MANILA, Philippines (June 2026) — The Philippine eagle may be facing an even bigger challenge than previously believed. Scientists have discovered that the country’s national bird has exceptionally low genetic diversity, leaving the critically endangered species more vulnerable to disease, environmental changes, and inbreeding.
Researchers from the University of the Philippines Diliman, the Philippine Genome Center, the University of the Philippines Los Baños, and the Philippine Eagle Foundation reached the conclusion after completing one of the most comprehensive genomic studies ever conducted on the Philippine eagle.
The team analyzed DNA from 35 Philippine eagles under the care of the Philippine Eagle Foundation in Davao City to assemble a draft genome for the species. A genome contains an organism’s complete set of genetic material and serves as an important resource for understanding its health, evolution, and long-term survival.
Why genetic diversity matters
One of the study’s biggest findings is that Philippine eagles are genetically very similar to one another.
According to the researchers, low genetic diversity limits a species’ ability to adapt when new diseases emerge or environmental conditions change. If nearly every individual shares the same genetic traits, an illness or major ecological shift could affect the entire population in similar ways.
The lack of diversity also increases the risk of inbreeding. With fewer unrelated individuals available to reproduce, harmful genetic traits become more likely to appear in future generations. Over time, this can lead to reduced fertility, weaker immune systems, and physical abnormalities that make survival more difficult.
The researchers said these combined factors make the Philippine eagle more susceptible to extinction if conservation efforts fail to keep pace.
The decline may have started long before deforestation
While habitat loss remains the biggest modern threat to the species, the genomic data suggests the eagle’s population may have started shrinking thousands of years before widespread deforestation.
The scientists believe ancient environmental changes may have played a role. Rising sea levels could have fragmented what were once connected forests across Mindanao, isolating eagle populations and limiting opportunities for breeding.
They also noted that early human activity, including hunting or competition for prey, may have added pressure to already declining populations.
The researchers emphasized that these explanations remain hypotheses rather than confirmed causes, but they offer new insights into the species’ long-term history.
DNA could help shape future conservation
Beyond documenting the Philippine eagle’s genetic condition, the researchers say the draft genome can become a valuable conservation tool.
Genetic information can help conservationists make more informed breeding decisions, reduce the risks of inbreeding, and improve the long-term management of captive and wild populations.
The team believes genomics should become a larger part of wildlife conservation in the Philippines, providing a scientific framework that could also benefit other threatened species across the country.
Their findings were published in the peer-reviewed journal BMC Genomics under the study titled, “Genomic analysis reveals recent population decline and exceptionally low genome-wide heterozygosity of the critically endangered Philippine eagle, Pithecophaga jefferyi (Aves: Accipitridae).”
