Tarsiers cling to Tacloban’s forests amid city’s growth

MANILA, Philippines — On most nights, the work began in the dark.

A team of at least three observers walked quietly in single file, moving slowly along roads, trails and footpaths with flashlights trained on vegetation at both sides of the path. They were looking for a small, nocturnal primate that has long drawn curiosity—and, in many places, mounting concern: the Philippine tarsier.

Between July 29, 2022, and Feb. 25, 2023, the night surveys documented what had previously been only anecdotal in Tacloban City: Philippine tarsiers were present in forest patches across three barangays, despite rapid urban expansion in a city that has been rebuilding and growing quickly since becoming highly urbanized in 2008.

Researchers recorded nine independent encounters across the three sites—one in Barangay Santa Elena, three in Barangay Salvacion and five in Barangay Utap—marking what the study describes as the first research documenting the Philippine tarsier within an urban landscape.

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The findings are detailed in a study, “Philippine Tarsier in Tacloban City, Leyte, the Philippines: Amid Urban Sprawl,” by Richard B. Parilla, Ann Gelanie C. Tarrayo and Eulito V. Casas Jr. of the Division of Natural Sciences and Mathematics, University of the Philippines Tacloban College.

A threatened primate in an urbanizing city

The Philippine tarsier (Tarsius syrichta) is found in forests on Bohol, Mindanao, Samar, Leyte and Biliran islands and is described in the study as among the least-studied primates in the world.

The researchers noted that the species’ conservation status has shifted over time: It was categorized as endangered from 1986 to 1990 by the International Union for Conservation of Nature (IUCN) due to habitat destruction, later downgraded to lower risk and then data deficient, before being classified as near threatened from 2008 through the last assessment in 2015. No assessments have been conducted since then, and the study cites concerns that the most recent IUCN assessment may no longer hold true in places facing severe threats.

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In the Philippines, the study noted that the species is listed as “other threatened species” under the National Redlist of Threatened Fauna.

For the Tacloban City study, the goal was direct and practical: validate and document the tarsier’s presence, evaluate threats observed in the field, and examine what rapid urban growth could mean for the species and its habitat—particularly on Leyte, where fewer studies have been conducted compared with Bohol.

Where the tarsiers were found

The surveys focused on forest patches in Barangay Santa Elena, Barangay Salvacion and Barangay Utap—areas selected not only because of reported sightings, but also because the study described them as barangays where urban sprawl is rapidly occurring.

The study described Tacloban City as having a total area of 20,172 hectares, with 4,204.18 hectares classified as timberland and forest areas, including 2,855.11 hectares of closed forest, based on the city’s comprehensive land use plan (CLUP) for 2017-2025.

Each barangay had a distinct setting.

• Barangay Santa Elena, in the northwestern side, covers about 942.50 hectares, with about 29% covered by secondary growth forest. The study described scattered Ficus species and other vegetation, including buyo-buyo (Piper aduncum), identified as an invasive plant species.
• Barangay Salvacion, south of Santa Elena, has a land area of about 661.30 hectares, with about 21.84% described as mixed secondary growth forest and plantation, with Ficus species alongside trees such as mahogany (Swietenia macrophylla) and Gmelina arborea.
• Barangay Utap, near the downtown and commercial area, covers 194 hectares, with about 70% described as mixed secondary growth forest and plantation, including Ficus species and other trees, particularly along a steep, mountainous slope.

Nights were more revealing than days

The study found that night surveys were the most effective way to detect tarsiers in the sites surveyed.

Most encounters occurred between 6 and 8 p.m. Nearly all were found through active searching, with one detected after the team followed a loud vocalization. In each case, the tarsiers were seen clinging to tree stems at heights of about 2 to 3 meters above the ground. The stems had an average diameter at breast height (DBH) of 3.3 centimeters.

Daytime searches and camera traps, by contrast, did not produce any tarsier detections at the sites.

The researchers described daytime searches for sleeping tarsiers as challenging, noting that sleeping sites cited in other studies tend to be in dense thickets with tall trees and lianas—habitats that, in this study, were often located on steep slopes and difficult terrain.

Camera traps also came with limitations discussed in the paper. The researchers cited other findings that camera traps can emit infrared light and audible sounds that can trigger avoidance behavior in tarsiers, and noted that camera placement can introduce detection biases depending on whether cameras are on trails or off trails.

One capture, and a closer look

Hand capture was attempted to gather details not possible through distant observation, but steep slopes made it difficult.

Only one capture attempt succeeded, resulting in the capture of a subadult male. The tarsier measured 302 millimeters in total body length and 200 millimeters in tail length. After measurements were recorded, the animal was released at the site of capture, and no markings were applied.

Threats recorded in all three sites

Alongside the encounters, the study recorded disturbances and threats it associated largely with human activity.

Across the three barangays, the researchers observed threats such as land conversion for housing, commercial development, infrastructure and agriculture; biological resource exploitation including illegal wildlife hunting and timber poaching; problematic animals such as feral cats and stray dogs; tourism; and solid waste.

Using the IUCN-CMP unified classification of direct threats, the study assessed these common threats as having high impacts on the continued survival of tarsiers in the area. It also assessed light pollution, noise pollution and natural disturbances such as droughts, storms and flooding as having high impacts on persistence.

Some threats were specific to certain barangays. The study noted military exercises and noise pollution in Barangay Santa Elena and Barangay Utap; timber poaching and wildlife hunting in Barangay Santa Elena and Barangay Salvacion; and ecosystem modification in Barangay Salvacion near Balugo Falls, where tourism and recreation activities were described as flourishing.

The study also pointed to one contrast: Barangay Utap’s forest habitat was noted to be cleaner, with trash and other solid waste described as absent.

Why the findings matter

The study framed Tacloban City as a test case for biodiversity conservation under urban pressure.

It described the Philippine tarsier as a species that can occur in multiple habitat types, citing earlier work indicating it can thrive not only in intact forests but also in mixed secondary forests and adjacent to agricultural lands. In Tacloban, the researchers also noted—in direct observation and personal communications with local guides and residents—that the city’s forest habitat harbors a diversity of fauna, including insects, amphibians, reptiles, rodents and bats.

The study argued that the forests of Tacloban City can be considered an important biodiversity area and should be recognized in future amendments of the city’s CLUP.

It also emphasized that, while the tarsier’s presence suggests resilience, ongoing urbanization can intensify pressures: habitat clearing and conversion can reduce sleeping and foraging sites, while infrastructure and road construction can fragment habitat and isolate populations. Artificial lighting and urban noise were also cited as disruptive to nocturnal species and wildlife behavior.

Solid waste was highlighted as another concern, with the study citing a growing solid waste challenge in Tacloban City and noting how improperly managed waste can attract animals that may act as predators or vectors of disease.

A call for monitoring, collaboration

Despite documenting the species in an urban landscape, the study’s message was not celebratory. It was cautionary.

The researchers called for immediate attention and action to help ensure the tarsier population’s continued existence in Tacloban City. Their recommendations included more research focused on tarsiers in urban landscapes, regular biodiversity monitoring, and habitat improvement through collaborative partnerships among stakeholders—local communities, academe, local government institutions and nongovernment organizations.

The study concluded that while human-induced disturbances can be regulated and managed, continued forest degradation could lead to habitat loss for reproduction and interaction. It also recommended further research on the tarsier’s ecology in remaining forest patches in Tacloban City and on the roles of the community and local government in conservation, to help develop a sound management strategy for tarsiers in the city.

TAGS: Tacloban City, tarsiers