飼育下生まれのオガサワラカワラヒワのペアが繁殖しました！

The Ogasawara Greenfinch is a bird found only in the Ogasawara Islands and is considered to be at extremely high risk of extinction in the wild. As part of ex-situ conservation efforts for this species, breeding programs are being conducted at Ueno Zoo and facilities on Chichijima Island.

At Ueno Zoo, two Bonin Greenfinches born in captivity last year have paired up and bred, resulting in the successful fledged of three chicks. For species that are at high risk of extinction in the wild, being able to breed for multiple generations in captivity in this way is extremely important for increasing the population and preventing extinction.

background

Ueno Zoo has been working to contribute to the conservation of the Bonin Greenfinch by developing and promoting breeding techniques for closely related species. In March 2025, they received two wild Bonin Greenfinches from a facility on Chichijima Island and began breeding them, and in July 2025, two chicks fledged. At the Chichijima facility, a total of four chicks fledged between June and July of the same year.

Subsequently, in October 2025, the two birds were moved from the facility on Chichijima Island to Ueno Zoo, and in 2026, efforts were made to breed them with a new pair.

Breeding status in 2026

Ueno Zoo
Number of chicks to fledge: 3
Father: Born June 15, 2025 at a facility on Chichijima Island.
Arriving at Ueno Zoo on October 15, 2025
Mother born June 30, 2025 Ueno Zoo

At the Chichijima facility, they have also successfully bred pairs of animals born in captivity.
Ogasawara Nature and Culture Research Institute, Animal Husbandry Facility
Breeding pair 1: 4 chicks hatched between June 14th and 16th, 2026.
Mating behavior was observed in captive pair 2 by June 18, 2026.

• Chichijima facility, Tokyo
One breeding pair; 2 chicks left the nest.
Breeding pair 2: Laid eggs (4 eggs total) from June 4, 2026.

Domestic breeding situation (as of June 15, 2026)
・8 birds Ueno Zoological Gardens (3 of which were born in 2026)
- Chichijima Island: 16 birds (6 of which were born in 2026)