Photo/IllutrationA Ryukyu ashy minivet is spotted in a park in Tokyo in January. (Provided by Kiyoshi Omuro)

Kiyoshi Omuro couldn't believe his eyes when he spotted a wild bird indigenous to Okinawa Prefecture and the southern Kyushu region in a Tokyo park.

Omuro, 81, of Fuchu, Tokyo, took photos of the “Ryukyu sanshokui” (Ryukyu ashy minivet), which he saw in early January.

“I can’t believe that the bird is living in Tokyo,” he said.

The bird is often being spotted in Tokyo and neighboring Saitama Prefecture this winter for the first time.

The Environment Ministry says that the range of the Ryukyu ashy minivet may have moved northward due to global warming. Ryukyu is the old name of Okinawa.

The small bird, which belongs to the order Passeriformes, is about 20 centimeters in length. It is said to be a variant of ashy minivets, whose numbers are decreasing in Japan.

Until the 1970s, Ryukyu ashy minivets inhabited Okinawa and the southern parts of Kyushu.

When the Bird Research nonprofit organization asked its members and other people to report sightings of the bird in 2010, it generated reports from those living in the Kyushu, Shikoku and Kansai regions.

In subsequent years, those reports came from the Tokai region and some areas of the Kanto regions. And this winter, the reports came from Tokyo and Saitama for the first time.

This winter, the bird was seen in a total of 23 prefectures ranging from Okinawa to Saitama prefectures as of March 1.

As the bird’s coloring and chirping are low-keyed, it is highly unlikely that people brought the bird to Tokyo and Saitama as pets.

“The bird chirps in a distinctive voice. Because of that, if people were aware of the bird in the past, they would have reported their sightings to us. I think that the habitats of the bird have moved northward (to Tokyo and Saitama) recently,” said Katsura Mikami, a member of Bird Research.

In the Okinawa prefectural version of the Red Data book, the Ryukyu ashy minivet is classified as a near-threatened species.