Orangutan Adventures in Tanjung Puting

Today makes the start of Orangutan Foundation UK’s #orangutancaringweek, so over the next 7 days I thought I’d share some info about these wonderful creatures and some picture from my recent wildlife photography trip to see them in their native Borneo.

Along with gorillas, chimpanzees and of course humans, orangutans are part of the taxonomic family of primates known as great apes. There are three species of orangutan - the Bornean orangutan (Pongo pygmaeus), the Sumatran orangutan (Pongo abelii) and the Tapanuli orangutan (Pongo tapanuliensis), which was only identified as a separate species in 2017.

Fossil evidence suggests that during the Pleistocene era, from around 1.8 million years to 11,500 years ago, orangutans lived throughout much of Southeast Asia, from Java in the south, up into Laos and southern China. Today, wild orangutans are found only in the rainforests of Borneo and Sumatra.

The orangutan’s preferred habitat is low-lying peat-swamp forest. Their distribution is influenced by fruit availability and they are rarely found above 500m. One such area, the reserve that I visited, is Tanjung Puting. This sits on a peninsula that juts out into the Java Sea. It is a complex mosaic of diverse lowland habitats – over 3000 km2 of tall tropical rain forest and seasonally inundated peat swamp forest. The tropical heath forest - called “kerangas” in parts of Borneo - is only found on very poor, typically white-sandy soils and is characterized by medium-sized trees. Much of the reserve is impenetrable – boat is the most common form of transport, providing access along the wide Sekonyer river and its smaller blackwater tributaries. Rickety wooden boardwalks allow access into the rainforest itself.

The Tanjung Puting reserve is home to a host of species including proboscis monkey, clouded leopards, civets, sun bears; over 230 species of birds including hornbills, kingfisher and white egrets; crocodiles, snakes, lizards and frogs. The area is a hothouse of biodiversity, with diverse habitat zones providing a variety of microhabitats that shelter slightly different fauna and flora.

However, the iconic orangutans are undoubtably the best known species in the area. Field studies of orangutans were pioneered by primatologist Birutė Galdikas in the early 1970s, who established a research station in Tanjung Puting called Camp Leakey. This was named after the legendary paleo-anthropologist, Louis Leakey, who was both mentor and an inspiration to Dr Galdikas as well as Drs Jane Goodall and Dian Fossey, who studied chimpanzees and gorillas respectively. I became slightly obsessed with Leakey’s work on human evolution in my younger years and it was humbling to visit this historic site, which has been the cornerstone of primatology and ecological research for decades.

Over the next week, I’ll share more about orangutans and my experiences in Borneo.
To learn more about orangutans, visit
https://www.orangutan.org.uk/orangutans

#orangutans #redape

Orangutan Life Stages

On this second day of #orangutancaringweek I’ll explain more about the life stages of orangutans.

Orangutans are the largest arboreal animals in the world and spend over 95% of their time in the trees. They are also among the most sexually dimorphic of primates with males much larger than females. Fully developed adult males can weigh up to 21 stone, while adult females weigh less than half that weight. Adult male orangutans can reach a height of five feet and can have eight foot arm spans. Whilst their long arms and legs mean they can move easily through the tree canopy, their weight can result in branch breakages. Although smaller, younger orangutans move almost silently through the forest, the same cannot be said for large males!

Males can attain sexual maturity in their teens, but may not attain full size until they are in their twenties. On maturity, males develop large cheek pads called flanges and also large throat sacs. These are a sign of dominance and are found attractive by female orangutans. The presence of a dominant cheek-padded male within the range of younger adult males may inhibit their development.

Females become sexually mature when fully grown, although they will not have their first offspring until 15 to 16 years of age in the wild. The female’s menstrual cycle is similar to our own, occurring every 29 to 32 days with menstruation lasting three to four days. After successful mating, the female is pregnant for approximately eight and a half months before giving birth.

Usually a single offspring is born, weighing about 3½ pounds. Orangutan babies are completely dependent on their mother, and youngsters stay close to their mother until they reach adolescence, with orangutans having the longest “infancy” of the great apes. The bond between a mother and their infant is very strong.

In the wild, females will not mate and give birth again until their offspring is independent. At Tanjung Putting, where supplementary feeding is given, females are often seen with two youngsters – a young baby and an adolescent that is not yet independent.

Almost from birth, orangutans have a very strong grip, which is necessary for the youngster to hang on to their mother as they move through the tree canopy. Even at the relative safety of the feeding stations, older youngsters often keep at least one limb firmly gripped onto their mothers fur, their proximity reassuring and offering them safety and a quick escape from other adults, should this be necessary

To learn more about orangutans, visit
https://www.orangutan.org.uk/orangutans

#orangutans #redape

Small Mammal Trapping

Small mammal trapping is one of my favorite conservation science activities. There is the excitement of going on a 'treasure hunt' to find the hidden traps and see if they have been tripped, the anticipation of finding out what is inside, and the joy of getting young people involved and seeing their faces and reactions in getting close to nature in a way many of them never have before.

Yesterday I helped out at a trapping session organised by the Yorkshire Mammal Group and Wharfedale Naturalists at the Ben Rhydding Gravel Pits local nature reserve near Ilkley. It was a busy session, with volunteers from both groups eager to see the results of the overnight trap, and a group of scouts also came along to take part.

The results of the survey were good and we found four species on the site, in good numbers. These were wood mouse (bottom photograph), bank vole (top photograph), field vole and common shrew. There was also evidence of rabbits and fox on the site.

It was nice to take time afterwards to catch up with the group over a spot of lunch in town.

The EU Migrant Crisis through the Eyes of a Wolf

Last year I was tasked with writing a journalistic piece for university, on a current affairs/environmental issue. In the current political climate and with the potential for walls along the US/Mexico border as well as across eastern Europe, it seems appropriate to post this.

The EU Migrant Crisis through the Eyes of a Wolf

Image Source: National Park Explorers © Timm & Theresa Martin

Across Europe, border fencing is being erected to control the flow of immigrants and maintain security.  But as well as violating the Shengen Agreement by restricting the free movement of people, such fences could threaten the recovery and survival of large predators such as the Grey Wolf.

Since 2015, an increasing number of migrants have made their way from conflict zones in the Middle East and Africa to Europe, with 1.2 million people seeking asylum last year alone.

Most are fleeing war and persecution, whilst others are economic migrants seeking work and a better standard of living. One of the main routes into the EU is the Western Balkan Route, which runs from Greece through Macedonia and Serbia to Hungary and Croatia.

To prevent migrants entering the country illegally, Hungary has constructed a fence along its borders with Serbia and Croatia, forcing migrants to use official checkpoints and claim asylum in line with international law. In Europe, there are now more physical barriers along national borders than during the Cold War. Four metres high and constructed of wire mesh and razor wire, there are concerns that these new fences could impact on wildlife as well as human migration.

Europe has four large predators – wolf, lynx, brown bear and wolverine. Persecuted in past centuries, the numbers of these large carnivores are slowly starting to recover with conservation effort and habitat protection in recent years.  The European Grey Wolf (Canis lupus) is recovering in ten isolated populations, some separated by over 500km. Wolves need space - typically ranging 30km per day to hunt and holding territories of around 250 square kilometres – and are unrestricted by our political borders.

For the first time in over 130 years, scientists have evidence of the long distance dispersal of European wolves. A young male wolf named Slavc was tracked on his thousand kilometre journey from the Balkans to the Italian Alps, crossing several international borders before settling and successfully mating. Such movement of individuals between meta-populations is important as gene flow between the groups will benefit the species overall.

But the route taken by Slavc is the same as that taken by many human migrants. Conservationists fear that fences erected to prevent illegal immigrants entering Europe will also have an adverse impact on animal migration and dispersal, and could threaten the survival of our iconic large predators.

In a letter to Nature, ecological expert Dr John Linnell of the Norwegian Institute for Nature Research expressed his concerns. He considers that migrant fences may kill animals by entangling them in razor wire, leading to the continued isolation of populations and jeopardising the hard work of conservation agencies to reconnect species. He believes the fences may violate the EU Habitats Directive, and should be redesigned or removed at the earliest opportunity. 

Shocking images have emerged of large animals such as deer becoming entrapped in fences and dying.  But is there any evidence that wolves will be harmed? 

The Hungarian fence runs along just 20% of the border, with the remainder formed by the river Danube. Slavc himself was recorded traversing rivers over 200m wide and successfully negotiating busy motorways and railways, so wolves seem adept at finding a route through man-made obstacles as well as natural barriers.

It is an unfortunately by-product that in trying to regain control of their countries borders, governments are impacting international conservation efforts. Whilst there appears to be no evidence that wolves are being directly harmed by migrant fencing, erecting them may affect the free movement of wolves, threatening the long-term sustainability of wild populations.

Holly Leaf Miner - Phytomyza ilicis

This week I have been collecting some data for the Agromyzidae recording scheme, run by a member of the Yorkshire Naturalists Union that I am becoming more involved with. As it is close to Christmas, the group put out a request for records of the holly leaf mining fly, Phytomyza ilicis.   This is one of few insects that can use tough holly leaves as a food source.

Females lays their eggs in the holly leaf in early Spring when leaves tend to be younger and softer. Larvae emerge from the eggs and tunnel along the leaf veins, creating a "mine". After a period of feeding, the larva turns into a pupa, then later an adult fly emerges from the pupa and leaf mine via a small hole, less than a millimetre in diameter, on the leaf surface.

The larva may not make it to the adulthood as it may be parasitised by the eggs of a wasp – which devour it - or it may be eaten by by a blue tit. If this happens, there may be evidence that the leaf mine has been pecked at/ripped open and the insect removed.

The holly leaf miner is common throughout Europe but appears under-recorded, so hopefully my efforts will help contribute some useful data.

I went for several walks around my neighbourhood and found signs of the leaf miner on many of the trees/bushes. They did seem more prevalent on the older, more mature holly trees. Young bushes or those that had been trimmed (eg. within hedgerows) seemed to be less affected by Phytomyza ilicis.

Sightings can be reported using iRecord (please submit a photograph and your location).