Tuesday, 31 May 2011

Drinking birds

You're never far from a dove in East Africa, and if you sit by a waterhole waiting for something exciting to drop in, you might spend a little time point out how birds drink. Start by watching the clouds of quelea often around (don't forget to talk about them too, since they're fascinating birds we'll have a blog on later!).

Clouds of Red-billed Quelea drinking in Tarangire NP, May 2011

As they come in to drink you'll see them dipping their beak into the water, tipping their head back and letting the water flow back to their crops then repeating the process. Most birds drink like this - they can't suck as we can, so have to 'sip and tip' to do so. But there are some exceptions, one of which is pretty sure to turn up at every waterhole within a few moments of you: Doves (also sandgrouse, which we believe to be closely related to doves, and a few parrots).

Not drinking (sorry) but an Emerald-spotted Wood Dove in Kruger NP, May 2011
Watch a dove drinking and you'll see it open it's beak slight underwater, and then just keep it's head there as it uses capiliary action to pull the water into the beak, then it's tongue as a piston to pump water into its throat. It's a very different drinking action that will be immediately obvious. And it was obvious to many naturalists in Europe a long time ago - most birds lift their beaks to heaven to give thanks to God for the water between each sip, but those ungrateful doves must have something to do with the devil because they keep their heads down the whole time... Unfortunately I can't find any more details of this superstition online, because google dove, drinking and heaven and you find far too many links to the Biblical references to the dove (the closest is here). But it's still a good story!

And, of course, if you should happen to see a sandgrouse come in you'll see the same drinking, but you might also see the males (only males apparently) filling their specially adapted breast-feathers to take water back for the chicks. Their dry, seed-filled diet means all sandgrouse have to drink daily, and estimates suggest that in the driest times of the year adults may fly a round trip of up to 160km from the nest to waterholes in some species. Even though they are very fast fliers - they can easily do 70kph - that's still a long trip! (Sandgrouse facts from here, but you probably won't have free access.)

Monday, 30 May 2011

10 things to talk about when there are no lions!

I've been thinking about interesting stories to share with safari visitors on those days when the wildlife just won't play for quite some time. When you're watching a lion pull down a zebra, the jackals are nipping in and out and the vultures are gathering it's easy to be a good guide. The real test is when you're somewhere and the wet season has arrived early and all the animals migrated elsewhere. How do you entertain people then?! So I've started a list of topics that I think can be interesting to chat about in those quieter times, focussing on things that are pretty much always around you in the bush, so easy to chat about in a natural way. I've said 10 things, because lists are easy - but I've already got 11 topics (10% extra free), and expect there'll be more to come. The main thing is that each of these topics is something to chat about in a quieter time. I'll be expanding on the titles in future posts, but here's the initial list to get you thinking...

(1) Grass - there's a lot of it in the savannah and surely it's got to be interesting!
(2) Fire - one of the main processes shaing the savannah, there's usually signs of it around and it's not a process many people from outside Africa think of as important or normal.
(3) Geology - not only does East Africa have a host of interesting geological features, from the Rift Valley and various volcanos, to Kopjes and plains, but the geology shapes the ecosystem by altering large-scale nutrient availability
(4) Climate and weather - I'm British, I always talk about the weather. But the East African climate is also pretty special and unusual to most visitors here.
(5) Termites - you're never far from a termite mound, and even closer to many non-mound building termites and again, they play a massive role in the savannah ecosystem.
(6) Thorns and other plant defences - everything is prickly in Africa (much more so than in many other places)
(7) Birds - a personal favourite, there are great stories to tell about birds and even if the mammals have gone the birds will still be around!
(8) Invertebrates - butterflies and dragonflies are also great for stories if you learn a few of the species.
(9) People - despite the lack of people in East Africa's National Parks, people are part of the savannah ecosystem and always have been. There's lots of evidence of it around too...
(10) Conservation - visitors often want to talk about conservation issues (and who knows, you migh just bump into an animal with a snare wound), so it's good to know the details and be able to talk in an informed way.

Of course, there are other topics too (I've one more up my sleeve already), but this is a good start. Hopefully we'll start getting posts up for each of these topics - watch this space!

Sunday, 29 May 2011

Savannah Ecology

Most East African safaris spend a lot of time in the savannah biome. Forests and coastal areas are also popular, but the savannah is where the safari focussed and a basic understanding of the ecology of this biome will make a visit much more interesting. You can read more about savannahs and the savanna biome here on Wikipedia, of course, and there's a large team making sure that post is up to date. But I like to break into the subject rather differently so will do my own thing here, with future posts picking up the threads we identfy here.

Let's start by defining the savannah biome. Note first that I'm trying to be careful to talk of a biome here, not simply a habitat - the savannah biome is made up of many different habitats from grasslands and woodlands, to kopjes and swamps. Each of these habitats (and others) play an important role in the savannah biome and we'll visit them individually in future posts. In fact, the biome is defined as a grass dominated system - the grasslands are obviously part of the savannah ecosystem, but the woodlands and other habitats also have an understory dominated by grasses. The two photos above show typical grassland savannah from Kruger NP (South Africa) in the top (plus White Rhino) and an Acacia woodland (plue Oryx) with thick grassy understory in Tarangire NP (Tanzania). Other savannahs might looks less familiar to East African safari types - check the nice shot of a Guinea savanna in West Africa here, and the interesting savannah woodlands of Australia here. All savannahs, as all grass dominated ecosystems.

Right, definition out of the way it's time to introduce the Big Four of the savannah (sorry, moved on from the original three, but still can't make five!) - the four processes that shape the savannah biome globally. With an understanding of each of these, you can start to understand savannah ecology and begin to guess at what drives the patterns you see in this biome.

Firstly, there's climate and particularly water availability. Temperature and rainfall/precipitation combine to define the earth's major biomes - to get savannah, you need to be warm and fairly dry. Too wet and you'll end up with a forest of one type or another, to dry and you'll head rapidly towards desert. In fact, globally the savannah biome tends to dominate in tropical areas with rainfall above about 400mm, and below something between 1400 and 1650mm. Within this range, depending on how the other big processes combine, you'll probably get savannah habitats of one form or another - though how they look depends exactly where you are on the rainfall gradient. And, of course, understanding seasonal rainfall patterns are vital to understanding the seasonal movements of wildlife.

Three processes in one! Wildebeest near Naabi in Serengeti are gathering in the rainy season when surface water is drinkable to graze the nutrient rich grasslands of the short-grass plains. The impact of so many grazers is extreme!
Secondly, there's the impact of animals - grazing and browsing in particular. Savannahs are often full of animals - it's why people come to visit after all! And the impact of all those animals is not to be underestimated - take them away and the savannah can change dramatically from grasslands to woodlands and even (depending on the other processes) forest. Animal impacts can be seen all over the savannah and again, we'll visit these issues in subsequent posts.

Thirdly, there's fire. Savannahs burn and always have done so - today, many fires are deliberately set as part of the management, but people have probably been burning savannahs as long as there have been people around and before that lightning would have set fires naturally - probably about every 3-6 years we think. This is an ecosystem that has evolved with a constant presence of fire, the trees regrow, the grass regrows and (most) of the animals are perfectly capable of escaping fires by running or hiding in holes, etc. But fire frequency and intensity can certainly shape the savannah and it's a vitally important process to understand.

Finally, there are nutrients. Many savannahs are found on ancient and highly nutrient poor soils where every little patch of nutrients will be highly valued by something. Other areas are on recent volcanic and nutrient-rich soils, providing ideal grazing opportunities and different niches for vegetation types. Where nutrients are found (and how they get moved about) dramatically shapes the ecology of the savannah biome from the small scale of termite mounds to the larger scale of soil types, determining seasonal patterns of movement for animals and many of the habitat differences found from place to place.

And that's it! Future posts will develop all these issues further, but it's a great start in savannah ecology to have in mind the processes that shape the biome before we look too far at each one.

Welcome to Safari Ecology!

During two weeks of guide training in Tarangire National Park for Asilia we realised how useful it would be to keep the information flowing, offering safari guides in East Africa and other interested people the chance to continuously learn more about the ecology of the places visited on safari. We're hoping that between us we can blog about a whole range of things from interesting stories to tell about specific species, through a bit of geology, to articles developing a deeper understanding of the ecology that holds these ecosystems together.
Between us, we've experience both of professional safari guiding and academic research throughout East Africa, and we hope we'll also be able to persuade others to contribute their expertise to this blog too! Whatever your interest in the ecology of East Africa, we'd like to hear from you and suggestions of new topics to cover are particularly welcome (as will be offers to write them!), so please do comment. If we get enough interest from readers we'll keep this blog going - otherwise it will dwindle and fade into a quiet and dusty corner of the internet (we're busy people to other things to do too!).

In our guide training we covered the ecology of different habitats, stories about particular species and a list of things to talk about when the big five are being elusive. At least to start with, we'll be sticking with tags related to these main topics to manage the content. If you want to follow any particular part, use the labels on the sidebar to navigate.