Explorations of an Ecologist: Borneo 2018: Part 6 (Kinabatangan River)

Part 1: Fly to Borneo, Kota Kinabalu (September 30 - October 2, 2018)
Part 2: Kota Kinabalu to Mount Kinabalu (October 3, 2018)
Part 3: Full day at Mount Kinabalu (October 4, 2018)
Part 4: Mount Kinabalu to Sepilok (October 5, 2018)
Part 5: Sepilok (October 6, 2018)
Part 6: Kinabatangan River (October 6-7, 2018)
Part 7: Kinabatangan River, Gomantong Caves (October 7-8, 2018)
Part 8: Tabin Wildlife Reserve (October 8-9, 2018)
Part 9: Tabin Wildlife Reserve (October 9-10, 2018)
Part 10: Danum Valley (October 11-12, 2018)
Part 11: Danum Valley (October 13-14, 2018)

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October 6, 2018 (continued)

The Borneo Nature Lodge is one of several eco-lodges catering to tourists along the mighty Kinabatangan River. While much of the surrounding land has been converted to oil palm and nipa palm plantation, the Kinabtangan Wildlife Sanctuary covers a swath of land immediately adjacent to the river. It creates the illusion that one is surrounded by a vast tropical lowland forest when really in some areas the sanctuary ends only a few kilometers from the river, or is only present on one side of the river. However, the protected riverine forest is lush, diverse and beautiful. Traveling by boat down one of the tributaries invokes memories of the Jungle Book due to the impressive trees overhanging the river, hornbills cruising past and family groups of primates in the trees.

Menanggol tributary, Sabah, Malaysia

The first group of Proboscis Monkeys elicited oohs and aahs from everyone present. Proboscis Monkeys are one of several species of "leaf monkeys" in Borneo that have specialized gut flora to assist with digesting large quantities of leaves.

Proboscis Monkey - Kinabatangan River, Sabah, Malaysia

As afternoon turned to evening we watched the antics of the females and young males. The alpha male who ran this harem sat on his own off to the side, keeping an eye out for usurpers.

Proboscis Monkey - Kinabatangan River, Sabah, Malaysia

A nearby group of bachelor male Proboscis Monkeys were resting in some nearby trees. Apparently one of the males came a little too close, provoking an aggressive response from the alpha.

Proboscis Monkey - Kinabatangan River, Sabah, Malaysia

exploring the Kinatangan River, Sabah, Malaysia

October 7, 2019

The mist slowly rose off the surface of the river as the early morning sun crested the tall riparian trees. We enjoyed a cup of coffee with some banana fritters and set off in two boats upriver.

Oriental Darter - Kinabatangan River, Sabah, Malaysia

One of our first great sightings was unfortunately very distant and not seen by everyone - a distant pair of Endangered Storm's Storks that disappeared behind some trees across the river from the docks. Our first Slender-billed Crows of the trip cruised past the boat while we motored upriver.

Slender-billed Crow - Kinabatangan River, Sabah, Malaysia

Morning along the Kinabatangan River can be an excellent time of day to see hornbills. Rhinoceros, Black and Oriental Pied were all seen well, many of them perched in riverside trees.

Oriental Pied-Hornbill - Kinabatangan River, Sabah, Malaysia

There are eight species of hornbills that call Borneo home. While they utilize different habitats, in sufficiently large tracts of suitable habitat all eight species may be present. One reason why they can all coexist with minimal competition is that each species specializes on a particular prey item. Some species go after large figs, others medium or small figs, and still others are mostly carnivorous. As deforestation chips away at the edges of forest tracts, eventually the species that require vast tracts of intact habitat like the Helmeted Hornbill or White-crested Hornbill disappear slowly over time. Eventually, fragmented forests are only large enough for Oriental Pied Hornbills or Bushy-crested Hornbills, if that.

Oriental Pied-Hornbills - Kinabatangan River, Sabah, Malaysia

A boat trip down the Kinabatangan provides an excellent opportunity to compare the differences between the resident Pacific Swallows and migratory Barn Swallows.

Pacific Swallow - Kinabatangan River, Sabah, Malaysia

A pair of Crested Serpent-Eagles were keeping an eye out for serpentine shapes from prominent perches along the river.

Crested Serpent-Eagle - Kinabatangan River, Sabah, Malaysia

Heron types were conspicuous along the river with Purple Herons in particular putting on a show.

Purple Heron - Kinabatangan River, Sabah, Malaysia

Oriental Pied Hornbill - Kinabatangan River, Sabah, Malaysia

We rounded a bend in the river and some distant fluttering in a tree caught my eye so I stopped the boats. A closer look revealed them as Long-tailed Parakeets investigating the cavities in the tree. We missed this species in 2017 so the excellent though distant views were appreciated!

Long-tailed Parakeets - Kinabatangan River, Sabah, Malaysia

We investigated a quiet oxbow lake before returning to the lodge for a late breakfast. The sun was burning down on us by this point and not a hint of breeze could be found on the oxbox lake. The stifling heat limited the number of birds that were vocalizing, though a few White-chested Babblers sang out from the understory of the nearby forest. Ben spotted a pair of Rhinocerous Hornbills resting in the shade and closer inspection revealed that the male had a rodent of some kind in his beak. He gently passed it to the female who played with it for a while before swallowing it whole!

Rhinoceros Hornbills - Kinabatangan River, Sabah, Malaysia

In 2017 there were no trails that one could walk from the Borneo Nature Lodge but Ben heard from someone that one had recently been cut. Since we had no plans until our late afternoon boat cruise, Ben and I decided to lead a walk along this trail along with one of the guys working at the lodge.

Unidentified stick insect - Borneo Nature Lodge, Kinabatangan River, Sabah, Malaysia

Though the day was very warm which limited bird activity, we came away with some decent sightings. The highlight for everyone was of course a trio of Brown Wood-Owls - an adult and two youngsters - but we also saw a Black-and-yellow Broadbill and a pair of Hairy-backed Bulbuls at close range, and heard a Lesser Coucal and a White-crowned Shama.

Brown Wood-Owl - Borneo Nature Lodge, Kinabatangan River, Sabah, Malaysia

One of the travelers pointed out this amicable anuran perched beside a small pond next to the main lodge building. I believe it is Chalcorana megalonesa (Large White-lipped Frog) which was one of our most frequently encountered amphibians on the trip.

Large White-lipped Frog - Borneo Nature Lodge, Kinabatangan River, Sabah, Malaysia

That afternoon and evening we had two additional boat trips planned, which I will detail in the next blog post.

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Saturday, 13 July 2019

Borneo 2018: Part 6 (Kinabatangan River)

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