Birds, Orangutans

Having moved through so many different types of forest, each time I looked up, I noticed how the canopy changed, some stretching high and open, others closing in tightly, layering over one another. It’s a world of its own up there, far removed from the forest floor and the life below. Birdlife thrives in many forms, from raptors hunting in the upper canopy and the air above it, to owls calling through the night, often unseen, and the steady tap, tap, tap of a woodpecker working its way along the bark in search of insects.

Between it all, smaller birds move constantly through the leaves, often harder to spot. Warblers and flycatchers flick between branches in quick bursts, catching insects mid-air or picking them off the underside of leaves. Tiny flowerpeckers, some of the smallest birds in the forest, feed on soft fruits and berries, helping disperse seeds as they move through the canopy. Sunbirds take on a different role, feeding on nectar and, in the process, pollinating flowering plants, much like hummingbirds do elsewhere in the world.

Not all behaviour is as straightforward as it seems. The hawk-cuckoo, for instance, takes a rather clever shortcut, skipping the effort of building its own nest altogether. Instead, it targets smaller birds like warblers, laying its egg in their nest and leaving the hard work to them. The unsuspecting warbler then takes on the role of a surrogate parent, raising a chick that isn’t even its own.

While contemplating the cheekiness of the cuckoos, my attention shifts to the bird calls around me. They’re different, and they seem to be coming from all directions. At first it feels scattered, the melodic song of a warbler broken by the raspy chatter of a babbler. Looking up into the canopy, I begin to understand what I’m hearing. The birds aren’t in one tight group, but spread through the mid to upper canopy, moving loosely together. I catch a glimpse of one darting past, then pause, and another follows through the same space, then another, each appearing briefly before disappearing again. They move at different heights and speeds, and the longer I watch, the more I realise they are part of a mixed-species flock, sometimes called a bird wave, all moving in the same direction.

The benefit of this mixed flock is increased foraging efficiency. As they pass through, insects are flushed out from the foliage, making them easier to catch. Some birds watch others to identify productive feeding spots, and because the flock is mixed, competition is reduced, with each species using slightly different diets and foraging techniques. At the same time, more alert species act as an early warning system, reacting quickly to sudden movement or danger. This not only helps the group stay safe from predators but also makes it harder for predators to focus on a single target, as multiple species move in different directions at once.

Not all these birds stay here year-round. Migratory species travel long distances, many arriving from northern Asia to escape colder climates and follow seasonal food sources. These forests are a vital stopover, offering shelter and a chance to refuel before continuing their journey.

Listening to the canopy, it becomes harder to tell which birds belong here and which are only passing through. But whether resident or migratory, they all rely on this forest, even if only for a short part of their journey.