterns still showing. The eyes in animals with leucism are normally coloured never the red that can occur in albinism. So albinism is a lack of melanin and leucism is a partial lack of melanin.
You can see this little waterbuck still has the distinctive bulls eye target ring around its rump that distinguish the common water buck from the Defassa waterbuck we are used to in the Serengeti proving it is leucistic not albino.
Regardless of which of the two conditions it has the young animal will have a tough time. The pale colour makes it stand out as a target to predators and it is thought that survival rates for leucistic animals are low. That’s not to say it won’t make it to adult hood, in fact the white lions of the Timbavati are a well followed case of leucism in a population that every now and then throws up a white cub or two, they are so well watched that it is known that some do survive into adult hood. From those few individuals stem most of the white lions that can be seen in captivity in zoos all be it showing all kinds of horrible traits of constant inbreeding.
After finding these images I was lucky enough to spot the herd with my own eyes. I watched the little leucistic waterbuck playing and frolicking with a like aged normal waterbuck and for all the world you wouldn’t know what all the fuss was about. The two were identical in every way except the pure chance of a mutated gene governing colour. Good luck to the pair of them.
Symbiotic relationships are common in the Serengeti. They fall into two main types, mutualism, whereby both partners benefit from one another and commensalism, whereby one partner benefits from the actions of the other but the other partner is largely unaffected or unharmed. I wrote recently of oxpeckers and large herbivores, large herbivores provide food in the form of ticks for the oxpeckers and oxpeckers provide a cleaning service for the large herbivores, a good example of mutualism. Birds such as cattle egrets that follow buffalo around to catch the invertebrates the buffalo disturb as they graze is an example of commensalism. Of course it is not just animals that have symbiotic relationships; my blog last week on termites and mushrooms was another example of mutualism.
So what about zebras and wildebeests? We see them all the time on Snapshot Serengeti in mixed herds, grazing peaceably with one another. Is this just coincidence or is this a form of symbiosis?
It is actually hard to say and of course that is why labelling things, especially behaviour is often tricky.
Zebra and wildebeest are both grazers meaning they mostly eat grasses but that doesn’t mean they share the same diet. They preferentially eat different parts of the plants that they consume. Zebras are quite content chewing longer tougher grasses where as wildebeest prefer shorter, more tender shoots. This partition of resources means they can quite happily graze side by side with out exerting pressure on each other.
Another good reason to team up is the extra safety that numbers provide. Not only do more ears and eyes provide better early warning systems but the odds of the individual being targeted by a predator are reduced when there are greater numbers to choose from. Apparently zebra have better eyesight but wildebeest have better hearing so the two complement each other.
There could be another reason. Our very own Meredith Palmer just published a paper about interspecies reaction to each other’s alarm calls, you can read it here: https://www.sciencedirect.com/science/article/pii/S0003347217304207
She found that zebra, wildebeest and impala recognise each other’s alarm calls but that they did not always respond in the same manner. When zebra sounded the alarm all three herbivores reacted strongly but when impala gave the alarm zebra where likely to ignore it, or assess the relative danger themselves. It seems that this varied response is down to predator size. Impala are prey to a wide range of smaller predators that would not be able to handle a mammal the size of a zebra, so when impala give the call it doesn’t always signal danger for the zebra. However when a zebra, the largest of the three herbivores sounds the alarm, whatever it has seen will probably be able to take down the wildebeest or the impala too so it’s prudent that all three scarper.
It is an interesting reaction and maybe wildebeest hang out with zebra because they are more trustworthy alarmists. I am not sure that the companionship of zebra and wildebeest can be classed as symbiotic I think it is more of an interaction due to a shared habitat but it seems that on some level they can benefit each other.
Whilst we wait for the next batch of Snapshot Serengeti images to be processed and posted up for us to classify I thought I would regale you with a short tail from my recent field work in Namibia. I was based on a cattle farm near to the small town of Otjiwarongo. One of the highlights, apart from the wealth of wildlife living alongside the cattle came as a total surprise. Mushrooms, giant, dinner plate sized tasty mushrooms.
Who would have thought to discover such a delicacy in the thorny scrubby bush of north eastern Namibia, a place normally thought of as desert.
I was out driving the boundaries of the farm with the owners one Saturday morning when they came to an abrupt stop and started reversing backwards. When we stopped they jumped out as if for action crying Omajowa! Thinking this was some Herero word for poacher or something similar I prepared myself for action too following them towards a very tall termite mound.
Omajowa were no poachers, they were giant mushrooms growing all around the base of the termite mound and according to my hosts, delicious. They expertly plucked a few out to take home for dinner and to share amongst the staff. We ate them cut into large chunks, breaded then fried like a schnitzel. Yes they were a taste to behold I can tell you.
The Ejova (singular, Herero name) or termitenpilz (German Namibian name) is the mushroom species Termitomyces schimperi. Termitomyces species are found over much of West, East and Southern Africa and live in association with various termite species.
In Namibia omajowa are found on the mounds of the termite Macrotermes michaelseni that build very tall mounds reaching heights of 5 meters tall. It has been noted that these often incline to the north.
The termites cultivate the fungus by providing a perfect substrate and perfect microclimate for the fungus to grow whist eliminating any competitors to the fungus. In return the fungus helps break down plant material aiding the efficient uptake of nutrients for the termites as well as providing additional food sources from its own body that are rich in nitrogen.
The omajowa, like most fungus is for the most part concealed away below ground but when conditions are right, in this case after a good rainfall between December and March the more familiar fruiting body emerges from the base of the termite mound growing on a stalk up to 50cm high with a cap that can reach 40cm diameter. Usually in groups of 5 to 10 up to 50 on one termite mound have been recorded in Namibia. They are really quite a sight.
From a cultural perspective they are seen by Namibians as a symbol of growth and prosperity and they are eagerly sought out. It is not unusual to see someone standing on the road side hefting one of these giants up in the air in an invitation to stop and buy from him.
Once pulled from the ground they have a strangely alien appearance with the dangling pseudorhiza (root like structure) still attached, though it is probably more ecologically sound to leave most of the pseudorhiza behind. The termites will feed on this and the remaining fungus will carry on growing to pop up another year. Like everything in nature, sustainable thoughtful use should be practiced in order preserve the delicate balance of life.
Camera-trapping has vastly opened up the possibilities of studying animals in the field in a relatively unobtrusive manner. Leaving a bunch of camera-traps clicking away 24/7 over a long period is generally cheaper than employing researchers to stay in the field providing them with accommodation, food and vehicles.
However it has its drawbacks. Good field skills are only learned over time spent in the field and although field researchers cannot operate 24/7 like the camera-traps they are less impartial observers noticing all kinds of fine details surrounding that which they study.
It is these observations that stimulate and inform new scientific questions and drives the understanding of the world around us. I am not suggesting that the results of camera-trap studies can’t also do this but since the days of the first naturalists it is being in the field that nurtures the very interest in studying wildlife in the first place.
The researcher who knows their study area well will be at an advantage to one who has planned from afar after using GIS. I know because I have been both. My first camera-trap project was on a reserve where I had lived for three years and that helped me know intuitively where I should place my camera-traps. On the other hand my latest project involved a very fine time window and I had to set up camera-traps on an unknown farm within two days of arriving. By the end of the 8 week period I was just starting to get a better feel for the place and could have kicked myself for not placing my cameras in the optimum places. When I went back to collect the cameras I found myself wading thigh high through a carpet of small yellow daisy-like flowers that left me coated waist down in a yellow stain. Had I have known the farm better realised this plant grew only in a few areas and could have avoided it entirely and saved myself the turmeric skin wash and a lot of miss-triggers.
My latest trip to Africa reminded me of why living in the field is so rewarding. Whilst the camera-traps are diligently collecting your data it gives you the chance to observe without frantically thinking of your research question, you can take time to take inspiration from the broader environment.
Near my tent was an old dead knob thorn tree that had five white-browed sparrow-weaver nests hanging like straw balls from it. Each night at dusk a pair of sparrow weavers would fly into the tree, call loudly as if claiming the spot and the female would dive into her preferred nest. The male would remain up high above waiting. Just as the last light was fading 3 or 4 small dark shapes would arrive and the sparrow weaver would chase after them squawking disapproval. Having seen them off he would come back and settle himself into the nest of his choice retiring for the night. Watching closely revealed, a few minutes later, the return of the invaders; two pairs of black-faced waxbills. They alighted at the top of the tree and cautiously made their way down towards the remaining nests finally one by one slipping quietly into the unused nests one couple per nest.
The thing about this little drama was that it was played out every night for over two months. None of the birds seemed to alter their routine and none where actively breeding at the time, they just had their bed time ritual. This was the kind of observation that the camera-traps will never quite capture as well as a human. In just the same way, although Snapshot Serengeti would not exist without the cameras it would be nothing without the human, citizen scientists behind the scenes sorting out the images. Even with computer recognition programs on the horizon I believe it would be foolish not to still use humans who’s innate sense of life will always pick up on something that is slightly odd, unusual or different about an image.
You are probably aware that the 225 camera traps of Snapshot Serengeti are set out in a grid pattern, spaced every 1km over a part of the Serengeti National Park. It sounds relatively simple but actually there is a lot of painstaking scientific pondering as to how exactly to set out your camera traps.
Over the last couple of decades there has been much debate as to the best way to design a camera trap study. The main choice, in terms of placement pattern, is whether to place your camera traps randomly or selectively and what kind of spacing/density to use.
Truly random is to grid your study site and then let a computer randomly choose which grid squares to place the cameras. Alternately you can choose a line or grid and place your camera trap at regular intervals regardless of where that may fall, still a random point. With selective placement each site is carefully chosen for a specific feature.
In reality most projects use a mixture of the above methods and the best method is really determined by what your scientific question is. For instance, if you where trying to acess the number of leopards in a given area it is better to place your camera traps strategically in places you know or guess leopards are most likely to pass rather than using a randomised method. However if you are carrying out a census of an area and wish to know what species are present then a randomised grid is ideal.
As I said a mix of methods is often used. Imagine setting out a grid in the comfort of your office on your computer. It looks good, covers a large area and promises good results. Once out in the field you navigate to your carefully worked out GPS reference point only to discover it is slap bang in the middle of a marsh or in a thick overgrown patch of thorn trees. This is where the scientists allow themselves a little leeway. Often they will take the GPS point as home base but choose an ideal spot within a certain radius of this point where perhaps there is a game trail or some other sign of animals passing, thus allowing them to select a good site within the vicinity.
I have recently had experience of this type of placement and I can say the work done in selecting your study site and then laying out your grid onto a map is laborious but not nearly as much as stomping through the bush keeping your fingers crossed that your next randomly selected site will be perfect. Turning up to emplacement three to find a thick tangle of vegetation is a little soul destroying, mostly you wonder if any animal is likely to bother to pass that way. The reality is that you normally find a spot that is better within 10 meters and with some slight pruning of the vegetation the sites can often turn out remarkably productive.
So that is the placement sorted but there is a long list of other agonising variables to consider, what settings to use on the camera trap itself, how many to use and how long to keep them up. Believe me every scientist designing studies deliberates the pros and cons of these factors and worries incessantly about if they have made the right choice. You don’t want to set up all you camera traps and leave them for a few months only to find your set up was not great, something which happened to me recently when I chose to set the camera trap on high sensitivity to make sure I had every chance of capturing the small, fast critters. The problem was it was so hot, 40°c plus, that the ambient waves of heat set the camera trap off almost permanently between 12pm and 5pm leaving me with 2000 images of nothing. I have had to compromise and reduce the sensitivity to avoid all the miss triggers; hopefully it won’t miss too many small things.
Snapshots camera traps have now been up for over 7 years so most of these teething problems have been ironed out. But as with the best laid plan you cannot control everything, the odd camera still malfunctions as I am sure that our regular classifiers can attest to!
When living in the bush in Africa your life becomes attuned to the rhythms of nature. Up with the sunrise, the spurfowl, guinea fowl and francolins won’t have it any other way, their raucous calls start well before the sun is actually visible. Physical work can be done until about mid day and then if possible its best to seek shelter till around 4pm when the sun is at least not high enough to cook you yet still pretty hot. By 8pm its dark so there is nothing else to do but sit back around a fire and let the night envelope you.
I am living so basically at the moment, my clothes are starting to look shabby after two weeks of hand washing in minimal water. I am however improving my skills daily at cooking on an open fire. It is amazing what you can do with a skillet, a pot and bits of old rebar and wire. I may have invented a new dish last night, Christmas Eve, when I conjured up a gemsbok stir fry.
The wood here gives new meaning to the term hard wood. Luckily for me there is a ready supply of wood due to the need for bush clearing on this cattle farm. Just a few pieces are enough to get really good coals glowing to cook over. They use a deep three legged cast iron pot in Africa for cooking stews, known as a potjie here in Southern Africa. I might even try my hand at bread next.
So last night after a good feed, Trev and I sat contemplating the embers whilst watching nightjars and bats hawking what looked like flying termites. It has rained recently triggering the eruption, earlier we watched guinea-fowl, hornbills, starlings, drongos and a whole host of other small birds running back and forth slurping them up straight from the holes before they could even get airborne. There is a constant suzzz of insect noise interrupted by the screech of barn owls and the odd jackal.
Then there is a deathly screech to rival that of the barn owl, what is it you ask? well it’s me. Something has just ran up my leg across my back up on to my head and then dropped down again to the ground between my feet. I am not usually given to screaming like a girl and creepy crawlies don’t usually bother me, but there is nothing quite like the dark to bring out the pathetic in us. So a quick scrabble for flash lights ensues and the culprit is spotted.
It’s a solifuge, otherwise known as a sun spider. Not actually a spider, though belonging to the same class, arachnida, they form an order by themselves, solifugae. They differ from spiders in not having silk glands and therefore do not spin webs. They appear to possess 10 legs but in fact the front most pair are actually pedipalps that act as sensors and aid in feeding. They are voracious predators and will eat anything they can overpower such as spiders, scorpions, insects and invertebrates.
Totally harmless to humans they do however install a lot of fear. This is partly due to two behavioural traits. If disturbed in the day the solifuge will head for the nearest dark place, often the very shadow cast by the human that caused the disturbance in the first place, giving the false impression that the solifuge is running at you in attack mode. Similarly at night they will follow a light source, again, often that of a human with a flash light.
The second trait is that they move like greased lightning. They are constantly zipping from here to there in a frantic search for prey to keep their high metabolism ticking over. They have also been known to take human hair to make their nests.
You are not likely to pick one of these up on Snapshot Serengeti’s camera-traps but if you ever get the chance to observe one of these arachnids going about its daily business it is really very fascinating, if of course you can get over your human fear.
You know you are in Africa when you wake up at the airport lodge on the edge of a capital city and stepping out from your room you come face to face with a bird that towers above you. Ostrich aside the dry heat of the Kalahari leaves you in no doubt you are in Africa.
I am in Namibia where I will be for the next two months. I am working on a cattle farm in the Waterberg plateau that is part of a greater nature conservancy. I have already got my camera-traps out, hopefully snapping away as I write. The idea is to look at how camera-trap spacing affects the chances of recording smaller mammals. There are plenty of those here, bat-eared fox, jackal, caracal, mongoose, pangolin, hare and aardwolf to name but a few.
The great thing about using camera-traps is that now they are up I have some weeks to wait before moving them so I have plenty of time to immerse myself in the African bush. I have already clocked up over 100 bird species in less than a week, its taking a while to get my ear back in gear, I keep hearing tantalisingly familiar calls but can’t quite remember who they belong to. It is the start of the rainy season and subsequently the breeding season so there is an awful lot of activity. The binoculars are back living on my shoulder and in use every few minutes.
The bush here consists of a lot of small bushes and trees interspersed with small open grass patches. Plenty of sickle bush, raisin bush and buffalo thorn. I forgot how hard it is to walk through, constantly getting hooked up on vicious thorns that grab at you as you pass.
The best bit of the trip is living in a tent, ok afternoon naps are impossible in the heat but you get to wake up early to the birds calling. The francolins and spurfowl are calling before the sun even rises. There are white browed sparrow weavers building nests in a tree near the tent that have the loveliest melodies. Then there is the night shift. It is pretty hard to fall asleep sometimes when the noises just make you want to get up and investigate. So far I have come face to face with a honey badger sniffing around our fire and several genets. The jackal’s shrill call is omnipresent but the one I listen out for is the rasping call of the leopard. I haven’t been disappointed, every other night that sound rumbles through me.
My internet connection is not so great but I should still be making regular posts for Snapshot Serengeti and there are still plenty of images to classify. We would like to run season 11 in the New Year if we can get season 10 completed. I may even have the odd camera-trap image from my Namibia project to share. Watch this space.
One of the groups of animals that seem to prove quite tricky to tell apart on Snapshot Serengeti are the small carnivores that belong to the canid and hyenid family. That is to say the jackals, black-backed and side-striped, the bat-eared fox and the aardwolf.
There are good reasons for this. Firstly they are predominantly nocturnal, though the jackals can often be seen in day light hours. Secondly they are small and constantly on the watch for larger predators. Studies have even shown that similar species such as coyotes are rather camera-trap shy so it could be possible these African cousins are avoiding the cameras. I noticed when looking for bat-eared fox images particularly that there are very few close up images, the foxes always seem to be in the distance. Something to maybe study?
So back to classifying, what’s the best way to tell these species apart?
Let’s start with the jackals, the most dog–like of the Serengeti’s small carnivores.
The first thing to note is there are actually three possible jackals to be found in the Serengeti but I will stick here to the side-striped and black-backed as the most common, the golden jackal doesn’t come up so often on our cameras but looks broadly the same as the other two with slightly more uniform colouring.
Jackals have dog like proportions with the shoulders and hind end approximately the same height. They have very pointed muzzles and large pointed ears. The black-backed can be distinguished by its black saddle running from the back of the neck through the shoulders up to a point at the top of the tail. It is flecked with white hairs giving a grizzled appearance. The rest of the body is a sandy colour. The side-striped is more uniform grey brown with a flash down its side both light and dark but lacking the saddle. The tip of the tail is often white. Their ears are smaller than black-backed jackal.
The bat-eared fox meanwhile is a strange looking creature. All three of these carnivores have large ears to help them locate prey but the bat-eared fox wins the prize. Its ears dwarf its little face which is very small. They need these huge ears to locate their insect prey. Over all bat-eared foxes are the smallest of the three and have a rather plain silver/grey coat with dark legs, ears and upper parts of its thick bushy tail. If you are not sure look at the over all posture. The jackals hold their head high on a strong neck but the little bat-eared fox often has his head down and appears to have no neck.
Aardwolf, although not canids, are included here because in size and shape they are very similar to the other two. Fortunately these guys have distinctive striped coats which help separate them from all but the much larger and very rare (in Snapshot Serengeti) striped hyena. The aardwolf seems to have a rather thick long neck and a much more hyena shaped heavy muzzle.
So the tip here is to look closely at body form as well as colour, hopefully seeing these images of the three together will be helpful next time you get stuck classifying.
Snapshot Serengeti has around 225 camera-traps laid out in a grid in the heart of the Serengeti National Park. They have been there for around 7 years and make up one of the longest running camera-trap monitoring projects in the world. Snapshot was launched on the Zooniverse portal in December 2012 and has inspired many more similar camera-trap projects from around the world. So Happy 5th Birthday to us, may there be many more to come.
There is no doubt that camera-trapping has gripped the hearts and imagination of both scientists and the public. Eight years ago when I first used camera-traps I had to explain them very carefully to friends and family as they had never encountered them, these days references to camera-traps appear in popular press articles and wildlife documentaries and most people have a basic idea of their use in conservation.
It was K. Ullas Karanth, an Indian wildlife zoologist, who is credited with pioneering the use of camera-traps as scientific tools in his study of tigers in the 1990’s. In the last two decades the technique has advanced at a hugely fast pace and has revolutionised the study of elusive and seemingly well known species alike. It is a scientists dream to observe animals without being present yourself to influence their behaviour.
But looking at the history of the discipline I can across many references to much earlier work using camera-traps. Back in 1927 National Geographic published an article by Frank M Chapman titled delightfully “Who Treads Our Trails”. The piece opens with this amazing paragraph
“If there be any sport in which the joys of anticipation are more prolonged, the pleasures of realisation more enduring, than that of camera trapping in the Tropics I have yet to find it!”
This guy would have loved Snapshot Serengeti. This is most likely the very first scientific paper to report on using camera-traps all be it very different cameras. His rig involved a tripwire the animal steps on rigged up to the camera shutter and bowls of magnesium that will explode and create the flash needed to illuminate the animal at night time. It seems incredible now that this would be allowed considering today’s ethically minded ethos but the author himself points out that the alternatives to studying animals could include using dogs or trappers to catch an animal or even poison bait. He decides he wants a census of the living not a record of the dead and so the idea of camera-traps for scientific study are born. He drew heavily from the work of George Shiras who published the first pictures taken by remote camera back in 1906 (also in National Geographic). George Shiras took the pictures for the pictures sake only later becoming involved with conservation but Frank Chapman was a true scientist.
Obviously the technology has changed a lot and the loud noisy explosions that accompanied Franks work have been replaced by covert black IR where even the glow of the infra-red flash is almost invisible. He would marvel at the amount of pictures that can be stored on an average SD card and that camera-traps are being used from the tropics to the snowfields of Antarctica.
You can look for the original article with this reference:
Chapman, F.M., September 1927. “Who Treads Our Trails?“, National Geographic, 52(3), 331-345
Or visit this site to see some of Frank Chapman’s images: http://www.naturespy.org/2014/03/camera-traps-science/
This summer in South West France has not been its usual hot balmy self. In fact as I look out the window now the overriding colour is a deep lush green. Normally by July it is turning a straw yellow colour but this year we have had plenty of rain. In contrast, to the south of us, fires have been raging through Portugal, Spain and South Eastern France. Who knows if this is a taste of what’s to come or a one year glitch in the system but one thing is for sure climate change is going to affect life on this planet in both subtle and not so subtle ways.
I wrote about termites last week and their importance in the ecosystem. This week I read a disturbing news article about aardvark, who of course survives on eating termites and ants.
A group of scientists in South Africa were studying aardvarks in the Kalahari. They had inserted biologgers into several aardvarks in order to follow their activity and body temperature. It turned out that the year of their study was an exceptional year of draught and all but one of the study animals along with others in the area died. They unexpectedly recorded a phenomenon not seen before that should be an eye opener to the ways in which future climate could affect not only individual species but whole ecosystems.
The aardvark themselves can withstand high temperatures but the termites on which they rely for food and water cannot. With the information provided by the biologgers the scientific team where able to see that the aardvark were not finding enough termites or ants to keep their energy levels up. Night times can be pretty cold in the Kalahari and the team found that the starving aardvark even swapped their usual night time foraging behaviour to day time in order to conserve body energy. They were even seen sunbathing in a bid to save energy. It seems that none of this adaptive behaviour was enough. There simply was not enough food for their needs and they slowly starved to death. At an average weight of 60 to 80 kg an aardvark is a large animal and needs to eat around 50 000 termites or ants a night.
One or two bad years will always happen but if climate change shifts as it is predicted many areas of Africa will become drier and hotter creating an aridity that most of the native termites and ants cannot tolerate. True, given time, more tolerant species may take over but in the meantime the much loved aardvark may become a creature of the past. But that is not the end of the story. The aardvark is more than just a curiously put together animal, it is the architect of large burrow systems that many other mammals, birds and reptiles are reliant on to escape extremes of hot and cold weather, to bring up their young and escape from predators. Most cannot excavate the hard earth themselves so with the possible demise of aardvark life would get a whole lot tougher for many many more animals.
If you want to read more about the study have a look at this link https://africageographic.com/blog/aardvarks-beating-climate-change/