The egg of a crested ibis that began to hatch Sunday morning at a conservation center on Sadogashima Island, Niigata Prefecture, is expected to give way to Japan's second ibis chick bred in captivity as early as today, breeders at the center said.
Cracks have already developed on the egg's surface, and the tip of a tiny beak can be seen, the breeders said.
The chick began to hatch at around 7:30 a.m. The breeders said it usually takes between 20 and 40 hours for a chick to emerge.
The breeders said they heard a "pipping" sound coming from the egg late Saturday night when they picked it up from the incubator and held it to their ears.
The egg is among three laid in April by Yang Yang, a female ibis from China.
Yang Yang arrived in Japan in January 1999 with a male partner, You You, as a gift from Chinese President Jiang Zemin to the Emperor.
Yang Yang produced Japan's first ibis chick bred in captivity, Yu Yu, last May at the Sadogashima center, located in the Sea of Japan.
Yu Yu's birth on May 21, 1999, marked the culmination of an 18-year effort to breed ibises in captivity in Japan.
The wild ibis, whose scientific name is Nipponia Nippon, is distinguished by its red head feathers, gray plumage and hooked beak. It has been designated an endangered species by the International Council for Bird Preservation. Wild ibises no longer exist in Japan because they have been hunted and driven from their habitats to the verge of extinction. They began to disappear in the 1980s.