​As a biologist and someone who spent many years wandering around in remote locations looking at animals it is often hard to explain how I view the world. Many people seem to walk through the streets of their towns and cities blissfully unaware of the flora and fauna that surround they. All they see are streets, cars, buildings, traffic lights or bus stops. For me it’s the birds that I notice most, be it a male rock pigeon puffing his chest up and strutting in vain in front of a female who just wants to be left in peace to forage or a robin with a beak full of food stood on a suburban fence waiting to fly to its nest of hungry chicks. London, with its multitude of parks and open spaces, is a haven for wildlife. I still text my fiancé every time I see an urban fox, it brings a shiver of school boyish excitement. But I often see people wander blindly past interesting natural history that is right in front of them: I remember watching a pair of blackbirds chasing a jay away from an area that was presumably their nest site, or a squirrel that was barking in alarm at a sparrowhawk sat in a tree above a oblivious man. Maybe it is my years of working on birds that alerts me to these things but I really believe that if everyone noticed them that it has the capacity to make a crappy walk home from work amazing, lifting your spirits. Even noticing the melodic tunes of a male blackbird or watching the swallows swoop overhead on a summers evening can bring a natural majesty to any suburb. These scenes, and many more, playout every day in our cities. To add to this there is the majesty of the blossoming of the trees and their fruiting, the bluebells and snowdrops and daffodils that brighten our streets.

The podcast is an episode of 99 Percent Invisible. This podcast is about design but somehow and for some reason its episode "Unseen City: Wonders of the Urban Wilderness" chimes perfectly with how I see the urban landscape as I walk about London. This may just be me, I may be odd, but I thought I'd share it with people who either don't see the world this way or who want to show other people what it's like to be them.
 
Just one final story of urban nature. About a month after we moved into our flat in North London we saw a sparrowhawk catch and kill a juvenile magpie in our garden, meters from the glass. The incident took over half an hour, with alarm calls and cackling from the traumatised magpie family as the sparrowhawk mantled its prey.

A recent bit of research has just come out that shows that bird populations in Europe and the US are being impacted by our changing climate. This work was even picked up by the BBC. By using a combination of great long-term datasets and some nifty models that they created, the researchers were able to predict current population distributions. This is not just well done research but also a testament to the importance of long-term population monitoring, something that isn’t sexy and since the financial crisis hasn’t received as much funding as other more applied areas of science (sorry this is a pet peeve of mine and I’ll get off this tall equid that I now find myself on). What the research has shown is that species that are predicted to benefit from climate change are benefiting, and those that are predicted to suffer are suffering. Both positive and negative effects can occur within a single species, as they may be declining in southern regions but thriving in northern areas.
 
The trends shown by this new research are large scale continental patterns but what factors may be driving these at a finer, individual level scale? Work done by researchers like Susie Cunningham, Rowman Martin and my pied babbler colleague Lizzie Willey is shedding light on this. Work by these researchers, and others, has shown that when temperature increases it can have dramatic effects on the reproduction of birds, their ability to forage and the viability of their social groups. Nestling fiscal shrikes grow slower when temperatures increase over a threshold level: this increases the risk of nest failure and results in smaller fledglings who are likely to incur a fitness cost. Similarly, on warmer days pied babblers are less efficient at foraging and put on less weight while foraging. If multiple extremely hot days occur in a row this could have a dramatic impact on an individual’s weight, and if they are caring for young then temperature will impact adults, offspring or both. Anecdotal evidence, hopefully soon to be verified statistically, of pied babbler groups is that in the hottest years more groups fail to raise any offspring and become extinct, presumably from the direct effects mentioned above. All of these small individual level mechanisms may help to understand the drivers behind higher level continent wide patters.
 
But climate change doesn’t just act on its own, it occurs in conjunction with direct habitat change caused by humans. Pied crows in South Africa have changed the areas in which they live based on a change in climate but it is facilitated by power lines. These birds need to nest in trees and the existence of power lines has allowed them to colonise treeless areas and take advantage of them.
 
But what does all of this mean? By understanding the lower level effects it may be possible to design or implement habitat measures that can mitigate some of these effects. This may be farfetched, as these are large scale problems. For example when putting up nest boxes for endangered species it is important to ensure that they are not going ‘cook’ the nestlings inside, it’s worth spending that extra time researching this before spending large sums of money on a conservation effort that is doomed to fail. Small and simple considerations like that may have an impact.
 
For more information on this type of research you can visit the Hot Birds Research Project.
 
Some papers that look at the direct effects:

Cunningham et al. (2013) Temperatures in Excess of Critical Thresholds Threaten Nestling Growth and Survival in A Rapidly-Warming Arid Savanna: A Study of Common Fiscals. PLoS ONE
Frequency, duration, and intensity of hot-weather events are all predicted to increase with climate warming. Despite this, mechanisms by which temperature increases affect individual fitness and drive population-level changes are poorly understood. We investigated the link between daily maximum air temperature (tmax) and breeding success of Kalahari common fiscals (Lanius collaris) in terms of the daily effect on nestling body-mass gain, and the cumulative effect on size and age of fledglings. High tmax reduced mass gain of younger, but not older nestlings and average nestling-period tmax did not affect fledgling size. Instead, the frequency with which tmax exceeded critical thresholds (tcrits) significantly reduced fledging body mass (tcrit = 33°C) and tarsus length (tcrit = 37°C), as well as delaying fledging (tcrit = 35°C). Nest failure risk was 4.2% per day therefore delays reduced fledging probability. Smaller size at fledging often correlates with reduced lifetime fitness and might also underlie documented adult body-size reductions in desert birds in relation to climate warming. Temperature thresholds above which organisms incur fitness costs are probably common, as physiological responses to temperature are non-linear. Understanding the shape of the relationship between temperature and fitness has implications for our ability to predict species’ responses to climate change.

Cunningham et al. (2013) Identifying Biologically Meaningful Hot-Weather Events Using Threshold Temperatures That Affect Life-History. PLoS ONE
Increases in the frequency, duration and intensity of heat waves are frequently evoked in climate change predictions. However, there is no universal definition of a heat wave. Recent, intense hot weather events have caused mass mortalities of birds, bats and even humans, making the definition and prediction of heat wave events that have the potential to impact populations of different species an urgent priority. One possible technique for defining biologically meaningful heat waves is to use threshold temperatures (Tthresh) above which known fitness costs are incurred by species of interest. We set out to test the utility of this technique using Tthresh values that, when exceeded, affect aspects of the fitness of two focal southern African bird species: the southern pied babbler Turdiodes bicolor (Tthresh = 35.5°C) and the common fiscal Lanius collaris (Tthresh = 33°C). We used these Tthresh values to analyse trends in the frequency, duration and intensity of heat waves of magnitude relevant to the focal species, as well as the annual number of hot days (maximum air temperature > Tthresh), in north-western South Africa between 1961 and 2010. Using this technique, we were able to show that, while all heat wave indices increased during the study period, most rapid increases for both species were in the annual number of hot days and in the maximum intensity (and therefore intensity variance) of biologically meaningful heat waves. Importantly, we also showed that warming trends were not uniform across the study area and that geographical patterns in warming allowed both areas of high risk and potential climate refugia to be identified. We discuss the implications of the trends we found for our focal species, and the utility of the Tthresh technique as a conservation tool.

Cunninham et al. (2016) Electric crows: powerlines, climate change and the emergence of a native invader. Diversity and Distribution
Aim
Climate change and other anthropogenic global change drivers act in complex, mutually exacerbating ways to alter the abundance and distribution of species. In South Africa, pied crowsCorvus albus have increased in numbers and range in recent decades. Popular opinion links these changes to urbanisation and infrastructure development, but there has been no empirical test of this idea. We aimed to clarify the drivers of pied crow population changes in South Africa.
Location
South Africa.
Methods
We used publicly available long-term datasets, the Southern African Bird Atlas Project and University of Delaware Gridded Climate Database, and spatial data from government bodies, to assess relationships between pied crow population and range changes, land use, infrastructure, urbanisation and climate change.
Results
Pied crow numbers have increased significantly in the past three decades, but rate of increase varied geographically, with crows declining in the northeast and increasing in the south-west of South Africa. Pied crow population changes were strongly correlated with climate change. Crows have benefited most from climate warming in the shrubland biomes of south-western South Africa. Pied crows are tree nesters, and within these shrublands, there is a strong positive relationship between the rate of population increase and the density of powerline infrastructure, which may facilitate pied crows’ increase by providing nesting sites.
Main conclusions
Pied crow numbers have increased in response to climate warming, with their spread facilitated by electrical infrastructure in south-western South Africa, providing a clear example of compound influence of multiple global change drivers promoting a significant change in species range and reporting rate. Pied crows are generalist predators and there is popular concern about their ecological impact in areas where increases have occurred. We highlight the importance of understanding the ecosystem-level implications of increased numbers of pied crows in South Africa's shrubland biomes.

Du Plessis et al. (2012) The costs of keeping cool in a warming world: implications of high temperatures for foraging, thermoregulation and body condition of an arid-zone bird. Global Change Biology
Recent mass mortalities of bats, birds and even humans highlight the substantial threats that rising global temperatures pose for endotherms. Although less dramatic, sublethal fitness costs of high temperatures may be considerable and result in changing population demographics. Endothermic animals exposed to high environmental temperatures can adjust their behaviour (e.g. reducing activity) or physiology (e.g. elevating rates of evaporative water loss) to maintain body temperatures within tolerable limits. The fitness consequences of these adjustments, in terms of the ability to balance water and energy budgets and therefore maintain body condition, are poorly known. We investigated the effects of daily maximum temperature on foraging and thermoregulatory behaviour as well as maintenance of body condition in a wild, habituated population of Southern Pied Babblers Turdoides bicolor. These birds inhabit a hot, arid area of southern Africa where they commonly experience environmental temperatures exceeding optimal body temperatures. Repeated measurements of individual behaviour and body mass were taken across days varying in maximum air temperature. Contrary to expectations, foraging effort was unaffected by daily maximum temperature. Foraging efficiency, however, was lower on hotter days and this was reflected in a drop in body mass on hotter days. When maximum air temperatures exceeded 35.5 °C, individuals no longer gained sufficient weight to counter typical overnight weight loss. This reduction in foraging efficiency is likely driven, in part, by a trade-off with the need to engage in heat-dissipation behaviours. When we controlled for temperature, individuals that actively dissipated heat while continuing to forage experienced a dramatic decrease in their foraging efficiency. This study demonstrates the value of investigations of temperature-dependent behaviour in the context of impacts on body condition, and suggests that increasingly high temperatures will have negative implications for the fitness of these arid-zone birds.

Recently we’ve all been told that this is the Anthropocene, an age where human impact will be detectable in the ages to come. Much of what this idea encapsulates and is written about in the media is to do with habitat destruction, species loss and climate change but in addition to these and really because of these we are also impacting on the evolution of the species that live with us. Evolution by natural selection leads to the individuals of a species best adapted to that specific environment to survive for longer and reproduce more than those less well adapted. The big thing here is that we, humans, are changing that environment and therefore the direction of selection.
 
Like Darwin, I’ll start with an obvious example of how we have affected the evolution of species: domestication.  Cows, sheep, pigs, chickens et al. resemble their wild ancestors but in many ways are very different. These animals now produce more meat, lactate more and are a lot more docile than their progenitors. This isn’t just something that we’ve done to animals but also plant: modern wheat looks very different from the grasses that hybridised to produce its ancestor and maize is hugely different from teosinte. Since the advent of agriculture, humans have selectively bred the plants and animals with the characteristics they desired the most and this has even happened with pets, leading to some ridiculous breeds.
 
All of the examples above are ways that humans have influenced evolution either intentionally or in ways that we’ve directly benefited from. Another common example that is often in the press, but which we don’t benefit from, is antibiotic resistance. Through our use of antibiotics to prevent and cure infections and diseases we have created a huge selection pressure on pathogens, specifically bacteria, to develop resistance to these drugs. This has resulted in antibiotic resistance. We’ve changed the environment and created a massive advantage to those individuals whose mutations convey resistance. This is evolution on super drive, as bacteria reproduce rapidly, one bacteria could produce a billion descendants in 10 hours (if conditions are right), and can transfer genes between species, further accelerating the process.
 
Human activity is directly impacting on the evolutionary trajectories of species that are much bigger than bacteria. Humans are a super predator, able to take large numbers of a species at a fast rate and not switching when their numbers fall. This form of predation creates a huge selective pressure on the prey species to change. Atlantic cod, the species that Brits prefer as part of our fish’n’chips used to be over 2m long. By removing large fish, through commercial fishing, we’ve created an environment were being smaller and reaching sexual maturity earlier is optimal. This human induced change in the environment has led to cod evolving to be smaller and that males are becoming sexually mature earlier. But this doesn’t just mean that our fish’n’chips will decrease in size (it’s not a Tory plot) but it changes the whole ecosystem as cod’s place in the food chain will change, now becoming prey when it once was a predator.
 
Predation doesn’t just impact the evolution of the species we exploit commercially but also those that we hunt for fun. This is something that I’ve seen first-hand while working in South Africa. We shot antelope on our ‘farm’ solely for food, and as such just took the first ones we found (if they weren’t pregnant). As such, our male springbok hand lovely big, symmetrical horns, because the predation pressure was in effect random. Our neighbours, who often had trophy hunters pay to come onto their property and pay to shoot males with big horns had male springbok with smaller, less impressive horns (even when of comparable size). By selectively shooting males with large horns humans had produced a change in the predation regime that made having big horns very costly and so selected for males with smaller horns. This isn’t just anecdote; trophy hunting has been shown to have reduced the size of bighorn sheep’s horns by about 25%. This isn’t just an impact on the physical appearance of males but also of the way that mate selection takes place. Prof David Coltman, author of this research, explains: "The crux here is that the horns develop to the length where they can be legally harvested several years before they achieve social dominance. So in effect they're being harvested from the population before they can reproduce and pass their genes on."
 
Urban environments are not devoid of nature. Many bird species are common in towns and cities throughout the world. However, living in a habitat that differs so much from the one that these species have evolved in has led to many behavioural and physiological changes. One of the obvious ones is that bird song in urban areas differs to the song of the same species in more ‘natural’ habitats. Birds sing at different times, even at night, to avoid noise interference. The actual acoustic structure of bird song has also changed in urban environments, and this is a crucial aspect of not just mate selection but territorial behaviour in many of these species. The optimal behaviour of a species in an urban area can be different to that of individuals of the same species in wilder areas, urban birds may not migrate like their ‘wilder’ brethren and this is an anthropogenically driven adaptation. An finally, urban areas may act like islands because they are invaded by a small number of individuals of a species creating founder effects but also because urban individuals do not regularly breed with their wild neighbours, effectively isolating themselves off. This has happened in the European blackbird and resulted in reduced genetic diversity of urban populations but also resulted in physical differences between urban and rural birds.
 
Adding to all of this is the increased movement that human activity has allowed certain species. This has meant that species can move between continents like never before, creating novel ecosystem assemblages and interactions. The presence of alien species, which are often well adapted to human disturbed environments, offers new unexplored avenues for evolution to try out. This is a lot more speculative than the previous paragraphs, but new mutualisms, host-parasite relationships and even hybrids may be created because humans have allowed animals and plants to move further and faster than ever before.
 
This is both fascinating and frightening at the same time. But without studying these impacts it is not possible to gauge how we can reduce/stop them, or even enter a debate into whether we need to intervene at all? Are we not just another part of the environment?

The story of the dreaded neonicotinoids and there proposed deadly effect on Europes bees has been reported widely in the press over the last year or so. The story has gotten ugly as there have been claims and counter claims of dodgy science on both sides of the debate. But pesticides in general may be having an effect far wider than just on bees.

I'll state first up that I am not anti-pesticides. Without them modern agriculture couldn't exist, we'd have much higher food prices and no doubt people's diets would be worse for their absence. But they will have an environmental impact that is far less easy to detect than any 'endocrine disrupting' effect that groups like the Pesticide Action Network rave and shout about.  What is needed is an informed discussion about the risks that these chemicals have, not only to bees and humans but to wildlife further afield. Using long-term demographics and detailed studies of birds and other animals we can hope to determine these impacts. Unfortunately, many of the staunch anti-pesticide campaigners are also very anti GM: a technology that has the potential to actually reduce our impact on the environment and increase sustainability. 

Pesticides kill insects, that is what they are designed to do. Almost all non-ratpor or seabird species (I can't think of an easier way of writing this!), whether they as adults each insects or seeds, feed their chicks insects. As a food source, as many an alternative website will state, insects are very high in protein - the ideal thing for a growing chick! With the majority of the UK being either urban or under agriculture that leaves environments that are either a) probably fairly low in insects or b) get sprayed with pesticides to reduce the number of insects.  Many species of native British birds are on the decline, house sparrows declined by 71% between 1977 and 2008, common cuckoo number are hugely down, there is obviously a problem but is it a singular one or is each species decline due to their own specific factors? However unique the behaviour and ecology of each declining species, It seems that more and more studies and ornithologists are at least in part blaming pesticides for the reduction in bird numbers. If birds are unable to feed their offspring then recruiting individuals into the population is reduced, and as birds age or die from disease or predation then the population will decline. And if the adults themselves rely on insects for their own food then surviving or getting up to reproductive weight becomes even harder.


It is very difficult to show causation in situations like this, as all that most researchers have is historical records of bird populations and pesticide use. To complicate things further pesticides are not the only thing that can lead to a reduction in insect abundance. Changing land use practices, such as cutting down hedgerows or increasing stocking density are also likely to have impacts on insect abundance. Controlled trials where specific areas are allowed to use pesticides and others are not would be great, but they are expensive and, for an issue like this, long-term. And with our governments current track record for environmental experiments (i.e. the badger cull) few would likely trust the results.


However, the decline of British birds cannot be put solely at the feet of pesticides. Many of our birds have long and complex migrations which we are only now starting to understand. Changes in land use, hunting or a number of other things may be impacting them at various stages along their migrations. For example, in Malta every year thousands of migrating birds are shot - which I find repellent. The decline in insect numbers in the UK may also be due to climate change, insect populations are likely to decline as flowering times and insect emergence times become increasingly out of step.  

So conclusions? I don't have any. I'm just hoping that this issue gets wider attention and enters the debate into both the use of pesticides and the potential benefits of GM.

Just a collection of random papers, theme issues and a blog that I thought looked pretty cool and that some people might find interesting.

First up, a paper about sexual conflict in a hemaphroditic species, plus it involves love darts! Snails have a really interesting mating system and this paper looks into how the costly behaviour of having love darts leads to conflict, sexual arms race and diversification of morphologies.

Kiruma & Chiba (2015) The direct cost of traumatic secretion transfer in hermaphroditic land snails: individuals stabbed with a love dart decrease lifetime fecundity. Proc R Soc B
http://rspb.royalsocietypublishing.org/content/282/1804/20143063

Next up, a themed issue on the biological impacts of artificial light, put together by Gaston, Visser and Holker. Its in Philosophical Transactions and my favourite paper in it is by Dominoni & Partecke called 
"Does light pollution alter daylength? A test using light loggers on free-rannging European blackbirds (Turdus merula)"
http://rstb.royalsocietypublishing.org/content/370/1667.toc

A paper about duetting in wrens. Using playbacks the authors show that females preferentially sing duets with mates to ward off intruders over singing overlapping songs with the 'intruding' female - which they do in the absence of their mate singing.


Templeton et al. (2015) Female happy wrens select songs to cooperate with their mates rather than confront intruders. Proc R Soc B
http://rsbl.royalsocietypublishing.org/content/9/1/20120863


Vocal duetting occurs in many taxa, but its function remains much-debated. Like species in which only one sex sings, duetting birds can use their song repertoires to signal aggression by singing song types that match those of territorial intruders. However, when pairs do not share specific combinations of songs (duet codes), individuals must choose to signal aggression by matching the same-sex rival, or commitment by replying appropriately to their mate. Here, we examined the song types used by female happy wrens (Pheugopedius felix) forced to make this decision in a playback experiment. We temporarily removed the male from the territory and then played songs from two loudspeakers to simulate an intruding female and the removed mate's response, using song types that the pair possessed but did not naturally combine into duets. Females were aggressive towards the female playback speaker, approaching it and overlapping the female playback songs, but nevertheless replied appropriately to their mate's songs instead of type matching the intruding female. This study indicates that females use song overlapping to signal aggression but use their vocal repertoires to create pair-specific duet codes with their mates, suggesting that duetting functions primarily to demonstrate pair commitment.



Lastly, a nice blog about sex ratios in bumble bees. Eusocial hymenoptera are fascinating, they have enthralled scientist for generations. Because of the asymmetric relatedness caused by haplodiploidy the conflicts and cooperation within these societies provide so many avenues for investigation and manipulation.


A little snippet from the blog: "Analysing my data I realised there were two types of colonies: those that quickly started to produce sexual individuals, and others that took much longer. The former invested much more in male production, whereas the latter mainly produced new queens. Hence, it appeared colonies adopted different strategies, and I hypothesised that both strategies could be equally successful, provided a population contains both."


https://blogs.royalsociety.org/publishing/sex-ratios-in-bumblebees-and-an-influential-experience/?utm_source=social_media&utm_medium=hootsuite&utm_campaign=standard--

This is not so much science as a bit of fun. This morning in the Daily Mail, I read it because it's part of my job not out of choice, was an article about choosing the national bird of Britain. This is apparently the brain child of David Lindo, the Urban Birder. The Mail makes many references to the majestic birds that other nations have as their symbol, the bald eagle of the US and Zambia's African fish eagle. These sound impressive birds, but national birds aren't always great: South Africa has the blue crane, it's a nice enough bird to see when your driving through the Overberg but it's hardly imperious. But I digress.

Here is Liindo's top 10 list (in a random order decided by the Mail):

1. Mute Swan Cygnus olor - pretty, but I've seen them attack rowers and they're very scary.
2. Red Kite Milvus milvus - having grown up in Thame, Oxfordshire, these birds fill me with joy. Hearing their cry on a summers day and watching them swoop over the garden or ride a thermal makes me think of home. A strong contender from me.
3. Hen harrier Circus cyaneus - lovely bird, but I've never seen one. I'd personally swap them for peregrines in this list, but that's because they're one of my favourite birds.
4. Puffin Fratercula sp. - they're great, and watching them fly is awesome but for some reason to me they feel Scandinavian, no idea why!
5. Barn owl Tyto alba - eerily majestic, but as we had a resident in our 'gym' in the Kalahari they will always remind me of Africa not Britain.
6. Wren Troglodytidae sp. - cheerful and cheeky, always fun to watch, a bit to much of an LBJ for a national bird (LBJ = little brown jobbie)
7. Kingfisher Alcedo atthis - nothing quite like the flash of blue on a river bank, but they're the symbol of cheep Indian beer at curry houses!
8. Robin Erithacus rubecula - boom, my vote! Cheeky little robin in the garden or the park, singing his heart out and they're pretty tenacious too.
9. Blackbird Turdus merula - I love black birds, seeing them whizz across suburbia calling as they swoop into a bush - reminds me of home.
10. Blue tit Parus caeruleus - very pretty, but perhaps a bit too pretty for us Brits. Lots of good research has been done on them though!


But there is one bird that isn't on the list and you could argue, given it's cultural importance to the UK - it's in the first song in the English language* - it should be. The cuckoo Cucculus canorus. Bringing me onto the awesome book that I've just bought written by Nick Davies about cuckoos: Cuckoo - cheating by nature. So excited to read it!!

*
Sumer is icumen in,
Lhude sing cuccu,
Groweth sed, and bloweth med,
And springeth the wode nu,
Sing cuccu!

This little post was inspired by reading a small piece in the paper, pretty sure it was the Daily Mail, with the headline "Why robins are losing their chirp". The story was about work done by Davide Dominoni, Glasgow University, on the effects of artificial light on birds. This research, along with other work, suggests that light in our urban environments is having a noticeable impact on the behaviour and biology of birds. The birds tend sing for more hours of the day, which will have knock on effects on the other behaviours they do, how much time they spend foraging, and so what condition they're in - all of which effect how well they can breed. Work on variation in natural light, from the different phases of the moon, by Jenny York, has shown a "natural" basis for these behavioural changes.

Work by Bart Kempenaers et al. at the Max Planck Institute in Germany has shown that street lights have a big effect on breeding behaviour. Looking at four bird species, egg laying date was earlier in areas with street lights and males who had territories with street lights were more successful in gaining extra-pair mates than their lamp-less neighbours.

Human induced changes have wide-ranging impacts on wildlife, not just through habitat destruction, but through creating habitats that are colonized by animal and plant species. I've blogged previously about how bird songs have changed since species have moved into urban environments. Looking at the behavioural ecology of species that inhabit human made habitats is an area that has only just begun to be explored. It's an area that I find fascinating and am looking forward to reading more about. It opens up a field of research that can straddle three disciplines: behavioural ecology, conservation and urban planning. If we can understand the impact we're having, on displaying, mating patterns, parental provisioning survival and habitat use, then we can plan urban areas to be friendlier to wildlife and do so while gaining a better understanding of the evolutionary process.


Bit of a rambling blog, but I've not written for a while and so felt that I should at least put something up!

One of my friends (Dom Cram) has just had a paper come out in Functional Ecology. It's a really well designed experimental study looking at the effects of dominance and effort on oxidative stress in white-browed sparrow-weavers. His research found that dominant females, who work the hardest to provision young during the breeding season, suffered a large decline in antioxidant protection over the course of the breeding season. Antioxidants are the compounds that health professionals keep going gaga over in various 'super-foods', as they help to reduce free radicals which build up due to the cells natural processes and can damage DNA and thus potentially make individuals vulnerable to ageing and lots of other nasty things. So the study hints that individuals that work hard could be at risk of increased ageing and a variety of other future problems. The abstract and link are pasted at the end of the blog.

Dom has rightly received a fair amount of media attention for this piece of work, and rightly so. This is important, as the public need to know what their taxes are funding and how this work fits into our broader understanding of the world. He was even interviewed on BBC radio:

https://soundcloud.com/dom-cram/dom-bbc-radio-interview-sept2014

This coverage though has been very varied, even within the ams newspaper. The Telegraph, link pasted below, covered it well but for some unknown reason decided to lead with a picture of elephant seals.... even though the work was done on a small desert dwelling bird. They also lead with "Alpha males..", even though the abstract clearly states that males showed a decline but it wasn't related to rank, the main result was for females. Well it was a good attempt. http://www.telegraph.co.uk/earth/earthnews/11070219/Alpha-males-and-females-at-risk-of-ill-health-and-premature-ageing.html

Above is the reporting from the Times, and this again is pretty good, even has the correct species pictured (and a lovely comic). But if you read the scanned image below you'll see that some one else at the same news paper decided not only to get the species wrong but to link it massively to humans, a gross overstatement, but then also to Bertrand Russell, Francois Hollande and John Maynard Keynes. This is a prime example of awful reporting and exaggeration from what is a well respected newspaper, this is what lay people read and where the get their information. We need better reporting by people who actually understand science, so that the public is better educated and so able to help the government make better science and environmental policy decisions.

Here is the abstract:
Cram et al (2014) Oxidative status and social dominance in a wild cooperative breeder. Functional Ecology, DOI: 10.1111/1365-2435.12317http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.12317/abstract

1. Oxidative stress has been proposed as a key mediator of life-history trade-offs, yet the social factors that affect patterns of oxidative status amongst individuals in animal societies remain virtually unexplored.
2. This is important, as rank-related differences in reproductive effort in many social species have the potential to generate, or indeed arise from, differences in oxidative status across dominance classes.
3. Here, we examine rank-related variation in oxidative status before and after a lengthy breeding season in a wild cooperatively breeding bird with high reproductive skew, in the semi-arid zone of Southern Africa; the white-browed sparrow weaver (Plocepasser mahali).
4. Our findings reveal that prior to breeding, neither sex showed rank-related differences in markers of oxidative damage or antioxidant protection, suggesting that dominants' reproductive monopolies do not arise from superior pre-breeding oxidative status.
5. After breeding, however, females (who provision young at higher rates than males) suffered elevated oxidative damage, and dominant females (the only birds to lay and incubate eggs, and the primary nestling provisioners) experienced differential declines in antioxidant protection.
6. While males also showed reduced antioxidant capacity after breeding, this decline was not dependent on rank and not associated with elevated oxidative damage.
7. Our findings suggest that divisions of labour in animal societies can leave the hardest-working classes differentially exposed to oxidative stress, raising the possibility of hitherto unexplored impacts on health and ageing in social species.

http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.12317/abstract

So after finishing my PhD I went back the kalahari to help Tom Flower out with some cool work investigating deception tactics and learning in fork-tailed drongos. While I was there I also had a chance to help his honours student, Bruce, out with his research investigating the relationship between drongos and sociable weavers. The kalahari is full of cool inter-species interactions (I'll put a couple of papers below). Bruce's work has just been published in Proceedings of the Royal Society, I have put the abstract and a link to the paper below. The work was really fun to do and highlights how conflict and cooperation have to coexist in both and ecological and evolutionary setting, and that this can lead to cool things evolving.

Baigrie, Thompson & Flower (2014) Interspecific signalling between mutualists: food-thieving drongos use a cooperative sentinel call to manipulate foraging partners. Proc R Soc, 281:20141232
Interspecific communication is common in nature, particularly between mutualists. However, whether signals evolved for communication with other species, or are in fact conspecific signals eavesdropped upon by partners, is often unclear. Fork-tailed drongos (Dicrurus adsimilis) associate with mixed-species groups and often produce true alarms at predators, whereupon associating species flee to cover, but also false alarms to steal associating species' food (kleptoparasitism). Despite such deception, associating species respond to drongo non-alarm calls by increasing their foraging and decreasing vigilance. Yet, whether these calls represent interspecific sentinel signals remains unknown. We show that drongos produced a specific sentinel call when foraging with a common associate, the sociable weaver (Philetairus socius), but not when alone. Weavers increased their foraging and decreased vigilance when naturally associating with drongos, and in response to sentinel call playback. Further, drongos sentinel-called more often when weavers were moving, and weavers approached sentinel calls, suggesting a recruitment function. Finally, drongos sentinel-called when weavers fled following false alarms, thereby reducing disruption to weaver foraging time. Results therefore provide evidence of an ‘all clear’ signal that mitigates the cost of inaccurate communication. Our results suggest that drongos enhance exploitation of a foraging mutualist through coevolution of interspecific sentinel signals.
http://rspb.royalsocietypublishing.org/content/281/1791/20141232.abstract

Other cool interspecies interactions:

Pied babblers and scimitarbills:
Ridley, Wiley & Thompson (2014) The ecological benefits of interceptive eavesdropping. Functional Ecology, 28: 197-205

Drongos and pied babblers:Flower (2011) Fork-tailed drongos use deceptive mimicked alarm calls to steal food. Proc R Soc, 278:1548-1555

This is a very brief post to draw people's attention to some things that other people have done. One is an article that a former field assistant at the Babbler Project has written and the other is from PhD comics.

Firstly, Robbie Hopper, who was a PhD field assistant for James Westrip, has written an article about the Babbler Project and the research that has been done on those amazing birds (I am very biased as I spent four years working on them). So here is the link: http://ecopostblog.wordpress.com/2014/06/22/dabblings-with-babblers/

Secondly, PhD comics, the website that probably millions of graduate students look up on a regular basis to provide accurate commentary on their lives, has done a cool cartoon short about Miya Warrington's PhD thesis. This is awesome for two reasons: firstly, her thesis was really interesting and the science is sound; secondly, I sat next to Miya for two months when I visited Macqaurie University while I was writing up my PhD. She's a very enthusiastic and dedicated scientist and it's great to see her work publicised in this way! So here is the link:
http://phdcomics.com/comics/archive.php?comicid=1726