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.

Thursday, 19 January 2017

Mink – Evil or Interesting?

A Talk by Dr Joanna Bagniewska to the Berkshire Mammal Group

6th October 2016

write-up courtesy of Edwin AR Trout, Berkshire Mammal Group

Dr Joanna Bagniewska, University of Reading

Opening the meeting Amanda Lloyd introduced Joanna as a zoologist specialising in behavioural ecology and invasive species research, gaining her MSc and PhD from Oxford University. Over the years she has undertaken research in five countries, having studied foxes and jackals in South Africa, wombats and wallabies in Australia, mole-rats in the USA, and both bees and mink in Britain. (Joanna observed that in view of mink’s past fortunes, she was one of few researchers able to wear her study species!) Currently Joanna works as a teaching fellow for the School of Biological Sciences at the University of Reading and has won awards as a science communicator.

She started by suggesting she was one of a minority in this country to admire the otherwise widely denigrated American mink, perhaps because she approached the subject from the point of ecology rather than conservation and control (where mink are considered pests). She defined them as mustelids and took a few moments to outline their ecology.

Mink Ecology

The American mink is native to North America, at least north of the south-western arid zone up to and including Alaska, but south of the high Arctic. Mink are to be found in areas of high water quality. They are small bodied – at 15-18” the males are twice the length of the females – and sexually dimorphic. In some areas males have shown a preference for eating rabbits (for which they have proportionately bigger jaws and teeth) and females – water voles. They are opportunistic feeders and both sexes will eat insects, fish and birds.

While native to North America, they have been introduced into Europe, Asia (especially Siberia) and South America (Patagonia in particular),

largely as a result of the former demand for their fur. In the 1920s and ‘30s they were farmed, but later, in the 1950s, many escaped or were released. They are now regarded an invasive species.

They have, in many ways, become too successful for their own good. Why? They are generalist foragers, with a broad diet: birds, amphibians, reptiles, rodents, insects, and crustaceans. They can hunt like foxes, climb like cats and swim like an otter. They are semi aquatic and very adaptable.

An Invasive Species

As an invasive species, what has been their impact? Traditionally, successful incoming species upset the balance of nature by:

  • Increased predation
  • Resource competition
  • Hybridisation
  • Disease transmission

Of these the first two are of most relevance, though there have been some recorded cases of interbreeding between wild and released mink in North America.

The problem of increased predation is exacerbated by the higher proportion of carnivores among invasive species. Carnivores make up 5% of mammalian species, but when invasive mammals are examined, that proportion rises to19%.

Direct predation by mink is most notable in the UK in the case of water voles. Female mink are the right size to enter voles’ underwater holes and the water vole population is declining fast. This is, admittedly, for various reasons, but the presence of mink is not helping. There is no problem with water voles in Europe, incidentally, but rather the Pyrenean Desman instead is vulnerable and declining.

The Landscape of Fear”
Other vulnerable species are ground-nesting sea birds, for which the security of islands and rocky

outcrops are no protection against the semi-aquatic mink. On arrival in a colony mink will behave like ‘a kid in a candy store’ and take as many as 100 chicks per night, with no sense of forward planning or restraint. Indirect consequences follow, as birds leave their nests – in fear or to protect their young by attacking predators – and the chicks or eggs succumb to the cold or neglect. The very presence of fear can have further negative effects on the predated population.

Over-sized, Over-sexed and Over here”
A notable impact of resource competition has been on the European mink, which is now limited to Estonia and the Pyrenees, as the American mink is sufficiently well equipped to out-compete.

American European
1310.2 g v. 976.6 g
size of female = size of male
litter of 6 v. litter of 2.5

The American mink is voracious and adaptable, and its European cousin is unable to keep up.

Another measure of its success lies in the competition with polecats and otters. When these species were declining in the 1920s-50s, mink expanded into their vacated niches, on both land and water.

Horrible – but Interesting

American mink are semi-aquatic BUT …

  • They are small, with a large surface area, and so loose heat quickly
  • Their fur is neither buoyant nor insulative
  • Their propulsion is inefficient – they swim like dogs rather than otters
  • Their paws have little webbing (more than polecats, but less than otters)
  • They have poor eyesight, especially underwater.

Is swimming innate and instinctive? It seems the young have to be taught, as indicated by trials on captive mink. Other tests suggest mink will work harder to get to water than even to obtain food! And mink spend much of their time in the water, diving for food.

Diving Behaviour

How do we study diving animals? It has been difficult until now. Research has focussed onterrestrial behaviour, which is more readily observable and can be indicated by footprints, scat and camera traps. For wild mink only ‘surface events’ have been traceable in the water, and underwater behaviour monitored only in captivity. Joanna’s research was the first monitoring of mink diving in the wild. Indeed, the only previous study of mammals was one of the platypus in Australia. Since then there have been studies of water rats and beavers as new data-logging technology becomes available. Devices small enough to be attached to mink can measure time spans, temperatures, pressure and acceleration.

Such data logging was first developed in the 1950s, weighing as much as 1.5 kg, based on ‘egg timer’ technology and recording output on paper. The first devices were used on Weddell seals. They were accurate to about 20 m and therefore only useful for extensive depths at sea. Now devices are digital, weigh 1g and are accurate to 3 cm, so may be used effectively in the shallow water of British rivers.

Monitoring Programme
Joanna’s project monitored 16 distinct animals on the rivers Thames and Cherwell in Oxfordshire, generating 20 datasets, with a mix of males (six) and females. The programme was conducted over three seasons, spring being excepted on animal welfare grounds.

The method made use of mink rafts, by which an enticing ‘home’ or tunnel was placed on a floating platform away from the bank. Pliable clay would be spread on the base of the raft to receive the impression of foot prints should a mink investigate the tunnel. With the presence of mink thus established, the tunnel would be fitted with a trap and bait, and, if caught, the mink fitted with a collar and data-logger.

Quantitative Results
The collective results of the study indicated great variety in depth and duration, with a total range of 1 to 189 dives per day, with the greatest individual range between 5 and 143. It became notable that the smaller females were the more energetic divers, performing over 100 dives per day (as explained below). The time spent diving wasn’t long: a total of just 38.4 minutes per day on average, with 57.9 seconds the maximum individual dive-length recorded. Median depth times varied between 7.4 and 18.0 seconds.

(Previous studies had suggested even shorter times.) Diving was undertaken throughout the year, not just in summer as had been postulated, and 83% of dives took place in daylight – presumably in consequence of minks’ poor eyesight. The maximum depth of around 3 m was more an indication of river depth than diving ability.

Dive Clustering
The pattern of surfacing suggested that dives were clustered in bouts of activity and so was analysed according to the Hidden Markov Model (HMM). Three types of diving frequency were identified:

  • A “cluster” of multiple dives
  • Loosely aggregated: an “activity session”
  • Single or terminal dives

Temperature and Persistence
Mink experience a temperature range of 5-35 oC, in which temperature falls during activity. The body cools in water, and warms through when basking on the bank; it is typically 35 oC when sleeping, in the 20s when on land, and drops when diving. It is noticeable that dive effort is higher in females; female ‘persistence’ may extend to performing 80 dives in a row. Is this because they are excellent divers, or ineffective hunters who have to repeat dives to eat?

Either way, the smaller the mink the greater the persistence and this may be expressed as a negative relationship between temperature and bodyweight. Persistence is greater during the day, when temperatures are higher, and become more concentrated the shorter the day. That said, mink tend to be inactive 80% of the time, spending only 50 minutes or so in the water per day. Males are more nocturnal – perhaps, because of their size, they are less afraid of meeting otters?

Competition with Otters

Behaviour has altered over time, with the evidence of scat declining since the otter’s resurgence in the 1990. However, if other evidence such as footprints is taken into account, it appears that mink remain, but are no longer deliberately marking their territory. Otters are bigger, and may weigh 8 kg, so while the feisty mink might be prepared to fight, it wouldn’t,

wish to make a habit of it. So what seems to be happening is that when the nocturnal otter returns, mink behaviour adapts to the new circumstances and becomes diurnal, thus avoiding confrontation.


The survey testifies to the success of new TDR (Time Depth Recorder) technology and HMM techniques in monitoring the behaviour of otherwise difficult to observe species.


Have there been studies of the American mink in its natural habitat, North America?
Yes, in the 1940s and 50s, but mainly of terrestrial behaviour. There have been diving studies elsewhere, in Tierra Del Fuego for instance, where mink are diving in the sea, and of feeding in Sweden.

How long did the mink wear collars?
Joanna aimed to collect collars after three weeks, but if missed, they were designed to be readily biogradeable, rather than made of more durable leather.

Where do mink live?
They don’t excavate, but occupy existing holes. Sometimes these are in trees, but mink are particularly fond of rabbit warrens.

Are males and females mutually antagonisic?
Yes, males and females join only to mate. Mink of each sex maintain their own, linear, territories. The males occupy about 5 km, overlapping two of the smaller females’ 3km territories. Males will not tolerate each other. Mink are not social; apart from mothers and kits they do not share.

How related are they to the European mink?
Less so than previously thought; they are of a different genera. Indeed there is no knowledge of hybridisation. European mink used to be found in the Baltic states, Poland, Belarus and Russia south to northern Ukraine. No population is known to have existed in the British Isles.

Has the return of the otters in recent times deterred the mink?
It appears not, though it has affected the mink’s behaviour.

Monday, 5 September 2016

Dormouse Project, 1982-1994 and the first release of captive-bred dormice in the UK

A Talk by Dot Eaton to the Berkshire Mammal Group
3 March 2016

Over thirty years ago Dot was an animal keeper near Loch Lomond, when she formulated an ambition to build a captive-bred stock of British animals and reintroduce them to the countryside, but was warned there would be significant difficulties. Each animal would have to be vet-checked, landowners’ permission would be required, and some animals simply couldn’t be bred in captivity. However, she took heart from Gerald Durrell’s private assistant John Hartley and settled on dormice as her preferred species. At the time there was only one book on the subject, Common Dormouse by Elaine Hurrell, the daughter of Harry Hurrell. Eventually Owen Newman, a BBC cameraman, was recommended to her as someone with relevant expertise; someone who recently had even filmed a dormouse giving birth. It was Owen who trapped her first dormice at a location in Wiltshire, giving Dot three while retaining two for his own use. Dot had, by this time, qualified for a licence and Owen give her other dormice on subsequent occasions.

Dot’s first breeding colony
In 1982 she moved to Chessington Zoo and started breeding her first colony, and when she relocated to Windsor Safari Park in 1988 she moved her dormice with her. She had a small shed, divided into four and fitted with a central red light, but something larger scale was required and Dot designed a new breeding unit. The journal Robin Page visited and wrote a very supportive article in Country Life, helpfully ending with an appeal for funds. A cheque for £2,500 duly arrived from Mrs T. Hesketh of the Valerie White Trust, and the new building was erected. It had eight enclosures divided by Perspex to prevent the transmission of disease. In each enclosure was paced one male and one or two females – 16 animals in all – and Dot filled them with fresh branches twice a week: Hazel, honeysuckle and rosebay willowherb. She had red lights fitted to allow her to observe the dormice from a adjoining corridor and thus improve her understanding of their behaviour and ecology.

Observations of dormice
Their first reaction on Dot entering the enclosure was to freeze stock-still. They weren’t particularly sociable and didn’t feed together. Rather, if the encountered each other, the dominant individual would maintain its place and the other would run away (and surprisingly fast). Consequently Dot realised that food supplies had to be distributed widely throughout the breeding unit. Having said that, several dormice would share a nest box; perhaps three or four together. Sadly she never saw the process of nest building – presumably as they were inside the nest-boxes – but she did see dormice stripping branches in preparation and stuffing soft honeysuckle bark into their mouths before taking it to a box. There are several nest types: two or three-leaf nests made by juveniles; round nests full of bedding as breeding nests; and semi-subterranean grapefruit-sized nests in which to hibernate. The latter are at ground level and built partly into scrapes to achieve as stable a temperature in winter as possible. The adult dormice emerge in May in time to breed. They run and chase each other for three nights before finally mating. Then, if pregnant, the female will retire to a nest after 30 days to give birth. After a further 30 days the juveniles appear. (If not pregnant the chasing resumes after about 10 days, but most litters are early.) When the juveniles emerge it is fascinating to observe their varied personalities and the mistakes they make. They don’t know to freeze and they miss branches when climbing; Dot realised they are very vulnerable in the early days of life. Indeed if the temperature falls to blow 10 oC for several concurrent nights, then – assuming the juveniles are not fully developed – the mother will go torpid and the youngsters will die. As a result there may be second litters to replace the losses. In mid August the adults fatten up to hibernate; the youngsters take longer to prepare for the winter sleep.

The reintroduction team
Dot realised that a number of skills were necessary for success, many of which she personally didn’t have, and so assembled a team of experts to help.
  • Martin Hicks
Ecologist in Hertfordshire
  • Dr John Lewis
Vetinary surgeon
  • Julian Ford-Robinson
Senior Science Master, Haileybury College
  • Prof John Gurnell
Behaviourologist at QMC, London
  • Steve Whitbread
Tracking specialist, Southampton University
  • Dot Eaton
Dormouse breeder

IUNC Guidelines
These govern captive breeding for reintroduction projects worldwide and are founded on several fundamental principles:

  • There should be evidence of former occurrence
  • The causes of previous loss should be understood and a result of human action
  • The factors causing extinction are to have been rectified
  • The proposed habitat should be suitable and of sufficient extent

All of these were met at the proposed site at Haileybury in Hertfordshire, as though the site was small (7 hectares), two substantial hedgerows linked it to extensive woodland nearby.

1992: The Reintroduction
On 18 August the dormice were placed in a cage and observed until 23 September when the hatch was raised. One dormouse ventured out along a branch and returned. Within half an hour the colony had moved into the wild. There were two family groups: a male, two females and two young in one, and one female and five young in the other. One juvenile was radio tracked and was found to have ranged 35m and back. Three others ranged by a similar amount that first month. (Perhaps the rest did too, but only some individuals were monitored.) Five more juvenile males were added the following year, and more the year after.

Further observations
It was apparent that the dormice liked to explore and spent little time on the ground. Their squeaking is much like that of a mouse

1994: Burnham Beeches
In 1994 Windsor Safari Park went into receivership and despite efforts to sell it as a going concern, it was finally sold for development as the new Legoland. Employees, including Dot and her husband, were evicted from their tied cottages. As well as the loss of her home, Dot had 97 animals to care for. Initially the dormice were taken to St Tiggywinkle’s, and then to Burnham Beeches were they and the breeding unit were offered a home by Mark Frater and Helen Reed, the keeper and ecologist there. Indeed, as well as feeding and looking after the dormice, Mark and Helen even built a second breeding unit. Eventually Dot arranged for a contract to assign ownership jointly with the Corporation of London (owner of Burnham Beeches). With others expressing an interest in the project, a Common Dormouse Captive Breeders’ Group was formed and continues to function to this day. Since 2000 the reintroduction programme has been administered by the People’s Trust for Endangered Species, which has now run as many as 25 such projects (involving partners such as London and Paignton zoos). Meanwhile Dot has been invited to speak at international conferences in Denmark and the USA, though without her own facilities, she is no longer been active in breeding dormice.

To which Martin Hicks, present in the audience, contributed.

Taxonomy – dormice are a group of their own, with two species in the UK: Common and Edible.

Breeding – litters of 2-6 juveniles. They remain in family groups for a while, both parents looking after the youngsters. Pairings are temporary, however, as dormice are quite promiscuous.

Physical characteristics – include a semi-prehensile tail and forward facing eyes

Behaviour – they are arboreal and nocturnal, but particularly active at dusk and dawn. They hibernate throughout the long winter months, though in Mediterranean countries the higher temperatures require much less hibernation. When torpid or hibernating, they are vulnerable to ground predators, such as badgers and wild boar, though dense vegetation protects them from the attention of owls. Their food supply, however, is adversely affected by the presence of the more vigorous grey squirrel.

Habitat – not just coppiced hazel, although that is most characteristic and 2-3 year old coppice is ideal, they will even be found at the edge of pine forests and where there is dense vegetation. However, it is habitat loss that has been the biggest cause of their decline; the loss of managed woods with lots of new growth, and the ripping out of hedges has isolated and exposed them. There has been massive change in the British countryside over the past century.
Edwin A.R. Trout
Berkshire Mammal Group

Scottish Wildcats And Mammal Conservation in Scotland

A Berkshsire Mammal Group Talk by:

Alicia Leow-Dyke, 3 December 2015

Opening the evening, Vice President of BMG, Melanie Orros, introduced Alicia as a friend from their MSc course at Imperial College some years ago and who has since spent time as a staff naturalist at the Aigas Field Centre in the Highlands on beaver demonstration and wildcat breeding projects – even appearing on television in Autumn Watch. Alicia went on to explain that the centre was built as a hunting lodge in the Victorian period and after 1947 was used as a retirement home. Then in the 1970s it was bought as a facility to encourage environmental education. Aigas is located near Inverness, , with trees surrounding the house, a loch nearby and extensive tracts of moorland beyond, amounting to 800 acres. Her time there gave her the opportunity to be involved with projects to conserve several species that are characteristic of the Highlands.

Scottish Wildcats

Alicia started with the Scottish Wildcat, or Felis silvestris grampia, which, since the extinction of the lynx, is the only naturally occurring feline in the UK. Some regard it a sub-species of the European Wildcat; others the local manifestation of a species common throughout the continent. There are related species in Africa, Middle East and Asia too. Wildcats were once found throughout Scotland and the rest if the UK, and not just in the Highlands.

Slightly larger than the domestic cat, males are around 8 kg; females, 3-5 kg. Their diet is varied, consisting of mice, rats, voles – even pheasants – but with a preponderance of rabbits.

The females have two estrus cycles, each lasting 8 or 9 days in Dec-Feb and May-July, though a second generally only if the first cycle has been unproductive. Gestation lasts around 60-68 days and most kittens are born in April or May. Litters vary between one and three kittens, but more often or not are two. They live for 13 / 14 years, though the oldest in captivity is 21.

They face a number of largely man-made threats. Loss of habitat is significant, particularly with the growth of plantations in the twentieth century; exotic species and regular planting creates a sterile monoculture, large, dead and dark, with few rocks and roots in which to den. They have been hunted in the past, as their soft fur was highly prized, and like other wildlife, they suffer from traffic accidents. Natural predators (particularly of kittens) include eagles and foxes, but the most characteristic threat is their propensity to hybridise.

The domestic cat derives from the North African wildcat, domesticated 8,000 to 10,000 years ago at a time coincident with the rise of agriculture. They have since spread with human migration. Differentiation between the domestic and wildcat is difficult. Wildcat skulls will stand on end without falling over. The intestine of the domestic cat is vastly longer than that of the wildcat – maybe three or four times the length. And there are genetic differences. But possibly easier are the distinctive markings of their pelts. Wildcat stripes tend to be much finer than a hybrid or domestic tabby, and the dorsal line in wildcats stops at the base of the tail.

Today there are perhaps 400 to 1000 wildcats in the wild, possibly as few as 100 reasonably pure bred cats, and they constitute one of the rarest mammals in the UK

Consequently a captive breeding programme was established at Aigas in 2011, and Alicia was its manager for four years. The first pair of cats arrived in March 2011, from a scientist’s private breeding scheme in Perthshire, and the second came a year later. A pair of kittens was born in 2012 and another two in 2013. (Incidentally, kittens’ eyes are blue at first, turning yellowy green after a few weeks.) The long-term aim, yet to be realised, is to release them in the wild.

In 2013 a Wildcat Group was established with the support of Scottish Natural Heritage and a six-year action plan was launched. 30-40 organisations are involved in various capacities: surveying habitat, identifying and preparing release sites, monitoring populations, neutering feral cats, promoting responsible cat ownership, and breeding wildcats.

One of the tasks is genetic testing. This can be on a variety of samples – hair, faeces or blood – of which the latter is best. Taking a leaf out of the Spanish programme for restoring the Iberian Lynx, which is some way in advance of the wildcat programme, the test is fulfilled by placing ticks in the cats’ dens which, when sated with blood, drop off their host and constitute the sample! Many of the wildcats tested have proved to 60-70% pure, with a proportion of domestic cat. Finding 100% wildcats is looking increasingly unlikely. What to do about hybridisation is a divisive issue, however. Some conservationists are purists, other accept a degree of hybridisation as healthy and a reflection of today’s reality. Supplementing the Scottish population with European Wildcats from elsewhere, say Turkey or the Levant, is seen as ‘Plan C’, because maintaining a distinctly Scottish identity is thought important. However, suitable European populations are being assessed for possible future integration.

At Aigas the breeding facilities allow for enrichment activity, with aerial walkways, swings etc, to mimic conditions in the wild. The food is natural – rabbits, venison – though males and females are allowed to run together (which they wouldn’t normally, the males being solitary) to maximise the opportunity for breeding. They even have “starve days” to reflect the vagaries of hunting. The kittens stay with their parents for a year, then the males and females are separated to avoid in-breeding


The talk was suspended briefly for an impromptu discussion, the answer to some of the questions being incorporated, where applicable, in the account above.

Can you handle them – are they fierce?
You don’t handle them except for testing and separation, as they will spit, jump and use their claws freely. You need thick gloves and the rapid administration of anaesthetic!

Is it possible to establish for how long wildcats have hybridized with domestic cats?
Yes, over recent generations. A longer-term test is being developed in Switzerland.

Does hybridization make a difference to behaviour?
With 60-70% wildcat genes, there seems to be little difference between pure and hybrid in terms of either fierceness or fertility.

Do they purr?
No. They wail, caterwaul and hiss, and the kittens squeak.

Their characteristically flattened ears suggest aggression. Do they prick up their ears?
Dificult to say as they are usually aggressive in the presence of humans.

Have they been vaccinated at Aigas?
No, not yet

Is there any radio-tagging to establish range or behavioural patterns?
No, as the cats have not yet been released, but camera traps have given an indication of the movement of wildcats. The full range is not established and promises to be difficult, as wildcats keep on the move, denning overnight and moving on (except when with kittens).

Are they arboreal?
They do climb trees, and like to perch high up on a prominent branch, but they don’t climb to the tops and don’t sleep in trees

Red Squirrels

Reddish fur in summer and duller brown in winter, with characteristic ear tufts, the Red Squirrel lives in coniferous and broadleaved woodland, occupying 3-7 hectares or so. Its life span is 5-6 years. The squirrel has a varied diet of cones, seeds, nuts and berries. Nibbled pinecones are a telltale sign, with an uneaten ‘handle’ where they hold the cone. They stash food in Autumn, but their memory isn’t good and they often forget where food is stored.

Red Squirrels can be found throughout Europe, Siberia (except in the Arctic north), Manchuria and Japan. They have been introduced to Georgia in the Caucasus. In the UK, however, they have retreated in the face of expansion by the incoming Grey Squirrel. In the 1940s they were all over the country; Greys were only in the South East and southern Midlands. Now Reds are found mostly in Scotland – the Highlands, Southern Uplands, Cheviots – along with Anglesey, Brownsea Island and the Isle of Wight. There are 120,000 Reds in Scotland, with 15,000 in England (of which 60% in Northumberland.)

It is a misconception that the Grey attacks the Red; the problem is more to do with food resource competition and especially the spread of squirrel pox, of which the Grey is a carrier and to which the Red is susceptible. However, Reds do better in pine forests, as the Greys are heavier and less able to make use of the flimsier branches of coniferous trees. There is also an active policy of controlling Greys in Scotland.

Pine Martens

Linked to the above is the recovery of Pine Martens in Scotland (and to a lesser extent, the rest of the UK. For some they amount to a conservation tool for controlling Grey Squirrels. The population recently was 3,500 in the UK and rising, with 3,000 or so in Scotland. They are natural in the Highlands and, since 1990, are reappearing in the borders with the odd one popping up in the Cheviot Hills and North Yorkshire. In Wales the Vincent Wildlife Trust has been active with the reintroduction of 20 animals and there has now been a sighting in Shropshire. They also appear naturally in Ireland.

Like Red Squirrels, they have two moults and are redder in summer. Significantly, each animal has specific markings on its distinctively pale bid, making identification of individuals possible.

Pine Martens eat berries, nuts, mammals, birds, eggs – even peanuts and jam! They opportunistic and will enter buildings for food and shelter. Alicia showed pictures of one such creature that had taken up residence in a hide at Aigas in order to forage on peanuts. Naturally Pine Martens live in rocks, caves, roots and up trees, though now make use of next boxes devised by the Vincent Wildlife Trust.


There are thought to be 250,000 in Britain, of which 25,000 are in Scotland, but their behaviour is different in the north due to the marginal habitat and the associated paucity of food. They tend to live in smaller groups: 6 to a sett, rather than up to 25 in some parts of England. At Aigas there are usually 3 or 4 per sett, with several setts in the area. It is difficult to identify individuals, except by the battle scars borne by some of males. Despite the lower density of traffic in Scotland, there are appears to be no respite for the badger, which all too often ends up as roadkill. However, with no Bovine TB in Scotland, farmers offer much less of a threat to badgers.


There have been various projects to reintroduce beavers to Scotland: Knapdale and the River Tay, as well as Aigas in 2006.

The herbivorous Castor fiber – which, contrary to widespread assumption, doesn’t eat fish! – is similar to the smaller North American beaver and can be found across Eurasia from Britain to Mongolia. In Europe it survived persecution mainly in Scandinavia. Otherwise it was hunted to extinction – by C14th in England and C16th in Scotland – for their fur and medicinal qualities ( salicylic acid). By 1900 only 2,000 or so were left in Europe, while now there are 700,000! Indeed there are so many that in some jurisdictions – Lithuania and Bavaria, for instance – hunting in October is permitted to control numbers.

The first reintroduction to Scotland was at Knapdale, were three or four families were brought in from Norway. In 2010/11 a separate group of beavers were found in the wild on the River Tay, numbering as many as 150-200 individuals at present. It isn’t known if they were illegally released, or escaped, but there presence in an agricultural district enables useful comparison with the forested habitat of Knapdale. A decision by the Scottish government is due in 2015 on whether to allow a more widespread reintroduction, though it looks increasingly likely to be deferred to next year. Without human intervention colonisation would be slow.

In 2015 the beaver was reintroduced to England too, with the discovery of a pair on the River Otter in Devon (now with an additional three youngsters). An initial decision to remove them as ‘non-native’ was rescinded in response to public opinion, on the condition they were tested for atapeworm to which beavers are susceptible. They were clear, so Defra permitted their continued presence on the Otter for five years’ monitoring by the Devon Wildlife Trust. There are plans for a reintroduction to Wales, too, with sites prepared for future occupation.


How far would beavers spread?
They are quite territorial and it depends on population pressure. If the group is large, the 2-3 year olds will disperse some distances, but if the group is small, with sufficient habitat for the resources it needs, then the juveniles will remain close by. So in the five years permitted in Devon they won’t go far.

How do they interact with otters?
They generally get along. The main risk is the vulnerability of vole-sized beaver kits in May/June, as if an otter enters the lodge he/she will kill them. Usually, however, the otter is curious, teasing the beaver, which in turn simply ignores the attention.


Opening up for discussion at the end of the talk, questions returned to the Scottish Wildcat. Would there be conflict with the lynx should the latter be reintroduced? It would be a cause for concern, but largely for pressure on food resources (rabbits, especially), rather than on the risk of predation. Other questions related to the preparation for future release. Is there a risk of habituation? Yes, so although the adults are for breeding and will not be released, the kittens are left alone as much as possible. However, the lengths of disguise are not resorted to with wildcats as with the bustard chicks in Somerset; wildcats would not be fooled by a stripey onesie!

Edwin A.R. Trout
Berkshire Mammal Group