You can hear what the Philippines used to sound like if you stand still long enough in the appropriate area of old-growth forest on the upper slopes of the Sierra Madre. Insects, wind, the sound of rain on leaves, and the calls of tiny birds that most people will never know the names of are all interwoven with the canopy’s layers and restlessness. Flowerpeckers and Warblers. birds with tails. Sparrows are unique to this island and cannot be found anywhere else on Earth. Standing amid that cacophony gives the impression that everything is alright. It isn’t.
One of Southeast Asia’s most biologically unique landmasses is Luzon. Due to its millions of years of isolation from the Asian mainland, it has an exceptionally high density of endemic species, which are birds and animals that have evolved only here. Passerines, the perching songbirds that comprise over half of all bird species on Earth, are among the most neglected. Dozens of them are found in narrow ecological ranges on Luzon, associated with particular tree species, elevations, and forest interiors that are currently vanishing at a rate that truly unnerves scientists.
One aspect of the issue is that the numbers aren’t exact. There aren’t many monitoring programs in Luzon. Despite being enthusiastic and expanding, the birding community is operating against a baseline that was never properly established in the first place due to the island’s size, challenging terrain, and ongoing lack of funding. When you never fully documented what you had, it’s difficult to quantify what you’re losing. It is difficult to deal with this uncertainty, particularly when volunteer surveyors and field biologists are discovering fewer individuals of species that were previously thought to be consistently common.
The dangers are not enigmatic. The main factor is habitat loss. Over the past century, Luzon’s lowland and mid-elevation forests have drastically decreased, and what is left is becoming more dispersed, with green areas encircled by roads, farms, and populated areas
Among the first to vanish from degraded edges are passerines that rely on the interior of the forest. They have trouble adapting. They are not very mobile. They just become less noticeable, then nonexistent, then nonexistent. The issue is made worse by illegal trapping. A few weeks ago, an illegal snare on Mount Malingudo in Apayao produced a Luzon Bleeding-heart, a near-threatened ground dove that can only be found there. After five days in captivity, the bird was released. It was a little tale that got little attention. It most likely wasn’t uncommon.
Small songbirds don’t create the same sense of urgency as a Philippine Eagle circling overhead, which makes the situation with passerines especially challenging. They don’t take as striking pictures. If you haven’t taken the time to learn to listen for them, they are more difficult to see, recognize, and care about. Even with its limited scope, conservation efforts tend to focus on animals that evoke wonder. Those who are quiet fall behind. These birds are currently quiet in two ways: their numbers are declining and they are hardly mentioned in public discourse.
Work is being done. By consistently documenting the biodiversity of the Philippines, wildlife photographers are increasing awareness. The use of community-based monitoring is gradually growing. Younger Filipino naturalists are accurately recording sightings thanks in part to their training on citizen science platforms and social media networks. Over the next ten years, data density might increase to the point where conservationists have more reliable information. By then, the forest patches that those birds rely on might have shrunk to the point of irreversibility.
When you consider this, you are struck by how quickly a landscape can become acoustically flat. Forests don’t suddenly become silent. One species is gradually reduced, then eliminated, then replaced by generalists, and finally there is silence where complexity once existed. The shift has already occurred by the time most people become aware of it. There is still a lot of sound in the Luzon canopy. However, those who have been paying close attention for years will tell you that the sound has changed. That distinction is important. It’s still unclear if enough people will conclude that it matters in time.
