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The Other Great Migration

White Stork

 

I am sitting at home in France in a sweltering 40oc listening to golden orioles calling from the tall riverine trees. I could definitely be in Africa, though if I was I would probably be somewhat reluctant to jump in the river to cool off, something I am about to do, what with all the hippo and crocs that the Serengeti is so famous for.

It has got me thinking though about all our shared birds between Africa and Europe. Hearing the orioles today has made me realise that they will be setting off very soon, in the next couple of weeks probably, for their return trip to their wintering grounds in Africa.

Now the Serengeti is justly known for its rather famous herbivore migration but to me it is utterly fascinating that birds, particularly the tiny ones are also taking part in seasonal movements that cover 1000’s of kilometres.

It’s a dangerous journey, they risk predation, starvation and severe weather and if that’s not enough they have to pass over several places where humans think blasting as many of them out of the sky as possible is sport. For the birds migrating from Europe to Africa they have to fly over open sea and a lot have to negotiate the Sahara Desert, an area around the size of the United States. It is estimated that 500 million birds have to cross this unforgiving wilderness and some do it in a long nonstop flight. Just imagine how exhausted they are the when they reach the safety of the green belts that fringe it. My husband used to work in the Sahara and can attest to finding dozens of swallows just lying panting on the ground, being able to pick them up and give them water before launching them onwards.

So why do they do it, well much the same reason as wildebeest and zebra do, resources. Birds have the very special ability to travel very efficiently, it has been said that a small bird can fly the same distance in hours that an elephant would cover in three days. With this ability birds are able to switch geographical areas in order to take advantage of seasonal food supplies and so they enjoy the best of both worlds in terms of food abundance despite the risk involved with moving the great distance between the two. Risk versus reward.

Unlike the Serengeti herbivore migration birds have many different strategies when it comes to undertaking their colossal movements often depending on the species unique design. Many small passerines will migrate in small groups, travelling at night and will try for the shortest, most direct route. A kind of fast and furious approach that relies on having fed up well and being able to feed quickly at the few places they do stop to refuel. Other birds, particularly waders will take a more leisurely approach flying down waterways and coasts, stopping for days or weeks at a time to feed up before moving on. Many raptors and storks cross the Mediterranean Sea over Gibraltar and Tarifa in Spain. It is roughly a 14 kilometre crossing. It is an amazing spectacle to see. Thousands of birds can be seen soaring around in the late morning over land waiting for the thermals to build up which they will use to ride across the sea to Africa. It’s kind of like surfing only on hot air.

Once they get to Africa of course they have a huge choice of where to go and they spread out accordingly, many making it all the way to South Africa. In fact we still don’t know where a lot of them go, something that is vital to understanding the threats facing them today.

So who are the feathered migrants that we may see in the Serengeti? Well across Tanzania there are thought to be around 160 species of Palaearctic/African migrants. The Palaearctic is a large region covering Europe, Russia, North Africa, Arabia and parts of Asia so that’s a lot of movement.

Some of Europe’s smallest birds can be found in the Serengeti amongst them willow warblers, wood warblers and blackcaps. Spotted flycatchers and several shrikes can be easily seen. The common cuckoo is trickier as it is, like many migrants, silent outside of its breeding ground. European bee-eaters and rollers meet up with their African cousins as do barn swallows and common house martins.

Even raptors make it to the famous park; lesser spotted, steppe and imperial eagles all breed in the Palaearctic. Eurasian marsh harrier, black kite and common buzzard all enjoy the warm African conditions before heading back north to breed.

For Snapshot Serengeti followers the most commonly seen migrants on our camera-traps are probably storks, white storks and black storks all take the long journey north for breeding. More surprisingly given it is not noted for its water even European ducks have been spotted in the Serengeti, wigeon, Eurasian teal and garganey amongst them.

This is not an exhaustive list but gives you an idea of the level in which the two continents are connected through their shared avian fauna and reminds us of what a truly global planet we live on.

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Snapshot of a Crossroads

When we think of Snapshot Serengeti we think about the massive array of 225 camera-traps that are spread over 1125 km2 in the Serengeti National Park permanently clicking away. Partly this is fostered by the fact that when citizen scientists help out classifying images for the project they are randomly assigned images from a mixture of the 225 camera-traps rather than a sequential set from one camera. This is done so that each member of the community gets the chance to see a good range of different animals rather than, say, getting a camera-trap that was triggered 1000’s of times by grass.

For the most part anyway, people are concentrating so hard on the animals in the image that the scenery in the back ground is almost incidental. Regular contributors though will be aware that there are one or two camera-traps that are in very recognisable locations for example one trained on a group of boulders and one on a log. For some reason these spots seem to produce some really memorable images; the log was the scene of our melanistic serval as well as lion cubs, the boulder gave us some stunning images of spotted eagle-owl.

Recently the most epic capture event ever on Snapshot Serengeti surfaced of a pride of lions hunting a buffalo (if you missed it look here, https://www.facebook.com/SnapshotSerengeti/). That sequence was captured at a special little spot in the Serengeti, Dik-Dik Corner. The view is basically of a lone tree standing at a three-way cross road in animal tracks. There seems to be a pair of dik dik who hold this area central to their territory and they appear regularly, hence the name, but they are certainly not the only ones.

Here is a slide show of the passing wildlife at Dik Dik corner.

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Of course these are not the only critters to have passed this way but this selection really shows how the animals follow the trails, something camera-trap researchers have used to their advantage over the years.

Summertime

Butterflies on buddleia

 

Its summer time again and that means the research teams are out in the field collecting data. The Snapshot Safari team have been checking up on all the camera trap projects dotted across Africa and adding more to the list at the same time as clocking up adventure stories from their travels. Snapshot Serengeti’s Dr Michael Anderson and his team are continuing with their resource partitioning research in the Serengeti and using the opportunity to check up on the condition of our camera traps, probably, as they do each year, replacing one or two that have malfunctioned or been damaged beyond repair.

So whilst they are doing their part for science I am stuck here in France behind my computer catching up with report writing. Though being summer and me an ecologist it is so very easy to get distracted by the outside world.

This year has been a bonanza year for invertebrate locally. The spring started with a mass eruption of the invasive box moth (Cydalima perspectalis). Literally every blooming flower was coated, snow like with their white bodies; one lime tree in our garden we estimated at over 100 000 moths. The caterpillars have decimated the local box (Boxus spp) forests but I was beginning to wonder what effect the millions of moths would have on food resources for other insects. I needn’t have worried, the box moths have gone and summer blooms have brought out hundreds of other butterflies and beetles, bees and spiders. It is an entomologist’s heaven out there.

This seems to have had a knock on effect in the birds. Never have I discovered so many active birds’ nests near to my house. Several rounds of blackbirds, chaffinches and black red-starts have fledged already and the hedges have been awash with the calls of nightingales, black caps and wrens. The air positively rings with the sound of begging baby birds.

Just two meters from my balcony there is a chaffinch nest in the hibiscus with four babies ready to fledge. It is so close that I barely need binoculars to watch the goings on. This is always a great delight for an ecologist or naturalist because it gives you just that little bit more insight to the nesting habits of common birds.

At first appearance it seems just the female was caring for the young birds but then I realised that every time she arrived, flying in at the base of an adjacent bush and making her way to the nest in stealth mode there was another chaffinch calling loudly from a high point in a not too distant tree. It didn’t take too long to realise that this was the male acting as decoy to draw the attention of any would be predators away from the real action. Once the female finished stuffing hungry beaks with juicy insects and flew off, the male was right behind her only to reappear in his tree top squawking seconds before she arrived back with another beak-full.

Thanks to this pairs faith in nesting close to my house I have had lots of time to watch the great team effort of these little common birds.

So whilst feeling somewhat jealous of my team colleagues who are out enjoying themselves in the African sun it is worth remembering just how much goes on under our very own noses and just how wonderful nature is.

Zorilla

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Zorilla – a rare find!

 

A few years back the Snapshot Serengeti community classified its first ever zorilla (Ictonyx striatus). It’s not an animal that most people are familiar with and you would probably not expect to even see one on a safari in Africa. It is certainly not on the big five list or even on the little five list but just like its bigger cousin the honey badger it’s a gutsy little creature.

The zorilla, or African striped polecat belongs to the Mustelidae family that includes the well known honey badger, otters and weasels. Although superficially similar looking to skunks they are unrelated.

So how would you recognise one? First of all they are small, only 28 – 38 cm long with a bushy tail of around 25cm. The most striking feature is the black and white stripy coat. The body is overall black with four white stripes running from the head to the tail which is mostly white. There are white patches on the face and head and the small ears are often white rimmed. The fur is quite long lending the zorilla a slightly scruffy appearance.

Zorillas share more than their looks with skunks; they are also able to squirt noxious smelling liquid from their anal glands as a defence mechanism against predators. So if you do ever encounter one, give this little guy the respect it demands and stay well back.

These tough little creatures will eat a wide range of items, invertebrates, reptiles, rodents and birds but they seem to favour rodents and insects. They are known to tackle venomous snakes and large rats by pinning them to the ground and repeatedly biting at the back of the neck to make the kill. Nocturnal, they find most prey by smell and won’t hesitate to follow prey down into burrows or use their strong claws to un-earth something. Its small elongated size is perfectly adapted for this task.

Zorillas are found across sub Saharan Africa in a wide variety of habitats but seem to avoid the wetter rainforest belt through west and central Africa. They are mainly terrestrial but are known to be good climbers and happy to swim if needed. Due to their widespread presence in Africa their conservation status is classed as Least Concern by the IUCN red list.

So why don’t we see more on our camera-traps? Well not much is known about zorillas, their small size and nocturnal habits make them hard to study and in a place like the Serengeti they are just not a high priority species. However we do know they are present because they do show up on the camera-traps from time to time. I suspect that the main reason they are not picked up more frequently is their small size coupled with their fast paced frenetic life. The weasel family is notoriously hard to capture on camera-trap as they tend to shoot through the trigger zone before the camera has got its-self together to trigger. Perhaps we will see more zorillas in the future when the camera trigger speeds increase.

 

Lions

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This is a great sequence from one of our 225 camera-traps that are tirelessly snapping away in the heart of the Serengeti National Park. One of the largest and longest running camera-trap projects, Snapshot Serengeti has been running for over 8 years with out a break.

The millions of images generated by so many cameras are processed by the amazing online community of citizen scientists without whom the team of scientists would probably still be working their way through season 2 rather than ploughing their way through season 10 (that’s were we are at currently, November 2015 to September 2016).

Those of you who have helped out on Snapshot Serengeti will realise that there is a great variety of images that come up, they are randomly assigned to each classifier and currently have to have at least 10 matched classifications before being retired. A great many are of grass or the tail end of animals as they pass by. Its the frustration of camera-trapping, when you look at the results you just wish you could nudge the camera to the left a bit to get a better image but of course its way to late for that once you have the image safely in hand.

But every once in a while we get a stunning image worthy of a professional photographer or one that shows really interesting behaviour and those are the images that get people hooked on returning day after day to help out on Snapshot Serengeti. A little fix of wildlife in its environment enjoyed from your home.

This sequence of a lion pride is great. In all likely hood the four individuals we can see here are not the only members, others could be out of frame. It looks as though the female has a pink tone to her muzzle, now it could be a trick of the light but its also possible that the pride have recently fed. The full looking belly and the relaxed nature of the other members would lend weight to this possibility but we will never know for sure (unless more images from that camera-trap reveal more proof!)

It is most definitely one of those moments when you wish you could pan the camera around to see what else is going on, did we almost get a kill on camera? are there a bunch of cubs laying under a bush to the right? are there a pair of resplendent pride males slumbering to the left?

If you do discover more from this series do let us know but for the time being we shall have to let our imagination ramble.

The African Buffalo, Success in a Crowd

African Buffalo Herd

 

 

Lately we seem to have had some great buffalo images. These big imposing beasts aren’t exactly pretty but they have an appeal of their own with their imposing bulk.

There are 4 recognised subspecies of the African buffalo (Syncerus caffer), three savannah buffalo and one forest buffalo. Here in the Serengeti we find Cape buffalo (S c caffer) the biggest of the three savannah species also known as southern savanna buffalo. It weighs in at a whopping 500- 900 kg for males or 350-620kg for females. The two other savannah species are West African savanna buffalo (S. c. brachyceros) and Central African savanna buffalo (S. c. aequinoctialis) both slightly smaller than their Cape buffalo cousins.

The forest buffalo (S. c. nanus) appears quite different being redder in colour and quite a bit smaller weighing around 265-320kg but it is thought that this is in fact the ancestral African buffalo from which the others evolved. According to the IUCN Red-List although the three savannah species appear similar they are at least as different from one another as they are from the more distinct forest buffalo. Defining subspecies is always tricky and apparently there is hybridisation where these different subspecies meet, including between savannah and forest subspecies. I witnessed this when working in the Central African Republic where you could see smaller red ‘forest’ type buffalo intermingled with bigger looking dark ‘savannah’ type.

So what makes African buffalo so special? You would imagine that such a large animal would not seek safety in numbers but this animal is highly gregarious. Herds can reach thousands strong but these tend to be temporary and the usual number is dozens to hundreds formed of clans of related females and their offspring and an assortment of males. The rest of the males form small bachelor herds of 5-10 animals or live alone.

Living in these large herds gives buffalo a certain security and they are highly protective. They are known to chase predators as a herd in order to ‘rescue’ a targeted individual. They don’t hesitate to run at lions if they are threatened. This is to be expected when there are young calves about but buffalo herds are known to extend this behaviour towards injured, sick and even blind herd members. It is so effective that it is actually males not living in large groups, particularly the loners that are most often preyed upon by their arch enemy, the lion. When buffalos are on the move dominant females lead the way with mothers and calves in the centre followed by any infirm individuals and older cows with males forming a protective ring around the entire herd.

Formidable indeed but of course the very thing that allows them to be so aggressive, their size, is also the thing that attracts lion the only true threat other than man to an adult African buffalo.

As a species the African buffalo is listed as ‘least concern’ on the IUNC Red-List due to its widespread distribution. That doesn’t mean that there are not conservation issues. Buffalo are often targeted by poachers for the obvious reason that they provide a rich reward in meat, the usual land reduction is a factor and in areas outside game reserves they are often killed as they compete with domestic cattle for food.

Historically buffalo numbers plummeted in the 1890’s due to the rinderpest epidemic that saw the disease spread from domestic cattle to wild ungulates. The disease continues to have small outbreaks. More recently bovine tuberculoses, again spread from domestic cattle to buffalos, in the Kruger National Park has also caused mortality as well as triggering a cascade of health issues in other animals, in particular, lions who eat infected buffalo. A whole industry has grown up with the sole purpose of breeding TB free African buffalo in South Africa. On the whole though African buffalo are well represented with strong populations in protected areas and as long as these remain their status looks to be stable.

The male and female have large horns that are fused at the base forming a boss across their heads, in the male though this becomes thickened and sometimes massive and fighting males will crash bosses together if things become serious and posturing doesn’t work. The impact is so intense that they risk killing themselves or their rivals.

 

Big male Cape buffalo

 

 

Next time you find a buffalo image, see if you can work out if it is male or female and take sometime to reflect on these formidable beasts.

New and Improved Image Batch

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Last week the amazing community of classifiers on Snapshot Serengeti managed to complete the current batch of images. That doesn’t mean that this season is done with. It used to be that the whole season would be uploaded all at once on to the Zooniverse platform but these days with ever increasing image sizes and plenty more projects taking part space has become a bit of an issue. So now we upload in batches.

Normally we would have the new one ready to go straight away but as long time followers of Snapshot Serengeti may have noticed we have been having some image quality problems since swapping over to a new Panoptes platform.

We have finally found someone who is able to sort out this problem for us and he is working on it as we speak but the Snapshot Safari team decided that delaying the new batch of images for a short while to bring you better quality images to classify was worth the wait.

So we will be back shortly, new and improved and hope that it will improve your experience on the site.

In the meantime here is a sequence of cute elephant interaction captured in the last batch. Enjoy.

 

 

The Race

 

 

Recently the science team behind Snapshot Serengeti, lead by Dr Michael Anderson, were wandering around the plains going about their latest research (more about that soon) when they got to witness a sight of high intensity, namely a bit of large predator interaction.

The drama occurred around an area known as the Maasi Kopjes. The team at this stage were in their vehicle, as a lioness was nearby, when they noticed a lone cheetah wandering into the lioness’s territory.

 

The cheetah is obviously anxious as can be seen in this image.

Nervously attentive cheetah

 

The lioness quickly picks up the intruders scent and as Michael tells me used their vehicle as cover to stalk closer to the cheetah.

Lioness watching cheetah

 

Initially the cheetah was unaware of its impending doom but the lioness’s indignation at the intrusion possibly affected her stealth and the cheetah finally noticed her approach.

The race was on. The big cat race.

From these shots you can see the sudden acceleration of the cheetah and yes, it got away, living to see another day and the lioness happily securing her domain on her territory.

Perhaps you will be lucky enough to see both these animals on our camera-traps!

Thanks to Dr Michael Anderson for sharing his Photo’s with us.

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.

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.