TAÏ NATIONAL PARK, Côte d’Ivoire — The path that leads through the rainforest towards a nesting site for one of its most curious inhabitants is not made by humans but by animals.
“It might be half a million years old, this animal path,” says Michele Menegon, a herpetologist and regular visitor to Taï National Park, in southwestern Côte d’Ivoire. It could of course be younger, he adds, but such a clear trail through the forest, following the contour of a ridge, is likely to be an ancient one — maintained by the passage of both Taï’s great and small, from forest elephants (Loxodonta cyclotis) to diminutive antelopes like the Maxwell’s duiker (Philantomba maxwellii), whose piles of tiny black droppings are visible beside the path.
The forest floor here is relatively clear of undergrowth. Dominant trees, supported by huge buttress roots, hold their canopies out of sight above; they restrict the sunlight and curtail the growth below.
“I’ve never been in a forest with this density of giant forest trees,” Menegon says.
The guide, Gliman Hyacinthe, a ranger with the Ivorian Office of Parks and Reserves (OIPR), identifies one of the tree giants as kosipo — Entandrophragma candollei — one of the mahoganies.
This part of the forest is boulder-strewn, situated as it is on the slope beneath a large dome of granite whose summit breaks through the canopy of trees but is barely visible from within the forest.
The bird being sought is the white-necked picathartes (Picathartes gymnocephalus), which nests in caves and beneath overhangs. But it’s not just the picathartes, also known as the rockfowl, that is drawn to these boulders.
Hyacinthe indicates a small overhang where, going by the spoor, Jentink’s duikers (Cephalophus jentinki) sheltered overnight from the rain. The Jentink’s is the largest of the seven species of duiker resident in Taï. It has a two-tone coat, the upper half dark and the flanks and underparts paler, giving it a tapir-like appearance. They, like the smaller zebra duiker (Cephalophus zebra) and the picathartes, are unique to the Upper Guinean rainforest, of which Taï National Park is the largest intact remnant.
“The [Jentink’s] population is doing really well here,” says Menegon, who is also the director of biodiversity conservation with South Africa-based nonprofit Leadership for Conservation in Africa (LCA). The group is partnering with a local NGO, Eburny Biodiversity Conservation (EBURCO), to support OIPR’s work in Taï.
There are other signs of healthy animal activity. Holes in the ground indicate where red river hogs (Potamochoerus porcus) — West Africa’s version of the bushpig (Potamochoerus larvatus) — have been rooting around for food. A midden deposited by an African civet (Civettictis civetta), reveals this small carnivore’s appetite for Taï’s ubiquitous millipedes. And through the chorus of forest bird calls, Hyacinthe identifies the loulou, or Senegal coucal (Centropus senegalensis), a large bird with brown wings and a black head, burbling somewhere out of sight in the thick riverine creepers fringing the nearby Hana river.
Above the canopy of the forest, the air is filled with the sound of heavy wingbeats from hornbills issuing loud nasal wails. They remain out of sight but could be black-and-white-casqued hornbills (Bycanistes subcylindricus) flocking to the crown of a fruit-bearing tree.
They — along with the monkeys, chimpanzees and even duikers and river hogs — likely play a key role in dispersing seeds.
Studies in a part of Cameroon’s Lower Guinean rainforest, for instance, found that black-casqued wattled hornbills (Ceratogymna atrata), piping hornbills (Bycanistes fistulator) and white-thighed hornbills (Bycanistes albotibialis) disperse the seeds of more than 50 tree and liana species, with most carried more than half a kilometer (about 0.3 miles) from the parent plant and some transported more than 6 km (3.5 mi) away. Black-casqued and piping hornbills are among nine hornbill species also resident in Taï.
Hyacinthe’s phone makes a bleeping sound as he unwraps it from a plastic bag. Then, using the GPS app, he rediscovers a trail he recorded a year ago. It leads to the picathartes colony.
Machete in hand to clear the odd branch, he leads the group up a slope thick with leaf litter and fallen pods, past a fallen, decaying tree trunk entangled with vines, to a large rocky overhang where three mud-cup nests are attached to the stone wall. The nests are grey with age, but their rims are reddish-brown from freshly deposited mud, indicating that the picathartes have been doing some renovations ahead of this year’s breeding season.
After 30 minutes spent waiting near the nests, the picathartes still don’t show up. “They’re very shy. It’s easier to see them when they have eggs. Then they don’t go far,” says Hyacinthe, who discovered the nests last year while guiding a documentary film crew in the area.
The ranger leads the group to another promising site on a steep slope. It’s a rocky gorge filled with small boulders covered in moss.
A group of birds, picathartes-sized, scurry across the boulders, but they aren’t the target species. Like the picathartes, however, they are unique to this type of rainforest. Their vivid red heads, dark bodies and white breasts identify them as white-breasted guinea fowl (Agelastes meleagrides).
In the canopy of the tree giants, a mixed party of colobus monkeys drops branches and flowers onto the slope below as they feed and move through the treetops.
The next day, Hyacinthe leads the observers back to the moss-filled gully. They sit patiently for an hour, listening to the incessant trills of crickets and frogs and the swish of colobus monkeys once more crashing through the canopy. Red-chested cuckoos (Cuculus solitarius), who are year-round residents here, issue their distinctive three-note calls.
