Sunday, 29 April 2018

Towards solving some prickly problems with hedgehog conservation

Hedgehog - Photo: Jorg Hempel (Wikicommons)

A talk to the Berkshire Mammal Group April 2018

Dr Phil Baker, School of Biological Sciences, University of Reading

Dr Baker explained that the threat to hedgehogs and the need for their conservation had gone ‘under the radar’ until fairly recently, and now students of this creature were ‘playing catch-up’. He argued that, as conservationists, we don’t have the data we now need to establish scientifically how things have changed. He undertook to set out what we need to know; to establish if there is a decline in numbers and to quantify how much that decline might be; to identify what has caused it and what we need to do to conserve this culturally important species. Phil hinted at controversy, referring in passing to the problems of the human introduction of hedgehogs to island ecosystems, and warned he would be playing Devil’s advocate. Indeed, as a clue, a couple of his many splendid photographs had humorously been annotated with red horns!


First he defined the hedgehog as an insectivore, belonging to one of four groups that comprise the shrews, moles, solenodons and hedgehogs. Of the latter there are 16 species and the talk would be concerned with the West European Hedgehog (though Phil conceded the best hedgehog photographs were those of the African Pygmy Hedgehog.)

Anatomically modern hedgehogs have been found dating from the Miocene – five million years ago – so, when there were no hedgerows! We assume they were edge roaming, perhaps even woodland dwelling. (“Perhaps I should drop my aitches and call them ‘edge’ogs’”, Phil joked.) It is we who have changed the landscape and affected hedgehog behaviour and abundance.

The problem

Hedgehogs of the early modern period, c1600-1800, have been studied extensively by Roger Lovegrove (2007). He examined church records for evidence of animals killed by way of pest control. It was thought by some at the time that hedgehogs would drink milk direct from cows’ udders and steal the yield. However, Lovegrove concentrated on records from ten just counties in southwestern England, concluding that half a million were killed over this period.

In the nineteenth century the human population doubled twice: 9m in 1801 to 38m in 1901. Moreover, during this period game shooting became large-scale and more organised. Gamekeepers were employed in considerable numbers, falling back only after the outbreak of war in1914. Gamekeepers would kill anything that represented a threat to game bird production: foxes, wild cats, pine marten, stoats – even moles! Certainly hedgehogs were included for their likely predation of eggs, or even chicks. The oldest data sets we have date from the 1960s, and these reveal declining numbers of hedgehogs killed on game estates. But there is much less intensive pest control surrounding these estates, so killing predators locally creates a sink effect, with new animals moving in to vacant territories. Changing trap standards represents a threat too. Stoat traps will also kill rabbits and hedgehogs. A study in 2000 indicated they accelerated bi-catch, so the apertures of these traps were narrowed, causing a 75% reduction in kills. But such killing is no longer reported, and how can conservation work if one key group is silent? New self-setting traps from New Zealand have now been introduced and are deemed legal. These will become a threat as they catch animals repeatedly and without human involvement. There is bound to be an effect as stoats’ and hedgehogs’ heads are the same size!

Food shortages and rationing in the Second World War led to another cycle of threat. Farmers were encouraged to maximise food production; hedgerows were grubbed out to aid the efficiency of mechanisation; machines caused soil compaction and a reduction of earthworks abundance; chemicals reduced the number of invertebrates; even rodents were affected. These conditions have caused a reduction in biodiversity across all taxa – similar declines have been reported for flying insects and birds.

The road network has increased by a third since 1950 (especially with ‘A’ roads and motorways), and this has been accompanied by an increase in overall traffic volume.

Interestingly, the badger population, despite persecution and TB culls, has doubled over this time; the number of setts has increased 95% since 1985 and individual groups may also be bigger. But a study by Dave McDonald at Wytham Wood, having looked at pre- and over-winter conditions, indicates the adverse effects of climate change on food. It is much the same for hedgehogs. They have endured a 60-year onslaught!

How bad is it?

There have been several (though surprisingly not many) studies of hedgehog abundance and distribution, of which perhaps the best known was by Pat Morris in London in the 1980s. The classic work, however, was by Maurice Burton, a newspaper journalist in the 1950. Burton estimated from personal observation that in Oxfordshire there was one hedgehog per acre, so perhaps 30m hedgehogs in the UK. This is the questionable backdrop against which more recent surveys have been set.

Distribution was studied by Arnold (1993), but, like later studies, was dependant on the voluntary submission of data.

Steve Harris (1995) at Bristol mined the literature for published mammal surveys and estimated population numbers to 1km squares per land class. He allocated a score to each: 1, ‘excellent’ to 5, ‘very poor’. There were only four studies of hedgehogs to draw upon, and the results spread over 20 land classes. Harris estimated one and a half million individuals, and rated hedgehogs 4: ‘poor’. This work revealed just how much we did not know. And Defra’s recent updates suggest there has been no progress. There are massive gaps in in our knowledge of population and habitat.

The oft-quoted figure of a 90% crash between the 1950s and 1990s suggests – contentiously – that hedgehogs are worse off than tigers! But not everything is as it seems. Burton himself used the caveat, “highly unlikely” when arriving at his headline figure, and in Germany the estimate is a considerable more conservative one hedgehog per 25 acres. It is generally believed there has been a decline, but almost certainly not by as much as the quotations suggest.

We need monitoring programmes, Phil argued, such as those conducted in Hyde Park with thermal imaging equipment, but the cost usually forces us to use alternative means. There have been several ongoing crowd-sourced surveys in recent years, such as those by the People’s Trust for Endangered Species in London and the British Trust for Ornithology in East Anglia:

Mammals on Roads     One a year, reporters drive their usual routes. 3% decline since 2002
Living with Mammals     Garden survey by PTES.               2% decline since 2004
Garden Birdwatch     Mammals are an optional inclusion.       2% rise since 2007

Likewise the Breeding Bird Survey from 1996, for which volunteers walk a transect twice a year. However, these are very partial, reliant on the self-selecting involvement of volunteers and partial submission of records, with no randomisation of samples and no standardisation of effort.

Take the counting of squashed hedgehogs on roads. How does the number reflect population and vulnerability to traffic? Is it true that the more casualties, the bigger the total population must be in proportion; or conversely, that the population must have suffered a decline due to increasing attrition? This becomes more complicated when one realises that, according to a Dutch study, hedgehogs actively avoid roads. Such evidence is borne out by further work at Southampton by Rondini and Doncaster (2002). Also, the access to the evidence is transient as carcasses disappear quickly and so is difficult to verify or even quantify.

Finding an effective technique

To make matters worse, however imperfect the evidence, the conclusions of these various surveys are inconsistent and even contradictory. They simply don’t tell us the same things or even present a coherent trend. While most indicate decline, one (urban) survey suggests increasing numbers. What we need, Phil argued, is a robust technique allied to randomness of application so as to avoid the effects of recorder bias. Equipment should be accurate, cheap and verifiable if it is to keep the public engaged and allow widespread effort.

As gauging absolute numbers appears to be impossible for the present, let’s settle for presence/absence. For this the hedgehog tunnel has been developed, allowing the capture of footprints in ink. However, we must also be aware of false absence; if we have no evidence of presence, how do we know if hedgehogs are not there? We may simply have missed them. How much is apparent absence down to animal distribution and have much to inaccurate technique?

One technique (Williams et al) is to work on a site that is under the management of one person alone. Ten tunnels are set out and checked repeatedly over five days. Tunnel locations are sited appropriately, though it is accepted that the reliance on edges is an assumption. In the reference survey 261 volunteers took part in monitoring rural sites – one of the biggest citizen science projects – while 219 volunteered for urban sites (in Reading). In the latter there was a 32% success rate in 2013 and 40% in 2014.

The urban study in 2013 indicated a 60% chance each day that hedgehogs would be present over the week; and in 2014, 68%. It revealed a tendency for hedgehogs to return each day and suggested that, if a tunnel was in a garden, they’d find it. Indeed, there was a 78% consistency of use. Conversely, if you don’t get inky paw prints, it is because the hedgehog isn’t in the garden. When homeowners where asked if they thought they had hedgehogs, or to predict their presence, 35% got it wrong. Indeed lots of residents thought there were very few in the Reading area, whereas Lower Earley actually has a good population.

Phil expressed himself satisfied with the technique for garden monitoring; it is certainly better than householder perception.

Impact of badgers
Badger sett density has a negative impact on hedgehogs – whereas houses appear to have a positive effect! After you’ve accounted for badgers, there are few impacts of significance. Badgers affect hedgehogs like nothing else does. Just how bad are they?
Actually, this is a more widely studied field, with three studies as a result of the government-sponsored badger cull alone! Hedgehogs don’t tolerate badgers, so after the cull their numbers increased. The lesson is clear: “fewer badgers; more hedgehogs”. Hedgehogs are more present in urban areas than rural, a pattern that reflects badger distribution. Hubert et al (2011) studied the indirect evidence of food supply and concluded that hedgehogs avoid badgers by moving into town, where, coincidentally, people will also feed them!

Why are badgers a problem? Eagles apart, badgers are the most likely source of predation, though no studies have been carried out on the direct effect of predation on the overall hedgehog population. More importantly, they compete for the same foodstuffs. One badger can eat as much as can seven hedgehogs. However, it is not the case that total food supplies have dwindled, as there has been sufficient to support an increase in badger numbers.

Humans have altered the rural landscape and unintentionally made the problem of predation and competition worse. Historically they co-existed after all. Gardens, however, represent a refuge from both. The challenge is to find sites that allow co-existence, but trading badgers for hedgehogs would be a ‘hot potato’, as the reaction to Phil’s earlier comments by some members of the audience made only too clear.

Planting more hedgerows would be one answer, but that would cost large sums and recording multiple sites to get the supporting information. Then farmers would have to be funded in order to make change viable. It would be expensive!


Over-wintering behaviour has been studied in Sweden, where 25% to 40% of hedgehogs die each year. In the UK, survival rates are better: 18%-21%. The University of Reading has studied hibernation at locations near student accommodation in Gloucestershire and Nottingham, using radio tagging. The research has revealed multiple nests, nest movement, moving around a lot before hibernation, but also two or three moves during the period of deep sleep. In one of the studies, 22 animals used an average of 6.5 nests. Good nest sites are required for security, cover, warmth and the abundance of nesting materials. Hedgehogs like to have options, to be able to move if needed. Good quality hedgerows, woodland and brambles offer the best bets. If they get too cold (-5oC to –10oC) they will have to wake up, so climate change is a potential problem as well. Perhaps the urban heat island effect is another reason for the perceived increase in preference for urban locations?

Fragmentation by roads

Hedghogs need help with roads as the width of pavement and the speed and volume of traffic represent considerable challenges. Williams studied the effect of motorways for his PhD and tentatively came to the conclusion that they separated distinct populations that had little or no contact with each other. Populations are already patchy, with more places where hedgehogs are absent now than in the 1990s. And things are getting worse, as the Highways Agency installs solid concrete barriers rather than the old metal ones. The only viable crossings are bridges and underpasses – or purpose-built badger tunnels which come with an inherent danger! But even urban roads are a challenge.

Prospects, especially in town

Suffering poor, fragmented habitat and threatened by badgers, no wonder hedgehogs are heading for the towns! The only ‘good news’ for hedgehogs is the badger cull. (Interestingly the hedgehog hotspots are East Anglia, with a tradition of gamekeeper control of badgers and Yorkshire, with a tradition of badger-baiting.) More hedgerows are vital, but expensive. In the short term we can at least help the urban hedgehog.

It has been suggested that foxes pose a problem and indeed when the foxes of Bristol were suffering from mange a few years ago, hedgehogs appeared more numerous. However, although there have been a hundred studies of foxes’ diet, hedgehogs feature very infrequently. And dogs tend to be indoors at the times hedgehogs are out and about.

We can provide sources of food (but should not offer cow’s milk or mealworms), shelter and access. All sorts of threats can be moderated: litter, fences, rat boxes, bonfires, rubber bands. Decking is not good for food supply, though it is a good source of shelter. Phil noted that gardening and maintenance practice does make a difference. Ten years ago, you’d find plenty in the Harris Garden between 9-12pm, but not since the refuges have been systematically mown. As for holes in fences, 48,000 people have signed up to Hedgehog Street. According to the Earley gardens project (Piper 2016), we locally could do better!

If we double the access, we double the number of hedgehogs. There is no obvious difference in the gardens used. On any one night, a hedgehog might use eight gardens; a female might cover an area of 100m x 100x, or more if mating. So why not use all the gardens available? Fear? We need to radio-track to see whether they use different gardens on different nights. Hog boxes – of which there are dozen of designs – are more likely to make a garden attractive, especially if placed nearer the house! It might take time, for although hedgehogs make repeat visits, their pattern of travel will change from year to year.


•    We are at a moment of crux; hedgehogs are declining throughout Europe and soon to be reclassified as ‘near threatened’
•    We are now getting the data we need and urban areas are increasingly recognised as important
•    Difficult decisions have to be made; it’s in our hands, but we need buy-in from farmers and householders. Funding will be vital to make any wider scale difference.


Phil had promised to be provocative and play the devil’s advocate, and certainly prompted reactions from the floor on a number of occasions during his talk. Where possible, the subject matter of interjected questions has been incorporated into the foregoing account, but there were several others on additional topics, as answered below.

Over the past 10-15 years there has been an upswing in the study of hedgehogs. However, there have been only two studies of diet since the 1970s. There have been no studies of the impact of deer on the density of woodland vegetation, though the question prompted an interested response.

The rehabilitation of injured hedgehogs provides a valuable function, except where the release occurs in an area remote from the hedgehogs home territory.

Tip-ex surveys are a useful way of monitoring the number of individuals in a local population, thought this has raised concerns about the possible need for training and licensing in wildlife handling.

Do hedgehog have fleas? No, not to any significant degree, though some individuals might.

Sunday, 4 February 2018

Hunting Primates in the Amazon

Behavioural Interactions between Humans and Monkeys

Dr Sarah Papworth, Royal Holloway

A Talk to the Berkshire Mammal Group 7 December 2017

Sarah, a senior lecturer in Conservation Biology at Royal Holloway, was introduced as interested in the effects of human decisions and behaviour in complex ecosystems, and particularly having studied hunting in the tropics for her PhD.  Indeed, she had been undertaking fieldwork in the Amazon basin when originally approached to give this talk!  She explained that she would look at contact between the many species of monkey found in Amazonia, and humans – hunters, researchers and eco-tourists.  She would focus on changes in behaviour and note their implications for conservation.



Turning to the map of South America to set her work in geographical context, Sarah explained that despite the great swathe of bright green, there was considerable diversity of habitat in Amazonia; it wasn’t just lowland moist forest as the colouring indicated.  In Ecuador, the locus of much of her research, the forest is ‘terra ferme’ – dry underfoot despite year-round rainfall – while where she works in neighbouring Peru the forest is seasonally flooded.  In these flooded forests, there is heavy rainfall for four months of the year, the level of which varies with El Nino and other climatic determinants.  It is sufficiently pronounced that the high-water mark remains visible on the trees throughout the year – conspicuously above head-height.  In both types of forests it remains dark beneath the canopy.
The human population of the forest was once more numerous, explorers originally entering Amazonia from over the Andes and finding elaborate communities based on cultivation.  It was decimated in colonial times, by the effects of conquest and small pox, and is now smaller and more dispersed. Even the towns can be isolated.  Sarah shared pictures of Iquitos in Peru, the largest town without access by road.  To reach it one has to travel by boat or aeroplane.
But Sarah’s interest was in how humans and primates interact, and in the forest hunting is very much part of the indigenous people’s daily experience.  They hunt deer, peccary and tapir, but monkeys – large bodied and apparently very tasty – are favoured.  Monkeys are also kept as pets and even, on occasion, breast-fed.  A favoured tactic is to kill a mother for food and retain her infant as a pet.  Indeed, such pets can become almost surrogate babies.  Traditionally monkeys feature in story-telling and animist culture, while more recently, they have become the object of eco-tourism and scientific research.

A PhD in Ethnobiology

“Ethnobiology is the scientific study of dynamic relationships between people, biota and environment”
To pursue her interest, Sarah had planned to undertake research for her PhD in West Africa, but civil war intervened and she was forced to find an alternative location.  She simply googled ‘field sites with monkeys’!  Ecuador was a clear option.  Consulting the literature of the more specialised branch of knowledge, Ethnoprimatology, she was advised to start with indigenous societies for which monkeys are an important element of diet.  Ecuador matched the criteria perfectly.
Her research was largely to be conducted in Yasuni National Park, where around 2000 Waorani live in a reservation the size of Wales.  The Waorani’s first peaceful contact with the outside world was as late as the 1950s.  Apparently, they had previously considered strangers to be ‘carnivorous ghosts’ and, feeling threatened, killed the occasional intruder in selfdefence.  As a consequence, they acquired a fearsome reputation.  However, when Sarah first went to Ecuador in 2009, many had settled in villages, maintaining neighbourly relations, though 500 or so still live in isolated groups in the forest.  
The Waorani are notable as monkey hunters.  Traditionally they hunted monkeys using toxins from the poison arrow frog to treat their blowpipe darts.  These would be nicked so the tip would break off if the monkey tried to remove the dart from its body.  A hunter would stand below a group of monkeys and blow the pipe.  Once a monkey was hit, it would be paralysed by the poison and could be retrieved and killed.
Monkeys There are 11 species of monkey in Yasuni, including the Capuchin, Howler and Owl monkey, Saddleback tamarin, Saki, Squirrel, Spider, Titi and Woolly monkey.  The locals identify three types of ‘night monkey’, rather to Sarah’s initial confusion, but two (the arboreal Olingo and Kinkajou) are not actually primates, despite having grasping hands.  None-the-less, these and the Owl monkey form a coherent ethno-taxonomic group, however defined by science.
Early on, Sarah surveyed the culturally salient species, those that were repeatedly named as important.  First, and conspicuously the most important, was the Woolly monkey, followed by deer and peccaries, then the Spider monkey, several other creatures and the Howler monkey.  It would seem that monkeys were not, per se, more significant than other types of animal, but their value varied according to species.
Ref: Papworth et al (2013) ‘The natural place to begin’

The reaction of primates to predation

There is scholarly debate on the long-term impact of hunting.  While it clearly is disastrous for the individual animals concerned, hunting does result in habitat protection.  (Richard Bodmer et al (2008), chapt 8: ’Wildlife and Society’).  However, Zuberbuhler argues that human activity is too recent to be evolutionarily relevant.
Nonetheless, humans are highly effective hunters, especially with (silent) blow pipes, with which entire groups of monkeys can be killed on one expedition, rather than (noisy and disruptive) guns, which, after the first death, alarm the other monkeys and drive them away.
How do primates reactions to predation?  Sarah turned to the example of monkeys in Africa.  In the case of an approach by an ambush predator, such as a leopard, the male descends to attack and draw attention while the females and infants climb to safety.  In the case of an eagle, threatening them from above, the monkeys descend from the canopy to seek protection below.  Likewise, monkeys need to react quickly to predators.  Sarah referred to the example of Howler monkeys in Panama whose experience of the Harpy eagle was minimal.  When the eagles returned to the locality after an absence of 20 years, the unwary monkeys were tempted to approach them and thus became vulnerable to ambush.  It took a period of only six months to adapt and learn to keep their distance.

Woolly monkeys’ response to hunting

The Woolley monkey: Lagothrix Lagothricha

Sarah’s research into defensive behaviour was based on Woolly monkeys.  The Woolly monkey, she explained, lives in large groups, eats fruit, seeks and leaves, is about 7kg and has a prehensile tail.  In gauging the likely response of Woolly monkeys to predators in Yasuni, Sarah anticipated they would resort to silence, low visibility and collective group behaviour, avoiding the attention drawn by individual responses.  
Her investigation involved researchers dressing and behaving respectively as three categories of human, each representing what was assumed to be a decreasing level of threat: hunters, gatherers and researchers.  It was expected that the monkeys would respond to hunters, and ignore the unthreatening behaviour of gatherers and researchers.  The results supported the prediction, in that the appearance of hunters prompted the biggest reaction, but the monkeys also reacted to the presence of gatherers and researchers.  It was thought that perhaps the intensity of observation by researchers might be interpreted by the monkeys as threatening, or perhaps their positioning below the monkeys emulated that of the hunters?
Ref: Papworth (2013) ‘Hunted Woolly monkeys’
To explore the possible impact of monkey caution toward researchers on the accuracy of population studies, Sarah’s research student Camila Blasi-Foglietti is currently undertaking research in West Africa, investigating how behaviour might lead to under-estimation of monkey populations in known hunting areas.

The impact of human presence

The work of Geffroy et al (2015) suggests that human presence and their feeding of animals leads to the habituation and emboldening of other species, and affects their reaction to predators.  This might manifest itself in a couple of ways:
• Through selection prey species become bolder, therefore less fearful of, and more vulnerable to, the predator.
• The ‘human shield’ effect is whereby the predator becomes more wary of man, and so the prey becomes bolder as the threat to it diminishes
The evidence to support either hypothesis is inconclusive, so Sarah undertook research into the impact of (non-predatory) behaviour by both eco-tourists and researchers, based this time in Peru.  In contrast to Ecuador, the sites in Peru were flooded forest.  Moreover, the monkeys in the new research area were different from those in Ecuador: the Saki is different; there are two species of Spider monkey, not one; and the Owl monkey might be a different species.

Proximity –  Capuchin monkeys’ response to researchers

The test species was the Large-headed Brown Capuchin, a placid species, unlike the more aggressive White-fronted Capuchin.  Taxonomical designation is fluid, but the latest Latin designation (checked, we were assured, that very morning) is Sapajus macrocephalus.  The Capuchin is cat-sized and frugivorous / insectivorous – though some have been known to eat infant tamarins. They live in mixed groups of 15 to 20 individuals and associate with the Squirrel monkey (which lives in groups of up to 100), though the basis of their symbiosis is unclear.
This past summer’s research (2017) suggests that proximity to humans is not correlated with vigilance, and graphs were displayed to illustrate the point.  Are humans acting as a shield? It is not yet clear, but Sarah did relay an anecdote in which a Harpy eagle was present, indeed very close to the researchers, but did not attack the monkeys.  However, at present, the results of this research are merely preliminary.

Noise –  Pygmy marmosets’ reaction to eco-tourists

Pygmy marmoset, Yasuni National Park 2010
The Pygmy marmoset is the world’s smallest monkey.  They live in family groups and, unusually, pairs have twins twice a year.  The parents are aided by their sub-adult offspring, who thereby gain parenting experience in anticipation of having families of their own.  Pygmy marmosets are gum specialists, boring holes in clusters of three or so trees that constitute their home area, and rarely straying far.  Because of this constraint they are easily observed and can be counted with reasonable reliability.
How do they respond to eco-tourists, whose presence is brief and irregular, unlike researchers who tend to stay in the locality for a period of several months?
The continuing presence of marmosets is good for tourism, and reflects well on the marmoset’s life experience.  But what about the noise tourists are apt to make?  Surprisingly there is no evidence in the literature.  Sarah’s research relied on playing recordings of human speech to the marmosets, varying in volume from whispering and talking to shouting, and for both short and long durations.  In a rather picturesque detail, Sarah explained that because the forest was flooded, the recording equipment and speaker were mounted in a canoe!
The results indicated, perhaps unsurprisingly, that the Marmosets ignored quiet or conversational voices, but ran away if they heard shouting.  The median time elapsing before return was five minutes.  Results were plotted at 30 dB, 60 dB ad 78 dB – the monkeys’ reaction doubling in intensity between the latter two levels.  It was clearly the volume, rather than the presence of humans that was disturbing them.  Sarah’s conclusion: don’t shout at monkeys!  This, though seemingly obvious (on her own admission), will be used to reinforce the advice given at the education centres associated with eco-tourism.
A lively discussion followed, both in the form of questions from the floor and informal discussion after Sarah had been thanked for an engaging talk on a very interesting topic.

What is the size of monkey population and has it declined over the years? The population is not quantified in absolute terms, but from modelling it doesn’t appear to have declined in recent years, and with such a small human population, hunting is maintained at a sustainable level.

Is hunting practiced by both the sedentary and forest-dwelling Waoroni? Yes, as far as is known.  Certainly, the sedentary Waoroni continue to hunt.
What proportion of Waoroni diet is accounted for by hunting? Actually, around 50% of protein is from fish. Fishing is popular because it is a sociable rather than silent activity.  There is also some traditional shifting agriculture within the forest.
Are monkeys alarmed just by the volume of speech, or does the difference between languages play a part? This is very much of interest, but yet to be tested.  (The Waoroni, incidentally, mostly speak Spanish, or are bilingual; Sarah has learned Spanish though not Waoroni)
Is it the props (the blowpipes) or behaviour of hunters that the monkeys react to? Not clear, but more probably the latter.  This would explain why the positioning and intense observation by researchers – which mirrors that of hunters – also causes alarm.
Edwin A.R. Trout Berkshire Mammal Group

Thursday, 13 July 2017

Saving the Slow Loris

Saving the Slow Loris through Research & Education in south-east Asia

Stephanie Poindexter and Claire Cardinal of Oxford Brookes University

A Talk to the Berkshire Mammal Group
3 November 2016

Explaining that the advertised speaker, Professor Anna Nekaris of Oxford Brookes University, was unavailable but had kindly arranged substitutes from her research team, Edwin introduced the two guest speakers and thanked them for stepping in. They were to present on complementary aspects the originally agreed theme – the plight of the Slow Loris – illustrating it with reference to the field studies they had individually undertaken for their degrees. Stephanie was a PhD student (originally from the USA) and would present first, followed by Claire who had recently completed her MSc in Primate Conservation.

Cognition and Conservation: measuring spatial cognition in Slow Loris and its application to reintroduction practices in Vietnam, Thailand and Indonesia

Stephanie Poindexter

Stephanie set a sadly familiar scene of population depletion and defined the slow loris as a small nocturnal primate present in southeast Asia. There are nine species of loris in all, of which Stephanie was studying the Pigmy Slow Loris and the Bengal Slow Loris.

Clearly fascinated by her subject, Stephanie described some of their distinctive physical attributes, unusual aspects of their ecology that make them so interesting a species to study. They are conspicuously exceptional in their consumption of gum. They are reliant on a diet primarily of insects and tree sap and gum that is available all year round, supplemented by seasonal nectar. They grasp branches for hours without numbness or tiring. They are unusual among mammals in having periods of torpidity, and are the only primate to be venomous.

Yet there are many threats to the population, and human consumption is the most destructive: captured for the pet trade, used as photo props, and killed for the preparation of traditional medicine. Also deforestation has reduced their natural habitat.

Stephanie’s research was into translocated individuals – those taken from the wild as pets or roadside rescues, taken to a rescue centre and reintroduced to the forest. It sounded a promising idea, but reintroduction can’t be rushed without detriment to the animals. Stephanie was to see how they adjusted, how, or indeed whether, they could re-assimilate.

Her work was based in two locations: The Little Fireface Project’s field station in Java, Indonesia (mainly agri-forest, but where at least the farmers would mark their field boundaries with the gum trees favoured by the slow loris), and Cuc Phuong Nah in Vietnam. This offers scare resources, but has been a protected area since 1993, supported by Frankfurt and Leipzig Zoos. Beside the Bengal and Pygmy Slow Loris, other vulnerable species there include the pangolin and langur. Stephanie spent five months in 2015 monitoring returned lorises and their range.

One of her subject species, the Pygmy Slow Loris, weighs a mere 400 grammes. It has seasonal coats that are distinctly different. Indeed its pellage originally suggested two separate species! It is endemic in Cambodia, Laos, China and Vietnam (but not Thailand where it has appeared but recently as result of human intervention). However, there are distinct genetic populations and so DNA testing is important to establish the historical range of individuals before their reintroduction. This is complicated further by the distinction between north and south populations within Vietnam, and so caution should be observed.

In order to monitor individual lorises, radio collars are fitted for 11 months and over time their movements can be tracked. It has become apparent that male and female home ranges overlap, suggesting promiscuous mating, whereas the home ranges of other species are often more distinct. The home range of slow lorises is roughly 20 hectares. However, reintroduced individuals fail to stabilise their range, which may be as large as 80 hectares, or four times as large as those raised in the wild.

Why, what is missing? What are they looking for? Possibly they looking for the type of home range whence they came originally. Natal Habitat Preference Induction analysis is the tool used to explore this proposition, and spatial cognition is the subject of Stephanie’s PhD.

Her data recorded, Stephanie moved on to Indonesia, to the Little Fireface Project’s field station in West Java. The project (LFP) was founded in 1993 by Anna Nekaris, and the field station in 2011. The staff covers a range of disciplines, including someone responsible for maintaining a positive presence on social media. The station’s motto is ‘Ecology – Education – Empowerment’, and over the past five years the team has collected a huge amount of data and learned quite a lot about the slow loris:
  • Their dimensions vary considerably: 21-31 cm in length, 125-2,000 grammes in weight.
  • Besides gum and insects, they feed on the nectar of flowers. Are they pollinators? They don’t appear to damage the flowers, so it is thought they might be.
  • When not sleeping they are more social than expected, interacting and communicating relatively often. Social foraging, particularly when the flower component of their diet comes into season.
  • They have one or two offspring a year after a six-month gestation. Infants stay with their mother for 16-18 months before dispersal and this is an unusually long period for a mammal of this size. Now first baby has borne her own baby, the full cycle of life has been witnessed.
  • The slow loris is venomous, with saliva and brachial gland secretions. Buy why? Is it a predator avoidance adaptation? It seems that slow lorises cover themselves with brachial secretions when setting out to forage at night, so that hypothesis is supported. It is widespread practice in Indonesia to trim or remove the loris’s teeth in captivity to avoid venomous bites, and when Stephanie showed four photographs of a researcher’s face swelling after being bitten, it was easy to see why.
This is scientific study, however; how do the locals regard them? A positive view is important to the loris’s long-term survival, so the field station runs an education programme to cultivate local attitudes.

The project has helped fund a local school and once a week runs a nature club for the children. The idea is to encourage them to value the wildlife of their locality, and especially the slow loris. LFP has published a picture book entitled Forest Protector, which is now available in German and the languages of Indonesia and Vietnam. The pictures are by the illustrator of Family Guy, Shelley Low (whose name – appropriately, if rendered S. Low – reflects her subject!). The participating children are asked to draw a picture or tell a story, and by the time the programme finishes marked changes in perception can be observed.

LFP also works with university students on Java. Placements are offered, and after participating in research work, the students give a presentation to others on their return to university. Judging science fairs is one of several other ways the Project has become involved in local education. It is a long-term investment.

Other areas of conservation activity

Monitoring fairs
Monthly market fairs are held in popular hotspots like Bali. Volunteers visit them repeatedly, but discreetly to gauge number of lorises and other animals involved in the trade.

Photo props
Lately as many as 10-15 animals can be paraded every day on social media. This is a conspicuous increase driven entirely by the huge growth of social media phenomenon itself.

Traditional medicine
Slow lorises are traditionally regarded beneficial for around 100 ailments, and are given to pregnant women to confer strength to their unborn babies, and placed under houses for good luck. The emphasis on medicine is particularly strong in Cambodia and Laos, though less so in Vietnam and not in Thailand where the slow loris wasn’t historically present.

This is difficult to fight, as Stephanie herself acknowledged. Creatures are pushed to higher altitudes (currently 1,300-1,700 m above sea level) to avoid the activity of farmers who are themselves being pressed to colonise new land. The field station has established a plant nursery to breed gum tree saplings. Farmers will accept free saplings and use these beneficial species as boundary markers, so a source of food remains available to the loris.

Next steps
Further studies are in preparation, as the field station is intended for on-going research. Vocalisation is a new area of interest, and recently acquired thermal imaging cameras offer new possibilities. The Project envisages more market surveys and more work with TV – several documentaries have already been made, including Jungle Gremlins of Java (which was to be shown on BBC 2 the following Saturday). For further information:

Communicating Conservation: using acoustics and education to develop understanding endangered Slow Lorises
and Gibbons in Vietnam and Java

Claire Cardinal
Claire opened by saying she had wanted to make a contribution to conservation so undertook two studies for her MSc – admitting she had probably bitten off more than she could chew. Like Stephanie’s, her work lay in the twin fields of research and education:

  • Whoop Troop – an education programme using puppetry
  • An acoustics study of the Pygmy Slow Loris

Claire’s education work was spread over two locations: LFP in Java and the Dao Tien Centre for Endangered Primate Species (set up eight years ago by Monkey World to protect slow lorises and gibbons).

Her objective was to create and evaluate a new educational resource, and establish whether it would be flexible to use as a template in different countries and for different species. As 70% of Asian primates are threatened, according to the IUCN Red List, human attitudes and behaviour need to change if they are to be saved. Knowledge and affinity are, therefore, an essential first step. It has been found that negative messages don’t help – they engender a rather hopeless sense of “well, what can we do?” It is better to provide positive messages of “awe and wonder”.

The project planned to present a three-month course to rural teenagers (aged about 12-14), a neglected audience for such work, and would compare its effect on participants in both Java and Vietnam. It would include a science component to develop interest and knowledge, and puppetry to engender affinity. Students would be asked to write and perform puppet shows – and at this point Claire demonstrated the use of two large naturalistic glove puppets.

Coverage was extended to six native animals – both countries share a common biosphere – including: the Javan Rhinoceros (of which there are only 50 left in the wild), Saltwater Crocodile, Leopard Cat, Rhinoceros Hornbill and Eurasian Hornbill. In Java the selection would included the Java Slow Loris and Silvery Java Gibbon, and in Vietnam, the Pygmy Slow Loris and Golden Cheeked Gibbon.

Data Collection
As the purpose of the project was to evaluate impact, it was important to find methods to measure the impact of ideas across the three schools and eight puppet shows. Claire turned to the techniques of social science.

By showing photographs and getting the children to write down what they thought of the subject, Claire had free access to potentially revealing terminology, from which she could form ‘word clouds’ in which frequency could be depicted graphically.

Cultural Domain Analysis
The technique assesses shared beliefs and knowledge. Are the participants thinking the same way? As the only commonality between the groups of students was the course, the results would (and did) show that they had learned something from it.

Comparing statements made before and after the course, the importance of each word, based on frequency and average rank, could be established. If present, the course had taught participants something.

Content Analysis
Words were colour coded for ‘emotion’ and ‘knowledge’, or as ‘neutral’. After a course of creative writing there were far fewer neutral words. The change was indicated by a graphic depiction not unlike the election swingometer. Afterwards there were more empathetic, anthropomorphic and taxonomic words, and fewer emotional ones.

Such analyses suggested the effect of puppetry justified the study and such programmes would be useful as a tool in conservation education. The long-term impact is yet to be established – only time will tell – but Claire was pleased to report that after one school visit a girl in the audience arranged for her grandmother’s pet gibbon to be returned to a rescue centre – so a tangible short-term effect in that instance!

Acoustic Study
Claire admitted this was work in progress, with lots of data yet to analyse. The objective was to establish whether the Pygmy Slow Loris vocalised at an ultrasonic frequency. This is a new field of research, not studied before, and so is at the cutting edge. If successful it would provide a useful new tool for population monitoring, as the slow loris is difficult to find by visual means alone.

The task of acoustic monitoring has been made easier by technical advances and the equipment Claire used included: a bat detector, directional microphone and specialist software for birdcalls that transferred recordings into sonographs.

While in the field Claire would spend six hour shifts three nights a week sitting in the forest recording ultrasonic sound, monitoring released and captive Pygmy Slow Lorises in southern Vietnam. She described her time in the forest as feeling safe and secure on an island, hearing the insects waking up at 4am, and gibbons at 5.30.

The forest comprised dense thickets of bamboo growing back after the ravages of the Vietnam War, so Claire would use GPS to pinpoint the loris’ sleep sites, then monitor movement from a static, sedentary position. She now has 60 hours of ultrasonic recording, which she is still going through. The task is made more complicated by the higher frequency calls bouncing off trees; she showed us sonographs that could just as plausibly have been made by bats or insects. As she said, it is work in progress, with more report in future!

Project Splatter

A talk by Dr Sarah Perkins to the Berkshire Mammal Group
9th February 2017
Dr Sarah Perkins is a wildlife biologist at Cardiff University, having started her career as a conservation officer for the UK Wildlife Trust. In an entire year of working as an Otter Conservation Officer, Sarah only ever saw one otter – a road-killed one – and became interested in quantifying the number of animals killed on the roads each year. She worked abroad for several years, working on wildlife diseases, before returning to the UK and taking a position at Cardiff. There her interest in the number of animals killed, which species are the most vulnerable, and whether there were hotspots of roadkill that could be mitigated against, led her to establish Project Splatter in 2013, as a collaborative citizen science project – the subject of her talk to the Berkshire Mammal Group.

Sarah opened by acknowledging that road kill is a common sight and asking generally how we engage with wildlife, and what the impact of roads might be on animal mortality. She turned to the journal, Science, which in December had published a paper on roadlessness. On screen was a map plotting the incidence of roads in red, lined with 1 km buffers into the surrounding habitat, and the road-free areas in blue, in which roads would have no effect on wildlife. 80% of the globe is still roadless, but much of this area is composed of the Arctic regions, the Siberian tundra and deserts in north Africa and Australia and other inhospitable environments. And the rest is divided into 600,000 fragmented habitats, half of which are less than 1 km in extent and only 7% are of the largest size category). Only 9.3% are protected areas. So the clear conclusion was that roads have the potential for a major impact on wildlife and its habitats.

The scale of road deaths

What might be the scale of wildlife road deaths, she asked, pointing to illustrative graphics: 100s, 10,000s, or 1,000,000s. Answering her own question – after an uneasy pause – Sarah said we simply don’t know, but can look at studies in other countries that have measured the effects direct vehicle collisions. They propose some dramatically varying estimates:

USA 80m birds killed on US roads per annum
Netherlands 0.2 – 2m birds
Belgium 4m
Denmark 8.3m
Spain 100,000

In the UK a PTES survey was launched in 2001, which has since measured mammals on roads for a period each summer. Usefully it has reflected the decline of the hedgehog, and also picked up a fall in rabbit numbers. But this survey is just in the summer, and just of mammals. Were there any other figures? Well, yes, Deer Collisions ( estimates 42,000 to 74,000 collision deaths a year, information drawn from police and insurance reports. The Mammal Society has produced estimates of 50,000 badger deaths a year, and 100,000 fox deaths. For birds a BTO Road Deaths Enquiry in 1960, at a time when there was rather less traffic than now, concluded a total of 2.9m avian road deaths. Sarah noted it took until 1965 for the figures to be published.

Project Splatter

To draw together contemporary data on all species, Sarah introduced Project Splatter as a continuous, UK-wide survey, set up in January 2013. She explained that it started out as a final year project, undertaken with some reluctance at first by Sam Stafford, an undergraduate reading Zoology at Cardiff. He devised a social media to capture direct reporting by members of the public, and such was its early success that he become highly motivated and earned the soubriquet, “Splatter Sam”. This early success was cemented by the involvement of the press, in particular the publication of a two-page, full colour spread in the Independent, prompting
wider media attention. It was, in Sarah’s words, “a fantastic start”.

The social media platform is designed to make the task of reporting simple and accessible. Reports can be sent in by iPhone app, Android app, Facebook, Twitter and by email or through the web. The scheme accepts both occasional and regular reporting – there need be no on-going commitment, though many of the 2,000 participants are regular contributors – and on Monday the project offers feedback, drawing attention to some of the quirkier reports.

The project’s purpose is to quantify and map British roadkill, determining which species are the most observed, and identifying spatial and temporal hotspots: the ‘where’ and ‘when’. It aims to raise awareness of the roadkill problem, and encourage mitigation (such as green bridges). Ultimately it seeks to reduce the negative impact of roads on wildlife.


To date, Project Splatter has accumulated over 35,000 records. These include 33 mammal species, from shrews to wild boar, and these represent 62% of the records.. Representing another 34% are the 74 bird species, from blackcap to buzzard. There are very few reptiles and amphibians. The five species most recorded as roadkill are:
15% Badgers
14% Rabbits
11% Foxes
7% Hedgehogs
7% Pigeons

And as for distribution, the records come from throughout the country, probably reflecting abundance. However, any analysis needs to account for reporter bias; there are few reports from the Highlands of Scotland, whereas Sussex generates more records than any other county. (There, a paramedic has been involved from the start and is a prolific provider of records.) Double counting is not considered a problem at this stage; with 2,000 reporters and 8,000 reports a year, there are simply not enough reports for duplicated to occur to any degree.

A map of the county indicated ribbons of reports along the M4, A34 and Vale of the White Horse, with a cluster around Newbury and a broader blanket of sightings to the west of the Thames around Abingdon.

In Berkshire pheasants are the most prevalent casualties, at 39% of reports compared with 23% nationally. (At 25% for badgers the local and national tallies are in line, though other species tend to be under represented.) But what do the figures suggest about pheasants’ behaviour. A graph of the monthly figures produce a peak in September and October, when na├»ve young birds are released, and in March, when feral pheasants escape into the countryside.


Using SaTScan models, the Project has identified nine county clusters for mammals, some comprising single species and some of multiple species. There are obvious clusters, such as for badgers in Somerset, where they are presumed to relate to animal abundance, while others are as yet unexplained, such as the concentration of rats in northern England.

For birds there are seven such clusters. An analysis of these suggests some behaviours tends to endanger certain species. Blackbirds, for instance, have a tendency to last-minute flight from possible predators, and a low, undulating flight pattern, and so are innately vulnerable to vehicles. In discussion afterwards it was noted that, conversely, crows have an enhanced ability to judge the paths of approaching danger, and avoid on-coming vehicles.
Sarah asked which roads were the most deadly: Motorways, A roads or B roads. The answer was A roads. Is this the effect of lighting, she wondered, increasing visibility and causing animal avoidance? Hedgehogs were cited as an example of a vulnerable species, falling from 30m in 1950, when there were far fewer motorways and major roads, to 1.5m in 1995. 20-40,00 are killed on roads per annum – far too high a figure.

Peak reporting is in September, July and April, with winter the lowest. Perhaps unsurprisingly the peaks coincide with seasonal breeding and dispersal activity, while many creatures hibernate during the winter. Yet this varies from year to year, according, in part to temperature and the weather, which affects activity and therefore vulnerability to vehicles.

Disappearance of carcasses

It is accepted that scavengers clear carcases and therefore evidence, so establishing the rate of disappearance would give a useful correction factor when analysing the figures. One early study was by Fred Slater, who set out chicken carcasses and measured the tracks of scavengers left in a surrounding sand pit. He established the rate of disappearance was rapid, suggesting that reporting was underestimated 12-16 fold.

To extend this research for the project’s own purposes the University of Cardiff undertook to study the rate of disappearance. Chicken heads were distributed by student Harry Williams at twelve locations around the city, with camera traps set up: some in parks, some in streets. As an amusing aside, Sarah recounted how some of the cameras disappeared, then reappeared, many with footage of puzzled residents investigating the device, and then, having realised what it was, putting it back! The survey was carried out both day and night, and recorded 120 sessions.

Six principal species of scavenger were identified: corvids, foxes, dogs, cats and gulls. How long it took for the carcasses to be taken varied according to the time of day: in the daytime it was very quick, but at night it tended to lie untouched until at dawn, when scavenging was dominated by foxes and domestic cats. Quantifying that, it was established there was a 75.8% chance of removal within 12 hours. On average it took 2 hrs, 13 mins in the day; 8 hrs and 47 mins at night.
To illustrate which scavengers eat carcasses, Sarah showed a short video made up of day and night-time footage from the camera trips. During the day there were plenty of corvids (crows and magpies), cats and dogs; at night, there were rats, foxes, gulls, magpies and – surprisingly – wood mice (visible mainly by their large reflective eyes). Urban foxes were brazen, while rural foxes markedly more timid.

Associated Research

Project Splatter’s records are considered open source and available to share, and so feed into several other studies. Among these are the records of polecats, which are sent to the Vincent Wildlife Trust to help monitor the expansion of this species out from central Wales. Records have been used to help with mapping invasive species, eg Wallaby in Surrey; Wild Boar in Bristol. But perhaps the most systematic is the 20-year-old otter project run by Liz Chadwick, also at Cardiff University. 

Cardiff University Otter Project
In this project otter carcasses are taken to Cardiff for post mortem examination, where the livers and kidneys are checked for contaminants in habitat, parasites are identified, signs of fecundity noted. Rather sadly, Sarah noted the discovery of four nearly full-term foetuses that had died when their mother had been hit. The results of post mortems contribute to various study programmes, the decline of eels and the presence of Toxoplasma gondii, for instance. The otter is a sentinel for watercourse purity and so much can be gained by their examination.

Dead or Alive
A spin-off project, entitled ‘Dead or Alive’, was set up to quantify popular interaction with wildlife; do most people see wildlife alive, or just as roadkill? The project conducted a four-week survey, eliciting 1,400 responses! To take one of the top five roadkill species, the badger, it was possible to establish that 7% of respondents had never seen one, but 88% had seen one dead. As few as 5% had only ever seen live badgers.

Only seen alive Ever seen dead
5% Badger 88%

Respondents were invited to leave comments too, and the responses indicated a high level of concern about the spread of invasive species.

Roadkill Sub-culture
Touching on an interaction of a more unusual nature, Sarah spent a few minutes describing some aspects of roadkill’s place in art, design, clothing and food. She pointed to the activity of ‘freegans’, those who eat roadkill, and the existence of roadkill chefs and ‘badger balti’. She illustrated some of the work of Adam Morrigan, the roadkill artist, and of Jez East/ton Design


Returning to Project Splatter, Sarah drew together the various threads of her talk, summarising the role of roadkill research as a contributor to:

  • Conservation
  • Understanding populations and behaviours
  • Academic research, eg. the otter project
  • Identifying habitat contamination
  • Mapping invasive species
  • Public engagement

She ended by urging the audience to get involved, and supporting imminent moves for new legislation being led by Wendy Morton MP: the Local Authority Roads (Wildlife Protection) Bill.