Hollowed-out homes demolished by deforestation

Humans have long been demolishing the forest for the sake of land development—uprooting trees and displacing forest residents. 

Along with this destructive expansion, birds are stripped of their tree cavities, leaving them practically homeless, which thins their survivability and lowers their numbers.

To safeguard the abode of forest birds, tree holes in the Subic Watershed Forest Reserve, Zambales, Philippines, were surveyed by researchers from the University of the Philippines Diliman – College of Science (UPD-CS) along with other environmental institutions.

Dwelling in life and death

According to the study, there are 10 species of cavity-nesting birds sheltering in both living and dead native trees in Subic. They are found to usually nest in kupang trees (Parkia timoriana) and white lauan trees (Shorea contorta). 

Their crafted tree cavity, often made by an excavating bird like a woodpecker, is an important structure that is interconnected to the woodlands’ web of life.

This connection is called ‘nest web interactions.’ It refers to how animals, mostly birds, form relationships through their shared use or competition over tree cavities for nesting spaces.

The hollowed-out homes become for birds and other forest residents such as insects, mammals, invertebrates, and even fungi. 

“This study is the second of its kind in Asia—and the first in the Philippines—that examines nest web interactions at the community level,” the team of biologists shared. 

In this network, primary excavators use their beaks to build their own cavities, usually to search for food. 

Contrarily, secondary cavity nesters use already-dug cavities for their own good, such as for shelter, reproduction, and protection against predators.

Fussy forest inhabitants

Using multinomial logistic regression modelling, the researchers discovered that birds are selective with their tree cavity. They are fussy with the depth, volume, and entrance area of their chosen tree holes.

In fact, primary cavity nesters intricately and tirelessly excavate their own cavities, with hairy woodpeckers spending about 20 days to craft their home, noted the US Forest Service (.gov).

Meanwhile, if secondary cavity nesters do not identify tree holes that meet their standards, they would have to search the entire forest for hours and find empty cavities before nightfall to avoid predators.

As such, cutting down trees with already-crafted cavities makes forest birds either homeless or stalling for death. 

According to Niringiyimana (2022), decaying and larger trees especially need to be left alone standing in the forest. 

He highlighted that these trees are mostly preferred by cavity-nesting birds as favourable nesting sites, since these offer softer wood for easier excavation and abundant foods such as insects and larvae.  

Protecting the peckers

While woodpeckers may be just tiny specks in the temperate forest of Europe and subtropical South America, they are an indispensable asset for the ecological well-being of a tropical forest. 

The study revealed that 63% of nests used by non-excavator birds were made by woodpeckers—underlining how their craftsmanship is greatly appreciated by the whole woodland.

However, excessive deforestation has degraded the natural environment, destroying the homes of woodpeckers and undervaluing their importance to the forest ecosystem.

In fact, the Philippines has already lost 60% of its forest cover over the past 80 years, with 47,000 hectares of land being trimmed annually, according to the Philippine Clearing House Mechanism.

“These results highlight the urgent need to prioritize research and conservation efforts for primary excavators—birds like woodpeckers that create their own nesting holes—in the Philippines, where both these species and those that rely on their nesting sites remain largely understudied,” they added.

In light of this, the study handed out conservation tools like developing species-specific nest boxes to meet the standards of cavity nesters. 

This effort will be vital to birds included in the Philippine Red List Critically Endangered and Vulnerable species such as the Blue-naped Parrot (Tanygnathus lucionensis) and Luzon Hornbill (Penelopides manillae). 

Sowing seeds for shelter

With the forest facing centuries of harassment from its supposed stewards, many trees are left scarred, felled, or forgotten. 

As such, environmentalists now urge lawmakers to enact policies for a steadfast revitalization for the countless demolished forests—returning the homes of birds that have long been lost by forest denudation.

As the study emphasizes, sowing tree seedlings is the first flight toward true environmental stewardship. This will not only plant possible places for hollowed-out homes but also purify the demolished woodlands from the taints of deforestation.