Sometimes a simple egg hatching can be a victory. That's the case in the Philippines, where a threatened bird of prey known as the Pinsker's hawk–eagle (Nisaetus pinskeri) has been bred in captivity for the first time.

The Philippine Eagle Foundation (PEF) reports that the Pinsker's chick hatched on April 2 at its breeding program in the village of Malagos and weighed 57.2 grams. Its parents are both rehabilitated birds that were turned over to PEF after being injured in the wild. The chick's gender will not be known until it matures in four to five years.

The Pinsker's hawk–eagle is endemic to the Philippines and, to date, has not been heavily studied by science. In fact, its taxonomy is actually still a matter of debate. Some scientists consider it a subspecies of the Philippine hawk–eagle and call it Spizaetus philippensis pinskeri. Others consider it a full species and classify it as either N. pinskeri or Spizaetus pinskeri. BirdLife International, which tracks the health of bird species around the world, does not at this time accept Pinsker's hawk–eagle as its own species; the organization estimates the total wild population of both Philippine and Pinsker's hawk–eagles at between 1,000 and 2,500 individuals.

PEF has been successfully breeding Philippine eagles (Pithecophaga jefferyi) for two decades. Its first artificially inseminated eagle hatched in January 1992 after 10 years of research. Philippine eagles remain critically endangered, with approximately 400 pairs in the wild and 36 birds housed at the PEF center.

PEF used its experience with the Philippine eagle for its Pinsker's hawk–eagle breeding efforts, but a lot remains to be learned about successfully breeding and raising the birds, let alone keeping them safe in the wild. "Nothing is known about its breeding biology," PEF executive director Dennis Salvador told The Star. He told The Inquirer that foundation scientists will be monitoring the chick as it progresses and that he hopes "it will survive and we will be able to improve our breeding techniques of this species through this experience."

A number of factors could affect the chick's survival, according to Anna Mae Sumaya, curator of PEF's conservation breeding program. "Basic things such as food, temperature and response to stimulus are being monitored." This will be the first time that the developmental stages for this species have been recorded, she says.

Hawks and eagles both come from the family Accipitridae, and hawk–eagles are considered an intermediate between those other types of birds of prey. BirdLife International recognizes 16 different species of hawk–eagle and lists the Javan hawk–eagle (Nisaetus bartelsi) as endangered and the Flores hawk–eagle (Nisaetus floris) of Indonesia as critically endangered.

Photo: Composite image of the 10-day-old Pinsker's hawk–eagle chick and its mother, courtesy of Philippine Eagle Foundation

(Updated April 19 to include a quote about monitoring the chick's development.)