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A Touch Of Colour

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!

 

Leucistic Waterbuck

 

 

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.

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Best of Friends

wildebeest and zebra

 

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.

The Giraffe and the Oxpecker

IMAG0415

 

Those of you who follow our Facebook page will have seen recently that Meredith Palmer, one of Snapshot Serengeti’s scientists and PhD candidate with Minnesota University just published a paper in African Journal of Ecology with the catchy title;

Giraffe Bed and Breakfast: Camera traps reveal Tanzanian yellow-billed oxpeckers roosting on their large mammalian hosts.

The paper highlights one of the more unusual behaviour traits documented by our cameras and discovered by our classifiers of yellow-billed oxpeckers (Buphagus africanus) roosting on giraffe at night time.

Those of you that have been with us a while may have had the pleasure of finding one of these night time images of giraffe with oxpeckers tucked up safe and snug between their back legs. In fact I wrote a blog about this back in 2014.

https://blog.snapshotserengeti.org/2014/01/17/the-curious-case-of-the-giraffe-and-the-oxpecker/

Two species of oxpecker are found in the Serengeti, the red-billed and the yellow-billed oxpeckers. Whilst the red-billed will feed from a wide range of hosts from impala and wart hog to hippos the yellow-billed oxpecker is more discerning and prefers large hosts such as buffalo, eland and giraffe. The problem with this choice is that these animals are far roaming and if the birds were to find trees to roost in at night, and these can be sparse in the Serengeti, the yellow-billed oxpecker could struggle to locate its host the following morning. It seems they have overcome the problem by staying over on the hosts. What’s more is these clever birds have opted for the premium rate rooms where they are not disturbed during the night for, as is well documented, giraffe almost never lay or sit down at night time preferring to stay upright.

So although during the day yellow-billed oxpeckers are found on several large mammal hosts most of the night time images are of giraffe roosts. It seems they also have a preference for the groin area of the giraffe. It is not hard to imagine that this would be the warmest safest spot on the giraffe, the cavity created where the two hind legs meet is spacious enough to accommodate a small flock of birds and of course is also very attractive to ticks so if they fancied a mid-night snack…..

It is these unexpected discoveries that make the project so exciting and worth all our effort in taking part so next time you are racing through the classifications take a little time to have a closer look at the images, you never know what is waiting to be discovered.

 

If you want to read more about Meredith’s paper you can read the following:

https://news.nationalgeographic.com/2018/02/animals-serengeti-tanzania-birds/

 

 

 

 

Observations on Observations

White-browed sparrow weaver nests

 

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.

The Sun Spider

315px-Solifugae_Solpugidae_-_Jerrymunglum_female_Dorsal_aspect

Solifuge credit: Jon Richfield Wikimedia CC BY-SA 3.0

 

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.

Back in Africa

The Waterberg Plateau

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.

Identifying Small Carnivores

 

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.

 

 

 

 

 

 

 

 

 

Happy Birthday To Us

Camera-trap

 

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/

Unusual Critters

There is a small mammal that is found in the Serengeti which I am not sure we have ever captured on camera-trap or if we have most of you won’t have got the chance to classify them as the capture rate will be very low.

It is not because they are rare or even that elusive, visit the Serengeti or any number of suitable reserves across Africa and you will bump into these odd little creatures. It is just that they are very restricted by their habitat which is rocky outcrops.

The mammal I am talking about is a relative of the elephant, yes that’s right, the largest land mammal is cousin to this rabbit sized African curiosity, the hyrax otherwise known as rock rabbits or dassies. It seems that the two species split some 70 odd million years ago so plenty of time to both specialise in their own way. However one odd trait the hyrax retained was a long gestation period (7 months) more similar to larger mammals. Compare this to scrub hares that have a gestation period of around 42 days. New born hyraxes are extremely well developed and commence eating grass within a few days of birth. Unusually for a small mammal life expectancy is long, up to 12 years.

 

Rock Hyrax  Procavia Capensis

Rock Hyrax

 

Photo Credit: Max Pixel; creative commons zero- cco

 

There are two species of hyrax we could encounter in the Serengeti, the rock hyrax (Procavia sp) and the bush hyrax (Heterohyrax brucei). In fact they can even be seen side by side sunning themselves on rocks. Although they both make their homes in rocky outcrops the two have decidedly different life styles. The rock hyrax eats predominantly grasses and rarely strays far from rocky out crops, conversely the bush hyrax eats mainly leaves, twigs and bark which it climbs trees to eat. The two species however live in colonies in rocks and in the Serengeti at least these colonies can be a mix of both species. The rocky retreats act not only as safety from the many predators that eat hyrax but also offer a way to thermo-regulate.

It’s a wonder that these closely related species don’t hybridise but it seems they have extremely different genital structures as well as the differing dental work needed to cope with the different diets. All species have long sharp upper incisors that are often used in dominance scuffles, hyrax can be very bad tempered and those incisors can inflict serious damage.

 

Bush Hyrax showing incisors

 

Photo Credit: Peter Steward, Flickr CC-BY-NC2.0

 

Living in a relatively small area and in colonies has lead to some interesting behaviour amongst hyrax. They use latrines which are thought to be centuries old. In fact you can often spot the white stains on the rocks of an active colony.

All in all a fascinating little creature, if you are ever faced with a snapshot image with rocks in, take a good look to see if you can’t see a hyrax sitting there.

Kori bustard; Strutting its stuff in the Serengeti.

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I found this series of captures from one of the Snapshot Serengeti camera-traps. It shows nicely the way a kori bustard cruises around the savannah looking for things to eat. With males reaching up to 19kg these birds are Africa’s heaviest flying bird.  In order to get airborne these birds need a lot of space as they must run to gain momentum. Once airborne their big powerful wings mean they can fly at quite a speed. However they only fly when pushed spending most of their time walking sedately through grasslands.

Found in two main pockets, south, south west Africa and east Africa they favour flat arid open country. The Serengeti plains are ideal habitat. Here they amble around looking for a wide variety of food eating berries, seeds and other plant matter as well as lizards, snakes, rodents and birds. They are known to gather in quite some numbers where there are infestations of locust or other insects. Like other large ground birds recent fires also attract them where they search for scorched or injured small animals. Kori bustards are known to drink water using a sucking motion which is unusual for birds.

Not unexpectedly for such a large bird, they do not roost in trees preferring to bed down on the ground which is also where they build their nests. However they do like to choose a feature to build their scrape of a nest near, perhaps a rock  or tree stump or even a clump of grass. Not such a silly idea to choose a landmark in an otherwise featureless landscape.

A kori bustard chick is precocial meaning it can walk around almost as soon as it is born, very important for ground nesting birds. It shares a common trait with other ground nesters of having a cryptic plumage completely different to the adult plumage that helps conceal the young from predators. The stripy baby is also very cute.

 

Kori bustard chick

Credit: Photo by Mehgan Murphy, Smithsonian’s National Zoo (CC BY-NC-ND 2.0)

Although the kori bustard does very well in the Serengeti outside of protected areas they have suffered like so many other animals from a reduction in numbers through loss of habitat and falling prey to hunters.