I’ve just returned from a fun but fairly hectic trip to the Kalahari. This chance came about because there is a new PhD student starting on the pied babblers but no one was available to train her. So, on a plane I hopped and met up with Amanda Bourne. She’s going to be looking at climate effects on the babblers and be part of the Hot Birds Project. Her work is going to be a mix of: physiology, trying to understand the metabolic costs; behavioural, working out if temperature impacts on social and group cohesive behaviours – trying to see if sociality may act as a buffer to high temperatures; and investigating cumulative impacts of high temperature on groups and individuals. All this is really cool, interesting, and (pardon the pun) hot stuff. She is following on from other hot birds work at the Kuruman River Reserve: van de Ven et al. 2016 found that hornbills can regulate blood flow to their beaks to regulate their temperature without evaporative heat loss; du Plessis et al. 2012 found that increasing temperature caused a decrease in the foraging success of pied babblers, with birds displaying heat dissipation behaviour while foraging. She’ll also be able to build on some recent babbler work by Lizzie Wiley who found that adults provisioned nestlings much less on hot days, resulting in decreased nestling growth (Wiley & Ridley 2016).
 
So why was I there? Well the babblers are a bird with lots of complex behaviours, fairly defined territories and the project has specific protocols to maintain consistent data collection over its 13 year history. The privilege fell to me to basically walk around and look at birds for 10 days solid, life is so hard! But in all seriousness, the study population consists of wild birds who have been habituated to close human presence and without knowing how to act around them it is possible to dehabituate them very quickly and see your PhD data quickly fly away. I was also able to help Amanda figure out potential research questions and experiments that she wouldn’t have been able to think of without seeing how they behave.
 
Before heading off I was anticipating a fairly dull period in the field: its winter, they’re hungry and so they just forage and fly about between the distant patches of low density prey. How wrong I was. This has been a very odd year in the Kalahari, late summer rain in April and a mild winter led to a bumper abundance of food. When food is not a problem the babblers, and all of the other Kalahari animals for that matter, get it on and babies are the result. We arrived to find multiple groups with fledglings, and so the veldt was alive with the begging of babblers – music to my ears. Following these groups of babblers where the scimitar bills taking advantage of babbler sentinels and the ubiquitous drongos. We found groups like Centaurus (pictured below) incubating and even observed some egg eating in a group with females who were competing for reproduction. Whilst other groups were having large aerial battles with their neighbours. Amanda was privileged to observe a dispersal event, the dominant female of Vivaldi was fed up with her light weight male and decided to fly across to join the much heavier male of neighbouring group Noleg, even though at one point she flew back to join her old group for a fight against another group before quickly remembering that she’d left.
 
Whilst looking for groups, and teaching Amanda the babbler whistle (an ululating call to get the birds to fly to you) and group territories, we came across wild groups and individuals who had dispersed from the study population (one may have last been seen in the population in 2004!! – although confirmation is still needed). One of these wild groups was right in the middle of the reserve and feeding a nest, so they’ve been named (Martu- pronounced Mardu – after the aboriginal people of the Western Deserts of Australia) and habituation may start in September when Amanda gets back. 

Amanda’s boyfriend, plant biologist and restoration ecologist extraordinaire, Todd Erickson also came along. He was able to use my camera a lot more than I was, and many of the pictures on the blog post were taken by him. Todd’s botanical leanings allowed me to see the veldt in a new way, paying attention to the small succulents, grasses and flowers that had flourished because of the late rains. The Kalahari was filled with colour, majestic in its flora. This colour had been included in the babbler nests, with many of them decorated with the lovely yellow flowers that littered the landscape. Todd’s insights about how dunes actually hold water better than the slacks, meaning that larger trees and shrubs can grow there, blew my mind and made me look at the landscape in a completely new way. This is why I love science, there are so many disciplines and you can always learn something new that changes your world view.
 
I’ve written mostly about the babblers, and that’s because they are awesome, but there are many other projects at the KRR. There is the over 20 year study of meerkats, who have had a terrible year: prior to the late rains it had been a drought and their groups had been decimated by the combined disasters of no recruitment and TB, but they had started to breed in the winter. The Cape Ground Squirrel Project, started by my friend Jamie Samson, is still going strong and again they have had loads of strange winter pups. And for those of you who want to fly to South Africa, travel for hours to the remote Kalahari and then spend most of your time indoors there are always the molerats to work on. That might sound a bit negative but I like being outside and observing animals behaving in their natural habitat and the idea of spending all day under florescent lights (something you can do in an office) in a building that smells of pee (something you get in public toilets) isn’t something that appeals to me. The other cool birds that are studied at the KRR are the hornbills (mentioned above) and the drongos – who spend their time either stealing food from other animals with their vocal mimicry, catching flying insects with ease using their aerial acrobatics or just pissing off large raptors by bomb diving them.

It was very special to go back to the Kalahari, a place that I have spent a lot of time. Seeing the babblers again, watching them play in shepherd’s trees, feed their fledglings or just have them hop on my feet as I weighed them was very special. I also found out that part of my hippocampus is forever engraved with a map of the reserve: I could still walk straight to ladders hidden behind bushes, find trees that had been used as nests in the past and always point to Whiskers Crossing. Part of me will always be in the Kalahari, and no view will ever be as beautiful as the sun setting over the dunes or a time as peaceful as dawn in the veldt.

This morning I awoke to a science media awash with reporting on a new paper produced from a field site that I spent many years at. The work is a new paper, published in Nature, on meerkats and competitive growth. To name (and link) just a few of the news stories, it was covered by the Guardian, Science, Science Daily and National Geographic – pretty widespread and prestigious, not to mention far reaching, media coverage. I don’t want to go into all the ins and outs of this new bit of research, as exciting as it is, as you can just click on the above links or read the article yourself (link and abstract at the end). But the gist is that in meerkat litters, if your siblings are growing faster than you then you increase your food intake and growth rate to try and match them, this was elucidated using some really great experiments (details of that later). This is really important for cooperatively breeding species like meerkats, where reproductive skew is high with only a few individuals ever reaching dominance. So in order to maximise their chances of competing with their litter mates, meerkat pups up their food intake. Simples!
 
What I want to briefly expand on here is the importance of long-term research in this discovery. The study animals used for this work are wild, they all live out their lives in the Kalahari and are beset by the hardships of competition, constant foraging and threats of predation. However, these meerkats (like the babblers that I worked on) are habituated to human observation. This habituation has huge benefits, it allows close observation of interactions, it allows for identifying individuals, it allows for field experiments to be done (be they playing back specific calls or tactically feeding specific meerkats as they did here!) but in the case of the meerkats (and the babblers) it allows researchers to weigh them multiple times a day. You may ask what does this have to do with long-term research? Well meerkats are naturally very skittish, they’re not very big and lots of things want to eat them. It typically takes between 12-24 months to habituate a group up to a good level, from spending hours sitting at a burrow as still as possible but humming the habituation song all the way to walking with them and weighing them. And to have a study population of between 16-25 groups that is a lot of man hours. To get around all of those groups on a regular enough basis you need a small army of researchers, constantly collecting weights, life-history data and helping out with experiments.

This work is also built upon decades worth of other research on these animals, which is not possible without uninterrupted observation. Slowly but surely this work unravelled the natural history of these animals, opening up interesting research questions, which in turn attract researchers with other interest that open up new avenues of research. Long-term studies thus offer a great avenue to expand our knowledge just simply by persisting in one place over a long time. They also tend to build up a network/family tree of researchers who have either worked or done PhDs or post-docs there, and once they move on they are a valuable link between research institutions. Ironically, even though the meerkats have been shown to not be very incestuous, the meerkat research are less averse to such behaviour!
 
All of these ideas are summed up in a great paper entitled: Individuals and populations: the role of long-term, individual-based studies of animals in ecology and evolutionary biology. Long-term study populations exist in many species across all taxa. The meerkats, red deer, Arabian babblers, blue tits, marmots, big horn sheep and pied babblers are just the ones that come off the top of my head. All of these have contributed massively to our understanding of behavioural ecology, population biology and conservation. So when I see a paper like this new meerkat paper I don’t just see the work of the named authors (shout out to Matt Bell – legend) but also to the tens to hundreds of volunteer researchers who have kept those projects going over the decades of their existence (of which I was once one). I hope that after reading this that you’ll appreciate that too.
  
Huchard et al. (2016) Competitive growth in a cooperative mammal. Nature, doi:10.1038/nature17986
 
In many animal societies where hierarchies govern access to reproduction, the social rank of individuals is related to their age and weight1, 2, 3, 4, 5 and slow-growing animals may lose their place in breeding queues to younger ‘challengers’ that grow faster5, 6. The threat of being displaced might be expected to favour the evolution of competitive growth strategies, where individuals increase their own rate of growth in response to increases in the growth of potential rivals. Although growth rates have been shown to vary in relation to changes in the social environment in several vertebrates including fish2, 3, 7 and mammals8, it is not yet known whether individuals increase their growth rates in response to increases in the growth of particular reproductive rivals. Here we show that, in wild Kalahari meerkats (Suricata suricatta), subordinates of both sexes respond to experimentally induced increases in the growth of same-sex rivals by raising their own growth rate and food intake. In addition, when individuals acquire dominant status, they show a secondary period of accelerated growth whose magnitude increases if the difference between their own weight and that of the heaviest subordinate of the same sex in their group is small. Our results show that individuals adjust their growth to the size of their closest competitor and raise the possibility that similar plastic responses to the risk of competition may occur in other social mammals, including domestic animals and primates.

A cool paper by Bell et al has just come out in Nature Communications (abstract and link below). The study uses a hormonal manipulation to investigate the evolution or reproductive suppression in cooperatively breeding meerkats. Similar work has been done on banded mongooses. The national press picked up this recent paper because it was on meerkats, who in the UK are Russian and compare car insurance prices (this statement isn't meant to detract from the quality of the research). However, the response of the public to this work has been a bit odd, read the comments on the bottom of the dailymail coverage. I think these comments highlight the publics lack of understanding of how science works. A large amount of the comments seems to say that this has been known for ages because it was on Meerkat Manor, and so thought the work pointless. But this work is new and novel, providing an experimental approach to testing the hypothesis of adaptive reproductive suppression. What the tv series reported was based on correlational data and theories, but this work has proved it experimentally. I just hope that these comments say more about dailymail readers than it does about the average persons understanding of science and how it relates to semi-fictional soap-opera-style documentaries.

Bell, Cant, Borgeaud, Thavarajah, Samson & Clutton-Brock (2014) Suppressing subordinate reproduction provides benefits to dominants in cooperative societies of meerkats. Nature Communications.
In many animal societies, a small proportion of dominant females monopolize reproduction by actively suppressing subordinates. Theory assumes that this is because subordinate reproduction depresses the fitness of dominants, yet the effect of subordinate reproduction on dominant behaviour and reproductive success has never been directly assessed. Here, we describe the consequences of experimentally preventing subordinate breeding in 12 groups of wild meerkats (Suricata suricatta) for three breeding attempts, using contraceptive injections. When subordinates are prevented from breeding, dominants are less aggressive towards subordinates and evict them less often, leading to a higher ratio of helpers to dependent pups, and increased provisioning of the dominant’s pups by subordinate females. When subordinate breeding is suppressed, dominants also show improved foraging efficiency, gain more weight during pregnancy and produce heavier pups, which grow faster. These results confirm the benefits of suppression to dominants, and help explain the evolution of singular breeding in vertebrate societies.
http://www.nature.com/ncomms/2014/140722/ncomms5499/full/ncomms5499.html

and a link to that banded mongoose paper:
http://www.bandedmongoose.org/wp-content/uploads/Cant-et-al-2014-PNAS.pdf

I recently attended the annual Meerkat-Mongoose Meeting, organised by LARG, at the University of Cambridge. This small scale conference has been going for a number of years and allows researchers working on meerkats, banded mongoose, and other species at the Kuruman River Reserve and other random study species, to come together and talk about proposed future work and unpublished research. The atmosphere is great, very like a student conference, and allows a fairly informal environment for critical feedback. 
At this meeting a very different topic came up: a new educational book inspired by the work of the Banded Mongoose Project to inspire and educate children in Uganda and the UK. The project has brought out a book called 'Billy the Banded Mongoose', which you can buy or use (if you're a teacher) as an educational tool and the proceeds go to helping education in Uganda. Here is the link:
http://billythebandedmongoose.co.uk/

And here are some other links related to the Meerkat-Mongoose Meeting:
Kalahari Meerkat Project
Babbler Research
IEU at Zurich University

I know this ‘coverage’ is a bit late but I was on a remote Scottish Island when this paper came out and as Tom is the first of my friends to get a paper in Science I obviously had to write about it. And as you will now know, I know the authors and so my slant on this paper will probably be biased in a positive way.

So the paper is:

Flower et al (2014) Deception by flexible alarm mimicry in an African Bird. 344: 513-516

Firstly you’ll need a bit of background on fork-tailed drongos (Dicrurus adsimilis), hereafter drongos. They are extremely agile birds that live in Southern Africa and are very adept at hawking small flying insects. In addition to their aerobatics they are vocal mimics that can copy the calls of other species, and they use these calls to make false alarm calls (i.e. when there are no real predators) to scare individuals from other species (host species) when they have food, then they fly down and steal the food item. Drongos primarily spend time with sociable weavers (Philetairus socius), pied babblers (Turdoides bicolor) and meerkats (Suricata suricatta). Previous work has investigated some of these associations, and I have put the papers at the end.

The problem with using these false alarm calls to gain food from other species, usually food that drongos are unable to gain themselves, is that if you are deceptive too often then your hosts will stop responding. However, these host species don’t just have their food stolen by drongos, they actually use drongos as part of their vigilance system as drongos will alarm at actual predators. Thus there is an interesting ‘mutualism’ that exists within this system. This investigation sought to understand how drongos maximize their gain from these repeated interactions.

Natural observations of this wild population showed that drongos exclusively use mimetic alarm calls in 42% of false alarms and a combination of mimetic and drongo specific calls in a further 27%. To investigate these patterns the researchers carried out a playback experiment using four drongo generated call types:  1) a control territorial call 2) drongo-specific alarm 3) mimic of glossy starling (Lamprotornis nitens) alarm and 4) mimic of pied babbler alarm. The experiment was carried out on groups of habituated pied babblers, a host species for the drongos. Pied babblers were slower to return to foraging after mimetic alarms than drongo specific ones, thus showing that mimetic alarm calls produce a stronger response. They then carried out a second experiment where they played back three calls in one of four treatments: 1) All drongo-specific alarms 2) All mimetic starling alarms 3) two drongo followed by a starling and 4) two starling followed by a drongo alarm. They found that pied babblers habituated to treatments of all one type but not to the treatments that varied. Showing that varying the calls you use has benefits for the drongo. These experimental results fit with the natural data that showed in instances of repeated attempts at theft on the same individual that drongos changed the false alarm call that they used on 74% of occasions. Drongos were more likely to change if their previous attempt had failed.

This paper shows that drongos avoid host species habituating to false alarm calls by varying the mimetic false alarms that they use and thus avoiding frequency dependent constraints.

This paper has a great blend of natural observation and carefully designed experiments. The results speak for themselves and tell an interesting story of how birds in the wild adjust to problems that are familiar to many people. It shows the value of working at a research site with multiple habituated species that associate and interact in interesting ways, and thus the value of long-term research stations.

Some of the media coverage seems to have sensationalized this work, going much further with their assertions than the authors did. Some have even suggested that these birds have ‘theory of mind’. Sciencemag noted that Tom (Dr Flower) is doing some current work to further investigate drongos tactics and learning, work that I assisted with in the Kalahari. From my observations while performing these experiments the drongos seemed to use simple rules and were not as clever as we had hoped. However, that does not detract from the brilliance of their behaviour: many complex behaviours and structures are made using simple rules, e.g. spider’s webs and wasp nests. Even some seemingly complex human behaviours are governed by simple rules. The amazing adaptability of evolution is shown by such seemingly complex behaviours. In fact the authors use examples such as the changing of cell surface proteins by influenza as an analogue to drongo behaviour, and I’m pretty sure that virus’s don’t have theory of mind!

Here are some links to other media coverage:

http://news.sciencemag.org/biology/2014/05/african-bird-cries-wolf-steal-food?rss=1

http://whyfiles.org/2014/deceptive-bird-lies-to-steal-food/

http://www.nbcnews.com/science/weird-science/african-bird-uses-sound-effects-bamboozle-other-species-n94256

More drongo papers:

Flower et al (2013) The ecological economics of kleptoparasitism: pay-offs from self-foraging versus kleptoparasitism. Journal of Animal Ecology 82:245-255

Flower & Gribble (2012) Kleptoparasitism by attacks versus alarm calls in fork-tailed drongos. Animal Behaviour 83:403-410

Ridley & Child (2009) Specific targeting of host individuals by a kleptoparasitic bird. Behavioral Ecology & Sociobiology 63: 1119-1126.