Hard to imagine that the last time I spent time in Sumatra was in 1996 back in the La Selva Expeditions chapter of my life.  And the time before that was in 1984 in the early days of my backpacking sagas….  So much has changed – especially me!  I would say that the most notable change was the great expanses of oil palm that now engulfs pretty much all of Sumatra and Indonesia in general.  Such a tragic change.  Equally tragic maybe I am hitting end days for these sorts of treks – getting old sucks!  Haha. 

I’d always wanted to try for some of the Sumatran langurs, which are some of the hardest to see of all of the so-called “Leaf Monkey”(Trachypithecus & Presbytis spp.) complex, with the exception of Thomas’s which are very easy in Bukit Lawang and other locations in and near Gunung Leuser.  This may very well be true with the others too but honestly there are not enough known locations that make them easier to target.

After reading Mark Spence’s trip report (linked here) on Tapanuli, along with a long time urge to see at least the spectacular Thomas’s Langur, I decided to form a plan to visit Sumatra once again to attempt the success Mark had in seeing the legendary Tapanuli Orangutan.  And combine that with attempting to nail a couple new Langur lifers and some better pictures of the Sumatran Orangutan, which I had encountered in 1984 albeit completely habituated and tame at Gunung Leuser.

This time I was accompanied by my good friend, Ben Weil, from Bangkok.  Ben and I have been buds for about four years – basically since Covid.  Ben is a keen and very skilled birder who is interested in all forms of wildlife and is a great guy to go wildlifing and have a beer with!  And his keen spotting skills and knowledge of the avian and insect fauna is a welcome addition to any expedition. 

(Side note: Somehow Ben and another good friend, Jan-Peter Kelder, coerced me over to the dark side of birding and bird photography during Covid which was a nice activity that literally kept me outdoors during covid as much as possible.  So much so that somehow, I amassed images of well over 500 species of Thai birds during the Covid years and post.  (Link to gallery here))

Tapanuli

Our first destination was the Tapanuli, specifically the Sitandiang Forest, Batang Toru which is about three hours and a bit from Sibolga.  To get there you basically need to fly into Medan and then take a local flight to Sibolga, which is less than an hour.  Currently there are two flights a day from Medan.  From the Sibolga airport (which is not very near the town of Sibolga at all), we drove to Padang Sidempuan to pick up Decky, our expedition leader.  From there we continued on to Sipirok.  This is really not something that can be done on one’s own and the only game in town is Decky’s company, Tapanuli Trekking Tour.

Decky is easy to contact on Whatsap, but I think checking out his Facebook page is the best way to start. (linked here).  Decky can arrange all of the logistics for as many days as you want to spend in the forest.  But this trip is not for the faint of heart – more later on this.

Normally the drive would be another hour or so from Padang Sidempuan, which would have made the total travel time from the Sibolga Airport to be about three hours, but we had the fantastic luck to run into a sizable demonstration!  This cost us at least a couple of hours and we were not even sure we’d get past the demonstration at all – they seemed very entrenched to say the least, completely blocking all traffic in both directions.  Now this was one of those situations that was hard to be angry about, or even irritated over.  These villagers were demonstrating against a Chinese paper company who had somehow gotten (somehow, yah right – we all know what really happened - $$$$) a permit to level massive tracts of the Tapanuli rainforest for pulp….  With this cause, I pretty much felt more like joining the demonstration rather than being irritated by it, even though it meant we were definitely going to start our journey in to the forest in the dead of night.  Anyway, I sincerely hope their demonstration helped the cause, which is certainly just one.

We were trying to bypass the demonstration by hiring local bikes to take us past the mob as the place where the trail starts was supposedly about 20 minutes further…. (although it was much further than that!)  But just as we were about to load up the motorcycles with all of our gear, the road magically opened up! Thank goodness as had we actually tried to get up to the trailhead by motorcycle it would have been a nightmare ride to say the least. 

Ok so about 8 or 9PM we finally made it to the trailhead area.  Here we met the rest of the team with Mr Hasibuan as our patriarch and the official ranger for the trek.  Now the way I understand it, this protected area is a community effort, and all of the conservation duties are performed by community members, such as Mr Hasibuan.  All told, we had a crew of seven strong men for this trip.  All of whom were stellar and incredibly kind and helpful, especially to me. 

After we were all assembled, we made our way down the trail.  Normally for normal people, this trip to base camp takes an hour and a bit.  I, however, took nearly FOUR hours!  This is where I found out that I have something pretty seriously wrong.  Of course, the trail was very steep and muddy and slippery at several points, but I experienced vertigo or some sort of other dizziness caused perhaps by low blood pressure that I could not keep my balance at all – it was truly a nightmare for me.  Uphill was a challenge for me, but the downhills were insane – I mean I was truly freaking.  Thank goodness we had as many helpers as we did because there were moments during this trip, I needed them for sure!

So, by around midnight, we made it to Base Camp (known as “First Base Camp” I believe). (Link to map for approximate location of Base Camp) This was quite a set up.  Basically, the beds are comprised of young freshly cut wood spread the width of 50 lb rice bags with the rice bags being your actual bed.  I opted for a tent as I know there was no way I could fit in such an apparatus.  Ben opted to sleep there and did fine.  But my advice for future travellers is to bring your own gear to a degree – sleeping bags for sure as the ones in the camp are not adequate - too small and it does actually get pretty cold up there.  The cuisine is basic so I would advise making special requests ahead of time.  Decky did try to vary things for us, which was nice, so we did fine.  Again, the crew is epic – very helpful and responsive.

Search for the Tapanuli Pongo

Prior to our arrival Decky had a crew in the forest finding and tracking a male Orangutan.  They followed it daily and had it spotted for some four days, including the day of our arrival.  It was staying very close to Base Camp in fact.  Our first morning, we woke to a cacophony of Hylobatidae song – from all directions!  First were the Siamang with an awesome and aggressive chorus. I could confidently say we had at least SIX Siamang groups within earshot of camp. Compare that with the gentle singing of the Sumatran White-handed Gibbons which were equally numerous. Honestly, I am not sure I’ve ever been in a forest so densely populated with Hylobatids all singing at once in all directions – so cool. (link to two videos sharing this chorus).  We also heard what I am sure were the Sumatran subspecies of Agile Gibbons.  On top of that, we heard the warning “coughs” of the Sumatran Black Langur, although I cannot claim them as lifers as I never saw a single one! 

Just as were going to get ready for a morning trek deeper in to try for that male, mother nature decided to give us an entire morning deluge of rain!  Some four hours of pretty intense down pour kept us in camp – thankfully we had not started yet as it would have been a brutal downpour to be stuck in in the middle of the forest in.  Mother nature basically made sure we all got a few more hours of rest after that very late-night arrival to Base Camp. 

Trekking time!  I was hoping to feel better but if anything, I was off even more – feeling light-headed very dizzy at the slightest movement – having a hard time just standing up…. this sucked big time!  I made sure that the team gave Ben a full experience though - no reason for him to compromise his experience due to my pathetic condition.    

We immediately found very fresh sign of the male Orangutan about 100m from Base Camp – loads of half-eaten drupes on the ground showing for sure that a very recent Orangutan had been splurging, no doubt the one that Decky’s crew had been following for us.  After that immediate rush of impending “target soon-to-be achieved” we slowly began to realize that that he had moved on during the deluge of rain…. We never found him.  Such is wildlife-watching – even what seems like a sure thing ain’t a sure thing!

After some more trekking and more enjoyment of the awesome forest and sounds of the Sumatran Lar Gibbons, we made our way back to Base Camp, where I was literally calling it “done”.  I really was resigning myself to getting skunked – I just didn’t have it in me to continue.  Ben on the other hand was fine and went on his own trek with the team.  As I was recovering in my tent, I heard the back and forth on the walky-talkies and then came the question I had hoped for: “Coke, they have an Orangutan – do you want to try to go and see?”  My body said no but my brain said, “hell yes”. 

I asked how far it was and the answer came back as “about 500 meters” …  Having spent several trips in Indonesia, I knew to multiply any estimation on distance (or time for that matter) by two or three.  But it didn’t matter, I was going for it!  I called Ben on the radio and asked for a western estimation of distance and difficulty, and I was clear that the initial message was off a bit but not by much!  It took me about 20 minutes or so to get to the spot where I saw Ben and Hasibuan looking off into the high canopy.  I immediately looked in their direction to see TWO Tapanuli Orangutan!  Mom and a baby.  I got a snap view of them for a millisecond before they immediately moved out of view!  Of course they did.  Of course I needed better views.

Now these individuals were timid and clearly not used to people.  They were constantly moving to and fro only allowing glimpses of orange behind foliage.  It soon became clear that the initial two individuals were in fact three as I saw mom and baby head in one direction and what appeared to be a sub-adult female head in the other!  I wonder what was the cue for them to do this – how did they communicate this maneuver to each other?

Finally, after and some time I got a slightly better view lasted long enough for a few crappy images.  That’s all I was allowed, and I am damn happy with that!  My dizziness made it very difficult to focus and follow them as they traversed the canopy.    But our main target was achieved!  Such a sweet feeling.  And with some crappy images for proof!  My other target, the Sumatran Black Langur, will simply be a pipedream I suppose.  Who knows, maybe I will return some day.

As mission was accomplished, all I had to do now was stress about how the hell I was going to get out of this valley.  It was tough to sleep that night as I was pre-occupied with this thought.  I did manage a bit until I had what I thought was the strangest dream – in the Tapanuli jungle, all of the sudden hearing total redneck American country music blasting – “I am a country boy…. I have a 4-wheel drive….”  I shook my head and realized that it was actually coming from camp!  Hahaha!  Decky evidently loves good-ol’ redneck music! Especially Alan Jackson tunes….Go figure.

Well, the trip up for me was maybe a bit worse than the first night.  But with some intense help from Decky and his awesome team, I eventually made it out!  Alive!!!  Now before you think about not going due to this hike, don’t let my experience dissuade you.  I was in a bad way before the hike for sure.  I would say that a normal trekker would rate this as a medium trek – not anything unmanageable if you are in a normal condition and reasonably fit.  So, no need to worry about it really.  Now with that said, depending on where you encounter the Pongo, you may find that the trekking can become extreme in a heartbeat, if the critter decides to head downslope or upslope along the steep hills in all directions….Hope for the level area!

 More Pics from Tapanuli

A Bit of Natural History of the Tapanuli Orangutan

Tapanuli Orangutan (Pongo tapanuliensis)!  Was designated as a valid species in 2017 making it the newest Great Ape species.  Originally a subspecies of Pongo abelii it finally gained recognition as a legit species based on DNA studies.  The giant Mount Toba evidently provided the geographic barrier that created the conditions its speciation from the other two species.  And I am not sure how the Toba Super Volcano eruption some 75000 year ago impacted this – would love to know more if you know more! And owing to this geographic barrier, the population remained isolated for about 674,000 years, plenty of time for significant genetic drift and phenotypic change. 

Bukit Lawang Gunung Leuser National Park

Quick flight back to Medan where were met by our driver for the three plus hour drive to Bukit Lawang for the second half of our journey in Sumatra.  Here we met our expert guides, Julia Bayu and his brother, Aji Purnomo – two fantastic experts who were born and raised in Bukit Lawang and know it perhaps better than anyone.  (Contact them here) Initially we stayed at the Batu Kapal Lodge, a very nice homestay located 15 minutes down a “thrilling” motorcycle path in a very remote part of Bukit Lawang in an area surrounded by various fruit plantations (mainly durian) and some secondary and tertiary forests.  The disturbed nature of the area did not mean it was devoid of wildlife at all – it was still very decent for birding and many mammals, including wild Sumatran Orangutan which are seen there regularly.

My targets here were simple – Sumatran Orangutan (Pongo abelii) and Thomas’s Langur (Presbytis thomasi), both of which were pretty easily seen within a few hundred meters of the Bukit Lawang Eco Lodge on day one.  A lovely mom and baby were raiding a local mangosteen orchard and gave us amazing views for quite a while.  Bayu initially found the pair and had private viewing but soon a group of people appeared, and before too long dozens of people showed up.  Bukit Lawang is very overcrowded with tourists this time of year and one can expect a cue of over one hundred tourists for an easy to see Orangutan on the main trail.  It was awesome to see this semi-wild female and here wild-born baby for as long as we did.

So, mom was released in to the wild in 2015 after spending one year in the rehabilitation center having been displaced by habitat loss and being orphaned.  So, calling her a “wild Orangutan” would not be inaccurate at all but ‘habituated’ is a better term, I think.  Truly wild ones here would most likely require deep multi-day treks to the interior.  And getting good views of them would be very tricky indeed as they would be as skittish as our Tapanuli trio. And other than seeing the more nervous behavior one would really never know for sure if what they were seeing was a truly wild one or simply a nervous rehabilitated released individual.  For me I am totally happy seeing these habituated individuals.  It’s really no different than the gorilla viewing – all the ones you will see “in the wild” are wild and habituated as are many other “wild” animals on peoples’ species lists. 😉

After three nights at Batu Kapal Lodge, we opted to move to a new location mainly because of remote location and the dangerous motorcycle ride required to come and go.  The electric power situation is quite dire there as well.  We had power less than half our time there.  But other than that, I can recommend the lodge as a great bargain homestay with absolutely lovely hosts.  The owner is also the owner and operator of Nature For Change , a super non-profit aiming to reforest areas adjacent to the national park that will allow for expansion of canopy corridors for Orangutans to use to their feeding grounds. 

One plus of the Batu Kapal Lodge’s location however is its proximity to buffer-zone disturbed forest which makes birding and squirreling easier.  Not only that, but Orangutans also regularly come by and raid the durian, rambutan and mangosteen plantations.  And week prior to our arrival less than 300 meters from the lodge, there was a SUMATRAN TIGER skulking around!  And earlier this year a Sumatran Tiger actually got a neighbor’s cow!  From what I learned, Sumatran Tigers have been much more commonly spotted in the edges of the park and even venturing into the villages in recent years  Another plus is they make a mean chicken curry!

This day concluded with an amazing feast prepared by Bayu, Aji and crew – absolutely outstanding meal with “jungle curry”, chicken rendang, and more fruit than humanly could be consumed. And the Bukit Lawang theme song serenade!

The next few days was basically more of the same, with recuperation being my main objective.  While our stay at the Batu Kapal Resort was very nice, we ended up switching to the more centrally located Bukit Lawang Ecolodge, which was very nice – the upper deck of their restaurant was a massive bamboo hall that was a great place to while away a tropical afternoon downpour.  Their food was not very good.

Around the Ecolodge and the surrounding areas near Bayu’s and Aji’s guest houses were some significant rock formations on which some 16-18 Sumatran Orangutans were known to nest most of the time.  But considering this time of year was fruiting season, they were quite dispersed and only a couple were spotted there (not by us).  Ben did trek deeper into the national park and had a good day with several species, including Sunda or Southern Pigtailed Macaques, Black & White Giant Squirrels (the color of which is quite unique – like a hybrid blend between the Cream-colored Giant Squirrels and normal Black & White Giants – see Ben’s photo on this page).  He also photographed Sumatran Siamang and Sumatran Lar Gibbons. During our walks we did see quite a few smaller squirrels which included Robinson’s Squirrels (previously Low’s but split on Sumatra & peninsular Malaysia), Slender Squirrels, Least Pygmy Squirrels as well as Plantain and Black-lined Squirrels.  I did catch a reasonable look at a Horsetail Squirrel.

Expedition Sumatra 2024 was an unmitigated success!  Dipping on the Black Sumatran Langur was a bit of a bummer, but Decky does maintain that he has a good location where they can be spotted easily, so I may take him up on this in the future.  We did try one spot near Sipirok that has them from time to time but only got Silvery Langurs. 

Upon returning to BKK, I will be looking into my dizziness issue with hopes that strenuous expeditions are still a possibility for me – still so much to see!  But overall, it was great to spend time in such lovely rainforests with awesome guides, team members and of course, Ben!  His expertise and positivity made our time together absolutely spectacular.  Looking forward to future trips!

 Sumatran Orangutan (Pongo abelii) Bukit Lawang

 Other Primates from Bukit Lawang

 More Odds & Ends from Bukit Lawang

 Mammal Species List

1.      Tapanuli Orangutan (Pongo tapanuliensis)*

2.      Sumatran Orangutan (Pongo abelii)

3.      Thomas’s Langur (Presbytis thomasi)*

4.      Silvery Langur (Trachypithecus cristatus cristatus)

5.      Long-tailed Macaque (Macaca fascicularis fascicularis)*

6.      Sunda Pig-tailed Macaque (Macaca nemestrina)

7.      Sumatran Siamang (Symphalangus syndactylus syndactylus)

8.      Robinson's Squirrel (Sundasciurus robinsoni)*

9.      Slender Squirrel (Sundasciurus tenuis)

10.  Least Pygmy Squirrel (Exilisciurus exilis)

11.  Black & White Giant Squirrel (Ratufa bicolor)

12.  Horse-tailed Squirrel* (Sundasciurus hippurus)*

13.  Plantain Squirrel (Callosciurus notatus)

14.  Greater Mouse-deer (Tragulus napu) (could be Lesser Mouse-deer)

15.  Sumatran Lar or White-handed Gibbon (Hylobates lar vestitus)

16.  Mountain Agile Gibbon (Hylobates agilis agilis) (song only)

17.  Black Sumatran Langur (Presbytis melalophos) (camped above our area – voice only heard)

18.  Sunda Leopard Cat (Prionailurus javanensis) (seen by resort owner near my bungalow)

19.  Horsfield's Fruit Bat (Cynopterus horsfieldii)

20.  Fawn Leaf-nosed Bat (Hipposideros cervinus)

21.  Dusky Leaf-nosed Bat (Hipposideros ater) (waiting for ID confirmation)

 A Bit More….

Sumatra Bird List (Link to detailed eBird trip report) 

• Great Argus

• Rock Pigeon

• Spotted Dove

• Asian Emerald Dove

• Zebra Dove

• Pik-necked Green-Pigeon

• Greater Coucal

• Lesser Coucal

• Raffles's Malkoha

• Chestnut-breasted Malkoha

• Banded Bay Cuckoo

• Plaintive Cuckoo

• Malaysian Hawk-Cuckoo

• Malaysian Eared-Nightjar

• Brown-backed Needletail

• Plume-toed Swiftlet

• Mossy-nest Swiftlet

• House Swift

• Gray-rumped Treeswift

• White-breasted Waterhen

• Red-legged Crake

• Eastern Cattle Egret

• Purple Heron

• Oriental Honey-buzzard

• Crested Serpent-Eagle

• Changeable Hawk-Eagle

• Rufous-bellied Eagle

• Brahminy Kite

• Barred Eagle-Owl

• Brown Boobook

• Scarlet-rumped Trogon

• Red-headed Trogon

• Rhinoceros Hornbill

• Bushy-crested Hornbill

• Wreathed Hornbill

• Banded Kingfisher

• Ruddy Kingfisher

• White-throated Kingfisher

• Collared Kingfisher

• Red-bearded Bee-eater

• Blue-throated Bee-eater

• Sooty Barbet

• Coppersmith Barbet

• Black-eared Barbet

• Red-throated Barbet

• Yellow-crowned Baret

• Black-browed Barbet

• Sunda Pygmy Woodpecker

• Rufous Woodpecker

• Buff-rumped Woodpecker

• Banded Woodpecker

• Blue-rumped Parrot

• Blue-crowned Hanging-Parrot

• Silver-breasted Broadbill

• Black-and-red Broadbill

• Banded Broadbill

• Black-and-yellow Broadbill

• Golden-bellied Gerygone

• Fiery Minivet

• White-bellied Erpornis

• White-breasted Woodswallow

• Black-winged Flycatcher-shrike

• Common Iora

• Green Iora

• Gray-headed Canary-Flycatcher

• Dark-necked Tailorbird

• Ashy Tailorbird

• Rufous-tailed Tailorbird

• Bar-winged Prinia

• Yellow-bellied Prinia

• Pacific Swallow

• Hairy-backed Bulbul

• Buff-vented Bulbul

• Black-headed Bulbul

• Spectacled Bulbul

• Gray-bellied Bulbul

• Olive-winged Bulbul

• Red-eyed Bulbul

• Yellow-vented Bulbul

• Pin-striped Tit-Babbler

• Fluffy-backed Tit-Babbler

• Sunda Scimitar-Babbler

• Short-tailed Babbler

• Blue Whistling-Thrush

• Yellow-vented Flowerpecker

• Orange-bellied Flowerpecker

• Sumatran Flowerpecker

• Scarlet-backed Flowerpecker

• Ruby-cheeked Sunbird

• Plain Sunbird

• Brown-throated Sunbird

• Ornate Sunbird

• Crimson Sunbird

• Little Spiderhunter

• Scaly-breasted Munia

• White-headed Munia

• Eurasian Tree Sparrow

• Paddyfield Pipit