An organization promoting the revival of the Oriental White Stork, which went extinct in Japan almost half a century ago, said at least one egg laid by a nesting female has apparently hatched in Naruto, Tokushima Prefecture.

The hatching would be the first outside a sanctuary that was set up in the Kinki region in 2007 to reintroduce the birds to nature.

The parent storks flew to the city in 2015 from Toyooka, Hyogo Prefecture, where the sanctuary, called Hyogo Park, was established.

The organization monitoring the nesting storks said Wednesday it witnessed one of the parents vomiting up food, suggesting it may be feeding a chick or chicks, but no hatchling has been sighted yet. The first egg is believed to have been laid around Feb. 16.

The Oriental White Stork is a designated national treasure. The last wild bird was captured for its own protection in 1971 in Toyooka after sustaining an injury, according to Hyogo Park.

The species has been breeding successfully around Toyooka since the sanctuary was set up. No other instances of it breeding outside the area had been confirmed until now.

The Tokushima Prefectural Government said last year it found crows stealing and eating stork eggs laid in the city in March last year, but that the eggs were infertile to begin with.

The suspected hatching has provided "enormous hope and courage," Hyogo Park said in a statement on Wednesday.

"We will root for the hatchling until it grows up and leaves the nest," said Satoshi Yamagishi, the park's superintendent.