Friday, 7 December 2012

Common birds (1)

Speckled Mousebird, Arusha. Cute, and really quite interesting...
OK, I've been away from here for too long (sorry!), but to encourage me to actually get down and do something, I've decided to start a new little mini-series here on common birds. As any of you who knows me is aware, I happen to rather like birds and will happy spend hours sitting wathing birds at a pond, or even trudging through kilometers of rift valley lakes to count waders. And I have a secret theory that actually, everyone loves birds, they just down all know it. The problem is that there are a lot of different birds out there (do watch Ethan as he tries to see as many as possible this year and records his exploits over here!), they often move rather fast, and people can be easily confused at first. So I thought we'd break it down into some very simple stages and try and start with 50 of the most common / obvious birds on safari or about towns in Tanzania. For each one my challenge is to briefly describe the key features to help you identify it, and then to say something interesting about it. If all goes well, I might even expand my remit to include non-birds, but we'll start with 50 common birds and see how that goes. Rather than throw it all at you in one go (and because there's no way I could write that much in one sitting!), I think I might try three species a post. It might also get a little interactive this way, if anyone wants to help me identify the top 50 species, that would be great,a nd if you've got your own preferred 'factoids' about any of the species, please do chip in!

So, let's start today, in no particular order, with the Speckled Mousebird.

Thursday, 1 November 2012

Ground Pangolins and Convergent Evolution

On a recent safari I was fortunate to get my first ever sighting of a Ground Pangolin. This animal is quite fascinating.
1.     What is it?

Kakakuona (Swahili) is a mammal that belongs to its own Order called Pholidota. It is a monophyletic order which means there is only one family Manidae.

2.     What is it doing?

Sunday, 2 September 2012

Cycads and more botanical revolutions I've missed...

Lake Natron Cycad, near Loliondo. Cycads look rather
palm-like, but are not true flowing plants at all.
Back in April I headed to Loliondo for a few days with a bunch of guides from Thompson Safaris. Along the long and bumpy route I was really pleased to spot some Cycads and jumped out to take a few photos. Spotted in action, I was forced to explain why I was taking pictures of some random tree. My answer at the time was based mainly on the evolutionary history of plants that I'd been taught at school and then probably on into university: Cycads form a remarkably early split from the branching evolutionary tree of seed-bearing plants, their ancestors somehow linking ferns to the much more modern flowering plants.  I was also keen to see this particular species (according to the IUCN commonly known as the Lake Natron Cycad) because it's one more of those remarkably restricted range species that fascinate me.

Now I have a confession to make - once again I was completely wrong!

Tuesday, 7 August 2012

Do fires stop the Serengeti migration?

Dr Kate Parr lighting a controlled fire in the Serengeti Ecosystem
There's been a bit in the East African press recently claiming that Tanzania has been deliberately setting fires in the Serengeti NP to block the migration. The Tanzanian National Park Authority (TANAPA) have, of course, denied this. Reading the articles and press releases there's obviously both some serious ignorance and some seriously bad journalism going on here, and I thought it might be useful to share a few of my observations.

Thursday, 14 June 2012

East African Butterfly families and corrupt, singing caterpillars

Citrus Swallowtail, Papilio demodocus, is very common in Tanzania
We're rarely short of butterflies in Tanzania, but they're a sadly overlooked group. Except, perhaps, when they're swarming by the million as earlier this year most people will, at best, only notice a few in passing. For a hugely diverse group (there are over 18,000 described species), they fall into a relatively small number of readily recognisable families. Unfortunately, all the nice identification books are out of print (and wickedly expensive to buy on ebay!) for East Africa, but there are some resources out there that will help once you've figured out the families. The relationships between the families have recently been the subject of some serious work. It turns out that the family relationship were rather difficult to pin down because they all evolved relatively quickly in the Cretaceous (yes, dinosaur time, 100 - 75 Million Year Ago). But our best guess at the moment sorts them into 4 main groups split into a total of 26ish main family groups, only a few of which are at all diverse. So it's not too hard to get to grips with the main families, and the main change to the traditional taxonomy, if you've been into that, is that the big group Papilionoidea is actually two, rather distantly related groups. I'm going to describe some of the common families here (together with some of my favourite stories about them - yes, including corrupt, singing caterpillars) and hopefully will be able to show how the various families fit together at the end. So, here goes...

Monday, 4 June 2012

More on management of protected areas: the human dimensions.

Public relations are a huge part of conservation work
In the previous post I described two of the ten lessons that we, a bunch of conservation managers and researchers from eastern and southern Africa identified at a workshop in Serengeti. I started with the big lessons on making sure you start with boundaries that make ecological sense - and what can happen particularly to migrations if that's not done. There's more to learn on that score too, but I'll skip to one of the most important lessons we identified, that will come as no surprise to anyone working in the field: don't neglect public relations!

Saturday, 2 June 2012

On managing protected areas...

Spot the scientists! Prizes for anyone who can name at least 4...
In  a very rare burst of finishing things of, I've managed to submit two papers this week (wow!). One is on climate impacts and I'll blog about it in time, the other is something I've been working on for a some time that reports the deliberations from a workshop that I was invited to 18 months ago now, at Sasakwa Lodge in the Grumeti Game Reserve. This was a fascinating experience, and not only because it's the only way the likes of me will ever get to stay in Paul Tudor Jones' house and be looked after like a real guest! We brought together several senior researchers and conservation practitioners from Tanzania and Southern Africa, to see what would happen. And what did happen (as well as the lodge running out of whisky), was an attempt to identify the ten most important lessons for conservation that could be learnt from the mistakes of southern Africa. As they say, it's a wise man who learns from his mistakes, but it's an even wiser one who learns from the mistakes of others! So, given that the population pressures in east Africa are now similar to those experienced in southern Africa when lots of conservation interventions started to happen down there, we thought it would be a good time to see what we could learn.

Thursday, 31 May 2012

Why do scorpions fluoresce and other such trivia...

Scorpions - everyone's favourite!
I have to admit that I find scorpions a bit creepy. Not only do they have too many legs to begin with, but some of them seem to accelerate from stationary to far too fast in no time at all. And, of course, some of them (a tiny minority, it's true) can be really rather nasty when they're pushed to it. However, despite the slight wariness they inspire in me, I do find them absolutely fascinating creatures. One of the big things that puzzled me about them was their bizarre fluorescence under ultra-violet light. If you've never been it, it's well well finding someone who's got a fluorescent light and taking them to the bush at night. You'll be amazed not only at how the beasties glow, but by quite how many of them there are! In many savanna habitats you'll see them every 3 or 4 metres. Hopefully enough to convince you never to walk in the dark without shoes! Why they should do this has been a mystery to me, but some new research published this year by Gaffin et al (find it here, but you have to pay...) has, perhaps, started to unravel the mystery.

Friday, 18 May 2012

The big burn...

So, I promised more details would come, so here goes with some more background and some of the detailed plans I've got to burn Serengeti. If you like what you see don't forget to support the project over here!

There are few active management activities taking place in most of East Africa's protected areas – a policy that has so far proved fairly effective at managing functioning ecosystems. However, one of the management activities that does happen in many areas, is burning. Fire is generally considered a vital component of savannah ecology, with trees, grasses and animals all adapted to a fire prone ecosystem: in fact, globally, 85% of fires occur in savannah habitats. In most of Tanzania's protected areas, rangers deliberately set fires each year for a number of different purposes, including the encouragement of new grass growth for grazers and the control of bush spread. Recent evidence from a global study suggests that at least for those savannahs occurring in areas with over 1000 mm of rainfall, the forest/savannah edge is often maintained primarily by fire, and that in its absence many savannahs will revert to forest. There is some debate, however, about whether grazing and browsing alone may provide an equivalent process when animals are at particularly high densities, with the result that the benefits of fire in certain areas have been questioned. For example, in some areas of Tarangire National Park with high numbers of migrant animals during the dry season, fire has been totally suppressed for over 30 years with relatively little obvious difference in grass and tree cover between fire-suppressed and more frequently burnt areas: it is argued that in the burnt areas fire simply burns potential animal forage. Similarly, in Kenya, the Kenya Wildlife Service has recently instigated an overall policy of fire suppression except where the fire is caused by natural events (essentially, lightening storms) in an attempt to encourage one view of naturalness. There are, of course, alternatives to these two extremes, where fire is sometimes suppressed and sometimes encouraged. Given that fire is one of very few activities conducted by management in these areas it seems sensible to understand more fully the consequences of these different management decisions.

Traditionally, pastoralist communities in northern Tanzania have set fires towards the end of the dry season, in anticipation of the rains. They make a calculated gamble between burning possibly useful forage if the rains are delayed, and waiting too long and being unable to burn (and encourage the new growth that will come with the rains) if the rain comes before they have time to burn. Obviously, by this time of the year grazing animals will already have reduced fuel loads to relatively low levels in many areas, so late dry season fires will only occur in less grazed areas, with other areas remaining unburnt. Such management was also the norm in many protected areas (including Serengeti) until around 1970, when concern over the regeneration of trees prompted a switch in fire management towards controlled burns in the early dry season (mainly in June). Such fires are generally cooler and patchier, with possibly less impact on woody plants. They also prevent the late season burns that are likely to be hotter and less easy to control with consequent reduced concerns about tourism infrastructure. Recently, managers of the Grumeti Reserves in western Serengeti have attempted to suppress early season fires, only allowing burns later in the dry season (from late July), allowing the migrant wildebeest and zebra to graze unburnt areas and increasing the forage available to these animals to the extent that their residence times within the reserves have tripled. Fires are also set during the short dry season, in February, and grass growth rates are such that some areas of the national park burn twice per year. Observations suggest that areas burnt in February may be preferred by migrant ungulates during June, but beyond these patterns and the immediate, short-term responses of grazing animals, we understand relatively little about how fire impacts the ecology of Serengeti or other East African protected areas in the bimodal rainfall area. Whilst we know a little about the impacts on large mammals and early vegetation responses, we know almost nothing about the impacts on other taxa, or the soil fauna and nutrient flows of the savannah ecosystem.

In practice, over much of Serengeti, fires occur once or twice per year. If there are species within the ecosystem that are rather more sensitive to fire than others – for example, ground nesting birds, toutoises or various plant species – such frequent fires may have negative impacts on the population. On the other hand, burning in different seasons may affect different species in different ways. Whilst it is generally considered 'a good thing' to burn Serengeti whenever it can burn, maybe reducing this frequency doesn't actually have the negative impacts expected and could, instead, benefit other taxa not usually considered in protected area management plans? How many unburnt seasons does it take before grass quality starts to decline? Would a general switch back to late-season burning be beneficial? The only way to answer these various questions is a detailed, but large-scale study of fire impacts in the Serengeti ecosystem. To date, there have been a few relatively small scale and short-term fire experiments in the ecosystem, there have also been longer-term but equally small scale studies in other African savannah systems. Both have provided insights into the management of fire in these systems, but only in Australia (where herbivory plays a completely different role) have experiments been carried out on a large scale in savannah ecosystems, providing a different range of insights to those of small scale experiments. Large-scale and long-term management trials in an area of bimodal rainfall will provide insights of relevance not only for the Serengeti ecosystem, but also for savannah ecology in general.

So, what am I actually planning to do? It's all fairly applied. My aims are (I hope) clear:
  1. To understand the impacts of alternative fire management options on the ecology (both pattern and process) of the Serengeti ecosystem
  2. To be able to inform managers on the best way to use fire as a management tool to achieve their stated aims.
  3. To understand the importance of fire and grazing in shaping the ecology of the Serengeti ecosystem across the rainfall gradient.
So it's really a very applied experiment: I want to change burning patterns from what could be currently descirbed as 'burn-if-you-can' to a number of alternative strategies that are also perfectly manageable for the ranger in the field:

Frequency treatments:
'Maximal burn': corresponding to a burn-if-you-can treatment as carried out across much of the National Park, with fires set whenever possible.
'Hold-back': corresponding to a management regime that notes when burning would be possible but delays by one or two seasons until fuel loads are higher.
'Minimum burn': corresponding to a management regime that attempts to suppress fire return rates to 4-5 years, a frequency that has been suggested to be suitable for recovery of riverine forest and thickets.
Seasonal treatments:
'Early burn': corresponding to the long dry season management regime across most of the National Park, where fires in the long dry season will be permitted at the end of the rainy season – in northern and western areas of Serengeti (e.g. the western corridor) this will be before the migration arrives.
'Late burn': corresponding to the type of management traditionally carried out by pastoralist communities, with fire suppression during the first part of the long dry season and burning set in anticipation of the rains.
'February burn': corresponding to areas where management will attempt to burn in the short dry season and suppress fires in the long dry season (only northern and western Serengeti).

And where will we be doing this? Well, the study sites are burn management units within the TGT concessions of Maswa Game Reserve, within the Mwiba Holdings private concession around Makau Village and on Grumeti and Ikorongo Game Reserves and the adjoining Wildlife Management Area. These areas include a near complete range of Serengeti ecosystem habitats and rainfall gradients, from dry Acacia – Commiphora woodland and short grass plains in Mwiba Ranch, to Terminalia - Combretum woodlands and tall Themida grasslands in the Ikorongo and Grumeti Game Reserves. In total, the area managed within these three reserves is in excess of 2700km2 (270,000ha), making this study easily one of the largest experiments in the world. Burning blocks within each reserve will be assigned to fire treatment, stratifying for size and rainfall across the entire set of study areas.

In addition to the experimental work in the reserves surrounding the Serengeti National Park, we will conduct similar monitoring activities at sites within the National Park, to ensure that the 'maximum burn' treatments within the experimental areas show ecological dynamics similar to those within the National Park.

So, hope that fills you in with lots of details! If you've got this far you're obviously really, really interested so please do go to the project page and support us! Every little bit helps...

Tuesday, 15 May 2012

Breaking the silence...

Hello everyone, and apologies for being offline for so long! I've been running around like a mad thing - Manyara, Loliondo, Ndutu, Cape Town, you name it, I've been there! I'm now back home and full of ideas for lots of new posts to keep things rolling. Whilst I sort out my photos and 1000s of emails I thought I'd bring to people's attention one thing I'm up to next. Regular readers will know I have a thing about fire in savannas and may even have picked up my plans to do a large-scale burning experiment around the Serengeti NP (I mentioned it here...). Well, the project has been officially approved and will be happening, but we're trying to raise some money to help get started and we're trying out crowdfunding as an experiment. What's crowdfunding you ask? Go and find out here! Using the newly set up website called Petridish, we're trying to get some start up funds in the next few weeks - there's opportunities for anyone to donate online, any amount, and some fun rewards to donors too! There are loads of other projects all looking for funding on the Petridish site, so we need to get some momentum going and then the site will push us harder too. I'll post some of the rationale for the experiment and more details here soon, but please do spread work about this and make a donation, however small, as soon as possible! There's a deadline on donations, and if we don't get the money we've asked for by then all the money goes back to the donors... Launching today, we've still got a long way to go! So, share the word, donate and (if you can bear it) watch me explain the project on the little video!

Here's the link to read about the project, see the pictures and video and make a donation. Thanks!

Tuesday, 3 April 2012

African Vulture Declines

I saw this hooded vulture in Tarangire this weekend, so they are still around!
I've spent a bit of time over the last few days analysing some of the data from the Tanzania Bird Atlas project on vulture declines in advance of a workshop happening soon in the Maasai Mara. The Asian vulture decline is quite possibly the fastest decline in any bird species ever recorded, with more than 95% of the Indian population of Oriental White-backed Vultures dying between 1988 and 1999, from one of the commonest large raptors in the world to one of the rarest. It's now well know that the cause of that decline with the veterinary use of a drug called Diclofenac which, happily, isn't in quite the same usage here in Africa - sick o dying cows tend to be eaten here, not treated with drugs and then left for the vultures. But although the declines haven't been as steep and there are still plenty of vultures in places here in East Africa, there's still a problem.

Monday, 2 April 2012

100th post!

Safari Ecology comes of age with this, it's 100th post! It seemed like a useful moment to review progress so far.

We set out to be a resource primarily for guides in East Africa, posting things about the ecology of the area and recent scientific studies that might make for useful or interesting information. With that primary purpose in mind it makes sense to announce that Ethan has organised a whole set of new guide training activities for April and May - as well as the obvious comprehensive 6ish week training course on natural history, ecology and the like, there are courses on first aid, psychology for guides and others too! The course should be suitable for anyone with a bit of guiding experience and should get you to a level that, once the syllabus is finalised, will be ready for testing under the new Tanzanian guiding standard that's being developed. Check the dates and things here and if you want to know more contact Ethan directly.
Daily visitors from the three top continents: Blue = Americans, Red = Europe, Green  = Africa

Friday, 30 March 2012

Revising climate impacts on African vertebrates

A few weeks ago I wrote a piece on climate change and African vertebrates. As I usually do, and especially in this case as Raquel had pointed the paper out to me, I let her know that I'd written something and asked her opinion. After quite a few emails back and forth we confirmed that I'd misunderstood a figure in the paper that I'd thought was the crux of the matter, but it turns out to have been not as useful at all.In light of these discussions, Raquel and colleagues have now produced an addendum to their paper that contains the figure I thought I was looking at and, although I still have some issues with the work, it makes much more sense to me now! In the interests of getting all this information out there, as well as my pointing out the mistakes in the original post and Raquel posting a comment there, I thought her ideas were valuable enough to reprint in full from the comment as a new post, with some more discussion here. So, here's what she has to say:

Wednesday, 28 March 2012

On cattle in African protected areas

Typical pastoralist scene near Lake Eyasi
Talking about blog topics the other day, a friend asked me about the impact of goats and cattle on wildlife. And then over here someone else started a similar discussion on cattle, which collected a wealth of different ideas, so I thought it would be a good idea to collate all this information for a different audience over here. Increasingly, discussions about cattle come up when people are visiting areas that aren't National Parks - here in Tanzania many people are surprised to see cattle (and their Maasai herders) right in the Ngorongoro crater, as well as around the rest of the NCA. And increasingly (particularly in Kenya where land laws make it much easier, but also here in places like Manyara Ranch) conservancies are being set up where communities set aside land for both wildlife and pastoralist activities. The fact that organisations like the Northern Rangelands Trust are making a real success of this, combined with ongoing concerns about displaced people and human rights issues, has encouraged people to think seriously again about whether the strict 'no people' policy of many national parks in Africa might be relaxed, and recognising this a few years ago the International Conservation Union (IUCN) relaxed their national park category definition to allow management "To take into account the needs of indigenous people and local communities, including subsistence resource use, in so far as these will not adversely affect the primary management objective". So, what are the issues here, and what are the ecological arguments? In this post I'm going to deal with cattle, and leave the goats and sheep for a future occasion.

Monday, 26 March 2012

Why do savanna trees have flat tops?

Umbrella Thorn, Serengeti: An icon of the savanna?
From sunsets behind a silhouetted acacia (properly Vachellia), to photos of rolling grasslands studded with isolated trees, a savanna landscape is immediately identifiable thanks to the flat-topped tree. But why is this? Why do so many Vachellia and other savanna trees have such a distinctive structure that they have become a virtual icon of the African savanna?

It's an interesting question that was given some answers in a nice paper by Sally Archibald and William Bond who studied one species called the Sweet Thorn (Vachellia karroo) that, rather like some of our Vachellia species in East Africa exhibits a range of different growth forms in different habitats. In the semi-desert of the Karroo, it grows as a medium-sized ball of thorns, whereas in the savanna it has a fairly typical medium-tall  flat-topped acacia look to it and in a forest it's a tall, thin tree. These differences are meditated mainly by genetic differences within the species, but equally could be caused in other species by a variable response to the environment - it's not really important to this discussion and, in fact, much of our discussion could focus on different species if we wanted. As always when we're thinking about what makes the savanna species, we'd be well advised to start with the savanna big four: nutrients, water availability, fire and herbivory.Now, the first two processes have impacts in all biomes, whereas it's the second two that are most distinctive about savanna and where we'll start our discussion.

Friday, 23 March 2012

Ecology for safari guides

This blog was set up originally to be a resource for safari guides around east Africa, and I hope it still fills that purpose. (We're coming up to 100 posts soon, so that might be a suitable moment to see how well we're doing...) Over the last couple of weeks we've been talking with a bunch of folk about forming a society for Interpretive Guides which could develop and maintain a qualification for guides in Tanzania - at the moment there's nothing widely recognised in the industry. With the assistance of the PAMS foundation, we're collecting syllabuses and guiding standards from around Africa and trying to develop something that may be seen as defining 'best practice' for guides in the region. As part of this process I've been putting together the things that I consider guides should know about ecology, and I thought it might be interesting to post the rough ideas I've got here for comments. There's much more that will go into the syllabus of course, this is just going to help contribute to the ecology module we're putting together, there's got to be lots more natural history modules in the course, covering mammals, birds, reptiles, plants and all the rest. And there's also likely to be as much about guiding ethics, psychology of groups, etiquette, etc., as well as the hard skills like proper driving, first aid  and (if you're walking) firearms. So don't worry about those bits just now, I'm just doing the ecology bits.

Wednesday, 21 March 2012

Why is snake venom so toxic?

Puff-adders probably cause more human snake-bites than any other African
snake, but are rarely fatal. This is a juvenile, but don't think it's harmless.
After discovering all the amazing things about pedarin and the 'Nairobi Eye' last week, it set me thinking again about why so much wildlife is so incredibly toxic. Think about it - a little beetle small enough to crawl over you without you noticing at all, is more than toxic enough to kill a grown man - indeed, several. A snake like a black mamba can give a bite that's sufficient in toxicity and volume to kill an adult elephant. Many natural venoms aren't simply one chemical, but a mixture of nasty toxins with a whole range of activities - why go to the trouble of evolving a whole suite of nasty chemicals, when one is usually enough to kill most things? Why should it be so toxic? What's the purpose?

Monday, 19 March 2012

Distribution of Ethiopian Bush-crow and the nature of explanations

Yesterday I was sent a link to a press release from the excellent BirdLife International (read it here). It's talking about some research by an international team to try and explain the remarkably restricted range of the Ethiopian Bush-crow (cute picture here, since I've never actually been there to take my own), and in it, Paul Donald the lead author makes some interesting comments:

“The mystery surrounding this bird and its odd behaviour has stumped scientists for decades – many have looked and failed to find an answer.  But the reason they failed, we now believe, is that they were looking for a barrier invisible to the human eye, like a glass wall. Inside the ‘climate bubble’, where the average temperature is less than 20°C, the bush-crow is almost everywhere.  Outside, where the average temperature hits 20°C or more, there are no bush-crows at all.  A cool bird, that appears to like staying that way.”

The reason this species is so completely trapped inside its little bubble is as yet unknown, but it seems likely that it is physically limited by temperature – either the adults, or more likely its chicks, simply cannot survive outside the bubble, even though there are thousands of square miles of identical habitat all around.

BirdLife International’s Dr Nigel Collar is co-author of the study. He added “Whatever the reason this bird is confined to a bubble, alarm bells are now ringing loudly.  The storm of climate change threatens to swamp the bush-crow’s little climatic lifeboat – and once it’s gone, it’s gone for good.”

Tuesday, 13 March 2012

How do Kopjes form?

It's a question I regularly get asked by guides and also one that seems to bring a lot of google-searching visitors to the site, but I've not actually posted much of an answer yet although we have covered it briefly here, so here goes...

Cross-section through a kopje in the process of formation
from smooth, uninterrupted landscape at the top to
typical kopje at bottom, following millions upon
millions of years of erosion.
We start by remembering that Africa is old - most of the surface rocks are pretty ancient (and consequently washed clean of most nutrients - an issue we've talked about repeatedly). During these millenia, mountains have been formed and then worn down to small hills, whilst the valleys, plains lakes and seas have been buried in the sands and gravels of this erosion process. Over time and with immense pressure these sands and muds too have sometimes been 'recycled' into sandstones and mudstones in someplaces. It's not just been static though: later volcanic events sometimes push magma (un-errupted lava) through the layers of rock towards the surface where it cooled and formed an intrusion of new rock within a mass of older layers. (As shown in the diagram!)

Monday, 12 March 2012

Why do birds sing in the morning?

Ruppell's Robin-chat: an impressive mimic. Lake Duluti
I enjoyed a walk around Lake Duluti yesterday morning and came across a couple of wonderfully singing Ruppell's Robin-chats. These are great birds, with an amazingly varied song hat's gull of mimicry (of you want to hear one, listen here!). For me, one of the best things about camping in the bush is being able to lie in bed and listen to the birds waking up while it's still too dim to see them properly. The dawn chorus is a worldwide phenomenon and I'm often asked about bird song, so I thought it would be worth exploring some of the theories behind bird song, and - particularly - why birds sing in the morning. It's something that's interested me since I was introduced to the question by a friend of mine who did a PhD on the subject some years ago, and I know he reads the blog so I'm hoping he'll make sure I get the answers right!

Thursday, 8 March 2012

Lewa Downs wildlife corridor really works!

As regular readers will have realised, I'm something of a sceptic about most things, and one of the things that I've been pretty sceptical about in the past is wildlife corridors. They sound like a great idea: wild spaces are increasingly fragmented (even here in East Africa), and as that process continues populations of plants and animals within these areas will become increasingly isolated from one another. Isolated and small populations are more likely to go extinct than large, well connected populations for a number of reasons ranging from inbreeding - in small populations you're rather more likely to have to mate with a brother or sister than in a large population, which can have serious genetic costs, to simply the risk of extreme events wiping everything out. So connecting those fragments with corridors along which animals can pass seems like a really good idea. Tiny experiments using micro-ecosystems where no-one cares if you isolate populations or connect them seemed to suggest that there might be something in this idea, and all of a sudden conservation corridors were high on the agenda.

Tuesday, 6 March 2012

Nairobi bugs: WMD or Cancer cure?!

15 times more toxic than cobra venom, you really shouldn't eat a Nairobi beetle!
Nairobi bugs (also known around East Africa as Nairobi Eye, Nairobi Fly, Nairobi beetles, Blister Beetles and a whole range of other names) are not the best loved creatures out here. This year they've come out in greater number than the last few years, presumably thanks to some relatively good rains, and whilst they're not loved, they're certainly fascinating wee beasties. But before we go into the details, let's start with some identification preliminaries.

There are actually at least two species of beetle known as Nairobi bugs around here, but they're so similar that most people won't notice them. Similarly marked relatives of these two are pretty widely distributed across the world, mainly in the tropics, and for now I don't think we need to bother about the precise identification. They're all small (7mm-1cm ish) and well marked with typical warning (aposematic) colours of black and red. In fact, despite the variety of names these are beetles (Coleopterans) of the family Staphylinidae, the rove beetles. If you don't know the Nairobi beetle, you might well know the Devil's Coach-horse and similar species - much larger and all black, but of a similar basic structure. The beetles we're interested in are of the genus Paederus and are carnivorous beetles that live mostly in long grass and anywhere with rotting leaves. And the most interesting things about them, as anyone will tell you, is that whilst they neither bite nor sting, they're still seriously nasty.

Sunday, 4 March 2012

Migrant bird population declines, an African perspective

Willow warbler singing in Africa - 10g but probably headed to eastern Siberia...
March is the month when northward migration of songbirds gets underway in East Africa, so this weekend I was excited to be out west of Arusha with friends and to find stacks of migrants already on the move. Driving in I noticed some really smart looking wheatears (both pied, and the very impressive northern wheatear, though many of them have already set off on their mammoth treck - perhaps as far as Alaska). But the highlight for me was the bushes alive with warblers on Saturday morning. I saw flocks of Willow Warblers, Olivaceous Warblers, Common Whitethroats and even little groups of Barred Warblers, usually a very scarce migrant around here. Some of them were even singing, in anticipation of starting breeding in a few more weeks when they get back to Europe! Having a managed a few photos I thought it the ideal opportunity to talk about bird migration.

Barred warblers are always a treat to see: headed to eastern Europe.
All these birds have been rather scarce until now, this season, and many of us have been wondering where they've got to - usually Willow Warblers and Olivaceous Warblers are one of the commonest birds in the bush from November to March, this year there have hardly been any. It's a question that will be familiar to many readers from Europe - where have the migrant birds gone? Research has suggested over the last few years that in Europe at least, migrant birds are declining faster than resident species, a change that has been attributed mainly to climate change. A number of theories have been put forward to explain why migrant birds may fare worse than resident species from the impacts of climate change - from them simply missing the peak spring food availability by arriving to late in Europe as springs get warmer (and therefore earlier), to direct effects of drought or land-use change in Africa. A recent paper (sorry, not free) has attempted to look into some of these likely causes using data on breeding population changes in the UK, and it serves as a nice bit of background to some of the remarkable things that birds do when they set off on their amazing migrations.

Thursday, 1 March 2012

The role of termites in the savanna biome

The ground is crawling with termites! Nr. Tarangire, Now 2011.
Termites are hugely important to the of the savanna biome. We've covered some of their roles here before when we talked about termite mounds and when we covered nutrients and nitrogen in the savanna biome. The numbers of termites in savanna habitats can be quite extraordinary: with over 400/m2 of soil, their biomass can exceed that of mammals in the ecosystem. Such a huge abundance of animals mean that termites, by weight of numbers alone, must have a massive impact on the ecosystem. We've seen how they are crucial for keeping nutrients cycling rapidly in the savanna, how their excavations can change the texture of the soil and how these impacts change the plants and, ultimately, the behaviour of animals within the savanna. Despite this obvious importance, however, there's surprisingly little research on what they actually get up to and where they really are - I guess researchers are generally too busy tracking lions sleeping under a bush than worrying about termites under their feet... It's important though, as processes that cause spatial variation in patterns of nutrients and such-like are increasingly being perceived as vital to the ecosystem as a whole, and if we don't understand the processes that cause variation, it will be much harder to understand what's going on at larger levels. Still, some work is coming out now, and a paper last year caught my eye.

Tuesday, 28 February 2012

Exercise like a lion!

Wildebeest wrestling - the ultimate fitness regime? Selous GR, June 2010.
I came across a paper this last week - I can't remember how, because it's certainly not my usual reading material (though my wife has just pointed out a report on the BBC today) - but it suggested an answer to one of the things that puzzle me about lions. Like most cats, lions like to sleep. A lot, in fact - they're perfectly content sleeping for 21hrs a day, so it's no wonder tourists don't normally see them doing very much. As a consequence, I think lions are rather boring: I'd rather be birding. Still, on the occasions when I've got visitors staying who need to see lions I do go and look at them, sleeping away, and I wonder. How is it that a lion, sleeping 21hrs per day, can still be so fit and healthy? On the rare occasions when they do shift themselves, wild lions are certainly lean, mean killing machines. But how do they remain in such good condition, when they sleep nearly all the time, and even when hunting tend to walk as slowly as possible, or sit motionless in ambush?

Saturday, 25 February 2012

Commelina, the Maasai Reconciliation Grass

Commelina sp, Mongo wa Mono, March 2011
It's surprisingly easy these days to find information on the medicinal use of plants (there's a great list for the Samuru people here, for example), such as the Commiphora uses we covered last week, but many plants have cultural significance beyond the simple medicinal uses and it's often much harder to find information about these uses. One of the 10 things I like to get people talking about when there are no lions is all to do with people, and talking about cultural uses of plants is often quite interesting. I was seriously impressed when one of the guides on our training course in November said that in 'circumcisim school' he'd had to learn to identify about 200 plant species and know their cultural and medicinal uses, so this knowledge is still very much alive out here - though he did confess to having forgotten many (before going on to hive an example of a rather harrowing use for one of the Euphorbia species that really isn't suitable for polite company...). So it's rather surprising how shy people can be about sharing the information, perhaps thinking it's not interesting, or somehow backward.

Tuesday, 21 February 2012

Why the hornbill shuts its nest

Von der Decken Hornbill nest cavity - it's tiny!
 This weekend I enjoyed a camping trip out to Simanjiro with some friends, and as well as finding some very cute new-born wildebeest, we found a number of nests. One of these, just near our campsite, was a pair of Von der Decken's Hornbill. All the hornbills of the genus Tockus have two fascinating pieces of nesting behaviour that it's well worth thinking about: firstly, after choosing (and sometimes modifying) a suitable nest cavity, the female climb inside and then plugs the nest hole with mud, faeces and other grot, sealing herself in until there's only a tiny slit through which the male feeds her and, later, her chicks. Secondly, as she's sitting there she carries out a simultaneous moult, meaning she drops all her flight feathers at once and is unable to fly. Nearly all birds moult their feathers once per year (larger birds sometimes take longer), but most do a sequential moult, meaning they drop feathers one after the other and replace them as they go, thus retaining the ability to fly throughout. (There are exceptions, of course - notably ducks and geese who also drop all their flight feathers at once.) In the case of the female hornbill, however, she goes in the nest hole, shuts the door and a little while later drops all her flight feathers. Interestingly, if she doesn't breed, she moults sequentially, just like the male, so there's some suggestion that the simultaneous moult strategy is triggered as a hormonal response to the dark interior of the nest. Now, that's the story that you'll read in all the papers (e.g. here and here), but it can't be the whole story as I was trying to find some pictures to point you to of birds inside nests looking all naked, and I couldn't. In fact, here are a few pictures that show females in the nest - this one is an African Grey Hornbill with smallish chicks, but clearly well feathered mother with fairly worn plumage - she's not just completed a moult. And here's an Asian species also with young chicks who certainly doesn't look in moult to me. I'm sure it happens though, and may be the norm, but there are obviously exceptions that haven't yet made it into the literature.

Sunday, 19 February 2012

Threats and opportunities of the bushmeat trade

Snared giraffe, Serengeti NP Jan 2011. A major target right now
Following my post a while back about Dennis Rentsch's work on the bushmeat trade around Serengeti, Matt asked me to cover this issue in a bit more depth. (Though if you want to see how it's possible to have a sustainable harvest of around 100,000 wildebeest per year from Serengeti, with a net value of $2.5-$8.5 Million per year check the original post here!) And there've been a number of interesting papers recently that have started to fill in some details. It's not a subject I've much experience of, so I'm skimming the surface a bit, but I think it might at least highlight some of the issues involved.

We'll start with the caveats. Understanding the bushmeat trade is tricky - in most places it's illegal, and people aren't always going to talk freely. And if they do talk, there's a good chance they won't tell you the truth either - they might either say they do less hunting than they really do to play down the impact, or they might go down the macho route and tell you they're excellent hunters and never come back without a pile of buffalo, etc... Dennis's work took an alternative strategy, instead of asking the poachers to tell him what they hunted, asking the villagers to tell him how much bushmeat they consumed and working back to the harvest that way. Others have worked on data using poacher arrests, viewing this as an index of poaching activity - though there's no way to tell what proportion of poachers get away with it (what poacher, when arrested, will really tell you how often they've been poaching before and not been caught?!). The only comparison between these three methods is Dennis' and that suggests that measuring consumption gives a poaching pressure that parallels that from arrest records, but neither of these fit with pressure as assessed by poacher interviews. That suggests to me that Dennis' work is probably the most accurate, but he's not yet published these studies, so for now you can only read about it here. The vast majority of other work is based on poacher surveys, and we also know that when you compare what poachers say the meat is with what the DNA tells you, you get remarkably little agreement too.All of this suggests to me that we need to take the research based on poacher surveys with a large pinch of salt. So, with that in mind,  I'm going to focus more on the declines that are reported to be associated with bushmeat, rather than the more poacher-based surveys.

Thursday, 16 February 2012

Myrrh trees (Commiphora) are useful things...

Most Commiphora have distinctive peeling bark, Eyasi Aug 2011.
Having last week given you the bad news about the biological warfare that plants with thorns are engaging in, I thought it only fair to share some tips that may help you stave off those tropical nasties threatening to kill you... So the good news is that some of those very same thorny trees that are out to get you also hold the cure in their sap. Traditional healers and many folk still living in the country have long known about the beneficial effects of the sap of Commiphora trees. Indeed, the earliest recorded use of Commiphora to treat infections goes back to 1100BC where Sumerians were recorded using myrrh (for that is what Commiphora is) to treat tooth infections and intestinal worms. It's use is also clear in the Bible, as one of the three famous gifts presented to the infant Jesus. Today it's still commonly used in village communities to treat an endless list of infections and maladies, and it's also pretty good as a mosquito repellant if you need emergency cover!

Wednesday, 15 February 2012

The wheatear's remarkable migration: Alaska to East Africa

A great piece of research came my way today, detailing the migration of the individual wheatears from their Alaskan breeding areas to winter territories in East Africa. We've long known this must happen, as pretty much all the world's Northern Wheatears Oenanthe oenanthe spend the winter in Africa, but now technology has allowed us to follow individual birds on their 14,600km long migration from Alaska to East Africa and back. It's a remarkable story, not least that a 20g songbird can repeatedly do this sort of movement, but that we now have devices that can be attached to such small birds and record their journey. Wheatears are also a favourite of mine, and their migration has been the subject of one of my student's research so I almost feel qualified to make a few comments!
Migration routes and wintering grounds of three northern wheatears breeding in Alaskan (AK) and one in the eastern Canadian Arctic (CN; grey dot, breeding area, blue, autumn migration, orange, spring migration, dashed lines indicate uncertainty in migration routes close to equinoxes). Fifty per cent kernel densities of winter fixes (beginning of December 2009-end of February; purple, bird AK-1; green, bird AK-2; orange, bird AK-3; blue, bird CN-1) are given depending on the sun elevation selected (with 228 for most southern and with 24.58 for most northern densities). Pie charts indicate the proportion of individuals (AK: n 1/4 9, CN: n 1/4 4) originating from one of the three pre-defined wintering regions (red, western; orange, central; yellow, eastern) [8] based on stable-hydrogen isotope (dD) values in winter grown feathers and the dD values within each wintering region (mean+s.d. shown); Credit: F. Bairlein et al. 'Global migration of wheatears' (doi:10.1098/rsbl.2011.1223) in Biology Letters

Tuesday, 14 February 2012

Tarangire wildebeest migration

Tarangire wildebeest on the move, Sep 2011.
Following the ATBC / SCB conference in June I mentioned a talk by Thomas Morrison on the movements of the wildebeest in Tarangire. The Tarangire migrations is, of course, tiny in comparison to the better known Serengeti migration and involves a different race of wildebeest (C. t. mearnsi in Serengeti, C. t. albojubatus in Tarangire) , but it's just as interesting to understand, and Tom and his supervisor Doug have recently published some work describing the movement that was covered in the conference talk. Until fairly recently, Tarangire was home to a large wildebeest population, though only around 6000 remain today. It's still one of my favourite places to visit though... These animals move into Tarangire in the main dry season (arriving in June) and then move out to one of two main areas for the wet season either east onto the Simanjiro plains, or north-west towards lake Natron. As with the Serengeti migration, these wet season movements are onto grasslands growing on recent volacanic soils with high nutrient content and just what is needed during late pregnancy, then when lactating after calving in February. One of the mysteries, however, is whether the population that moves to Simanjiro is the same as that moving to Natron - do the animals go one direction one year, and the other the next? And as those moving to Natron pass close to another population in Manyara, do those Manyara animals also join the movement? It's important to know the answers to these questions if we're to try and protect the animals, given that they spend around six months of the year outside the National Park system.

Sunday, 12 February 2012

On introducing elephants to Australia...

Sometimes scientists suggest the most absurd things. In the news last week (with thanks to an Australian friend for tipping me off) was a paper published in the prestigious journal Nature that suggested in the text and headline that Australia should introduce elephants to control an invasive grass that originally came from Africa: Gamba grass, Andropogon guyanus. The author made a number of sound observations: Australia (like too much of the world) is riddled with invasive species, has suffered a massive extinction of it's native mammal population and has had some pretty nasty wildfires in the last few years. But how you get from those observations to suggesting elephants (and even rhinos) should be introduced to the savannas of Australia is a story worth looking into.

Friday, 10 February 2012

Butterflies moving again...

Well, the initial movement seems to have petered out, with nothing major in Arusha and most other northern Tanzania areas since Sunday. But starting last weekend I started hearing word of movement down on the coast, and then in Kenya, around Nairobi and Mt Kenya areas, all of butterflies headed south. The last couple of days I've been hearing about massive movements - at least as impressive as the original movements over the Pare Mts (around 400/min over a 20m line!) and in much of Kenya (but the Kenyan's haven't yet given me anything specific enough to actually map - come on!). These animals now seem to have arrived more widely in Tanzania, with arrivals in northern Serengeti reported for the first time now, as well as continued movement on the coast. And there are even a few trickling over Ilboru again now - though we're clouding up here and I'm not expecting much. But if you've been following the story, please keep your eyes open and keep reporting. Here's the latest map. Please do encourage your friends and contacts to get involved. (And I'd still love to know what happened around Singida to the original movement!)

View Butterfly eruption 2012 in a larger map

Thursday, 9 February 2012

Why is the African Savanna so full of thorns?

Giraffe lick leaves between thorns. Note how obvious the white thorns are.
Spinescence. Now there's a word! It simply means having spines and one of the first things many visitors to the African savannah notice is that everything is covered in thorns. Or, in other words, Africa is spinescent. It's not a wise idea to brush past a bush when you're walking, and you certainly want to keep arms and legs inside a car through narrow tracks. These are thorns that puncture heavy-duty car tyres, let alone delicate skin. But why is the savanna so much thornier than many of the places visitors come from? Or even than other biomes within Africa, such as the forests?

This post I've just written as a guest blog over at "Nothing in Biology Makes Sense". I'm incuding it here too, but do go and check that blog out if you're interested in evolution! You can read the rest here, so skip to the story there if you want...

How the zebra got his stripes?

 Most animals in the savanna come in one shade of brown or another, except for zebra. Zebra, as everyone knows, are stripey. Black with white stripes, at that; or are they white with black stripes? Anyway, why they're stripey has puzzled many people for a very long time: even Wallace and Darwin debated whether zebra stripes make them conspicuous or not! For stripes to have evolved there must be some evolutionary advantage, but what, exactly is it? There are a huge number of theories out there (many reviewed here), from the rather obvious to the some more ingenious ideas too:

Wednesday, 8 February 2012

Climate change and African vertebrates

Last year I spent a very happy evening in Cape Town enjoying some of the local specialities with a colleague and a visiting student. Or at least, that's what I thought - poor Raquel now tells me I was giving her a hard time... Still, good practice for her eventual defence of her thesis I hope. Anyway, she pointed me in the direction of the paper she was writing at the time that's now out and attempts to describe what's going to happen to some 2723 species of African vertebrates as the climate changes over the next several decades. Now, despite climate change being a huge conservation issue and one of my main research interests (and climate/weather being one of my 10 things to talk about), we've not talked much about it here on the blog before, so the chance to discuss what might happen to 2723 species across the continent as a whole is an ideal opportunity to start!

Sunday, 5 February 2012

Notes on a butterfly eruption: a billion and counting!

 Just a brief post with the latest news, as it's coming in. The bulk of the movement seems to have passed Arusha Moshi now - there are still large numbers going through but (a) they've turned South West in most areas, and (b) they're coming through in groups now, not as a continuous stream. By contrast, I'm hearing of increasing numbers now in and around the Crater, with the first being reported (headed south and south west) from the broader Ndutu area. I've also confirmed that the movement hasn't been noted north of the Pare Mountains, suggesting the idea that they originated in the Maasai Steppe and headed north from there might well fit. The other very interesting observation comes from Tent with a View (I think that's their website!), who report 1000s appearing just recently headed south down the coast in Saadani NP. So, if you're in Dar, do look out over the next day or two. How this fits into the pattern, I'm not sure! But keep the records coming and we'll find out.

Meanwhile, I've been reading more papers on butterfly movements in Africa!

Friday, 3 February 2012

Butterfly migration update

Thanks to all who've given me information so far! Numbers are definitly falling now around here, but some big waves are still coming through and that big wave of movement must be headed somewhere else... If you've been following you'll notice that new points have been appearing on the map, though more would be great, so if you've been hesitant, please do let me know. You can either add points yourself here, email or SMS me (if you know my number of course) or add a comment to the blog and I'll update things. I'm just as keen on negative data as positve ones if you're in the area - I'm getting hints that there's nothing moving in southern Tarangire, for instance, but only because I've been asking folk there and they've all been silent! Similarly, I think it's negative all over Serengeti, but I'm struggling for people to tell me that despite sending lots of messages!

Vachellia and Senegallia species in massed flower near Longido, Jan 2012
Some things I've been wondering about that might help us piece things together include information on average flight speeds for butterflies of other species - around 14kmh for Monarchs, butteflies that like a little tail wind. And between 10kmh and 6kmh for a range of other species in still air (higher speeds usually by migrant species, but not specifically recorded on migration). When our African Monarchs are on the move they seem to travel at about the same speed as the whites and they use a following breeze too, so let's assume a similar flight speed. Now I first noticed movements in Arusha on Tuesday, but it could have started sooner. Most movement has been between 10am and 5pm, giving 7 hrs of movement time. And most of the butterflies haven't been stopping much to feed. So let's say each individual has been moving for 7hrs on three days, they should have covered nearly 300km in that time. My most easterly records of the movement on the map (did I say to help me fill it in?!) are from Korogwe on Wednesday, when a notiable movement was headed NW - not as many as elsewhere at that time, but I don't know what it was like there on Tuesday or Monday. So those eastern butterflies are around 300km from me, if they followed the direction of movement we've been recording. If they flew each day, they'd be passing here about now. It's tempting to think the lower numbers at the moment represent the end of a continouos movement from Korogwe to here, whilst the peak that was here should no be about 300km further along, takingus beyond Eyasi and into uncharted territoriy. Anyone know folk in Singida or out that way who might tell us what they've seen?

Wednesday, 1 February 2012

Mapping the butterfly eruption

OK, I got rather a lot of information thanks to the previous post and thought we'd cash in on it as fast as possible - the butterflies are moving again over Ilboru right now, not in large numbers yet, but it's still cool. I think I've created a google map that anyone can edit with their location and observations. It's not a polished item, but I've put what I've discovered in for far and it's already interesting. (If anyone tech-savvy can make it neater I'd love to have icons that reflected the direction and volume of movement, rather than just pins...) If we get lots of observations on this it will definitely make a note for some lepidoptera publication and we'll have pushed back the frontiers of science, which would be great!

View Butterfly eruption 2012 in a larger map

So, instructions....

Butterfly migration out now!

African Caper White Belenois aurota
Beleonis creona African Common White
If you're anywhere near me at the moment and it's not dark, get off your seat and look outside. There is a phenomenal butterfly migration happening in the Arusha area at the moment - from my garden in Ilboru I'm counting around 100-150 white butterflies headed west over a 20m wide patch of sky every minute. Truly spectacular! I'd love to know how widespread the migration goes, so if your on safari and getting this on your mobile, let me know what's happening where you are too. I first noticed the movement yesterday and expect it will keep going for a while yet. The butterflies involved all seem to be the African Caper White B. aurota, though there could easily be some African Common White, Belenois creona (subspecies severina) in there as well. Look carefully for a while and there are one or two of the African Migrant Catopsilia florella a much larger and yellow tinged butterfly. The main difference between the two Belenois is that the male in the Caper White has a bar on the forwing and the Common White just as a spot - but it's not always easy to decide if it's a spot or a proper bar as there's lots of individual variation, so I might have got a few pics confused here. Let me know if you're better at these butterflies than me!