Philippine eagle has unique evolutionary history

The country’s national bird, the Philippine Eagle, is one of a kind, not
only because it is found nowhere else, but also since it has a unique
evolutionary history, clearly distinguishing it from other giant eagles
once thought of as its immediate family.

At least this is what a recent study of the Philippine Eagles’ DNA suggests.

Scientists from the University of Michigan USA analyzed DNA isolated from
blood samples of Philippine Eagle and those of the Harpy Eagle and Crested
Eagles of the Americas and the New Guinea Harpy Eagle of New Guinea, all
equal heavy weights of the bird world. All of the last 3 giants named are
close relatives as revealed by DNA sequences, but only remotely related to
the Philippine Eagle.

According to Dr. David Mindell of the University of Michigan, the
Philippine Eagle was once grouped with 5 bird giants (the other two being
the Crowned Eagle and the Solitary Eagle in the Americas) because all
these species share extremely large size, with female wing-spans between
1.5 to 2.0 m and female body weights from 6 to 9 kg.

He also said that all of the 5 traditional “harpy eagle group” members
live in tropical forests, feeding mainly on medium-sized mammals.

“But based on the genetic analyses, the similarities between the
Philippine Eagle and the other harpies resulted not from kinship but from
convergent change, driven by natural selection for reproductive success in
tropical forests and a shared taste for mammals”, Dr. Mindell added.

Amazingly, Mindell’s team also found that the only distant relatives of
Philippine Eagles are snake eagles found elsewhere in Southeast Asia and
far Africa. In the Philippines, it is distantly related to the
featherweight but equally imposing Serpent Eagle, which breeds in this
country but is also common in Asia.

The study of Dr, Mindell’s team passed expert reviews and was published in
the scientific journal “Molecular Phylogenetics and Evolution”.

The country’s conservation flagship, the Philippine Eagle is undoubtedly a
world celebrity. Dubbed “King of Birds”, this top forest predator is
unrivaled by any Philippine wildlife in terms of local and international
publicity and interest.

The famous aviator Charles Lindbergh called it the “world’s noblest flyer”
to call the world’s attention to its troubles. In 2000, famed scientist
E.O. Wilson listed the Philippine Eagle in the Hundred Heart Beat Club –
animals likely to become extinct in the near future.

But all the fame and publicity has not spared the species from
endangerment. Its population status remains precarious as recent estimates
suggest that there may be 500 or fewer pairs of them left in the wild.

Sadly, eagles are still losing the forests which they cannot live without.
Barely 3 % of the country’s old growth forest remains, most of them
threatened by expanding agriculture, illegal logging and mining.

Many eagles are also still being shot or trapped, either for food, out of
despair over livestock allegedly lost to nesting eagles, or out of plain
curiosity and ignorance.

In the face of deforestation and continued persecution, the future of our
national bird remains bleak.

According to Dennis Salvador, Philippine Eagle Foundation Executive
Director, the recent finding of Dr. Mindell’s team definitely will not
save the eagles overnight, but can be another compelling reason why
Philippine Eagles need to be saved.

“They are a unique and priceless component of the natural heritage not
only of the Philippines but also of the world” he added.

DNA is an abbreviation for deoxyribonucleic acid, the material of
inheritance. It is made of chemicals which provide the instructions
influencing how organisms should look and behave. Ask why a dog looks and
acts like a dog, and humans not as chimpanzees, and you will find that the
DNA is behind that.