About 200 mandarin ducks have been spotted in the stream Jungnangcheon in eastern Seoul, Seongdong-gu district office said Wednesday, sparking excitement here at the sighting of the relatively rare avian species.

According to the district office, the birds were sighted near the southern end of the bridge Yonbigyo in Geumho-dong. Yun Mu-bu, a professor of biology at Kyunghee University locally known as "Dr. Bird" for his research of local birds, reported the sightings to Seongdong-gu.

"Yun told me that there have been occasional sightings of one or two mandarin ducks in Seoul, but never of such size, making this occasion even more meaningful," Seongdong-gu chief Chong Won-oh said via the message he posted on X, formerly Twitter.

It is yet unclear why the birds decided to flock in the metropolitan area, but Yun said he wanted to notify the rest of the country of this rare occasion.

The mandarin duck is designated South Korea's natural monument No. 327 by the Cultural Heritage Administration of Korea. It is a symbol of love and fidelity in Asia, as they are mostly spotted in male-female pairs and had once been thought to pair for life.

While a sighting of a flock of such large size in Seoul is very rare, the mandarin duck is not a particularly rare species.

The species is categorized by the International Union for Conservation of Nature as a least-concern species -- lower risk in a pre-2001 categorization -- meaning they are not so rare to be evaluated as endangered or near-threatened, but not as common as the species defined as conservation-dependent. It is estimated that there are around 60,000 and 65,000 of the birds across the world, most of them native to East Asia.

The species had once been considered to be near-threatened in 1988, but the birds' status had gradually changed to be of lower risk/least concern around the turn of the century.

But sightings of the mandarin duck outside of Asia are quite rare, and occasional sightings in the wild have sparked headlines in countries like the US. In 2021, the US media reported that a mandarin duck was spotted at a park in Kansas, with speculations that it may have escaped from a local zoo or from the house of someone who had been keeping the bird as an exotic pet.