Spectacle of 114,000 Rooks... Taehwa River in Ulsan Confirmed as a Winter Migratory Bird Paradise

111 Species and 121,000 Winter Birds... Up 36% from Last Year

AI-Based Ecological Survey Highlights Biodiversity of Taehwa River and Dongcheon

The areas around the Taehwa River and Dongcheon have once again been confirmed as major wintering and roosting sites for migratory birds.

The city of Ulsan announced that, according to the results of the "Winter Wildlife Monitoring" conducted from November 1 of last year to March 31 of this year in the areas around the Taehwa River, Dongcheon, and Hoeya River, a total of 111 species and 121,733 individual winter birds were observed.

This represents an increase of nine species and approximately 36.5% more individuals compared to the previous year, when 102 species and 89,166 birds were observed.

In particular, the numbers of tufted ducks, mandarin ducks, and Eurasian coots increased significantly, and 15 new species—including Baikal teal, eastern spot-billed duck, goldcrest, and northern lapwing—were recorded, further enriching Ulsan's biodiversity.

Ulsan's representative winter migratory bird, the rook, was observed in a record-breaking number of 114,119 individuals (as of February 21), reaffirming its status as the country's largest roosting site.

This survey utilized the AI-based individual counting program "CountThings from photos," which has been in use since last year, enabling the collection of more objective and precise ecological data.

Kim Jinhan of the Korea Waterbird Network evaluated, "Thanks to scientific surveys using AI-based technology, highly reliable data is being accumulated each year."

Kim Seongsu, an avian ecologist who has studied rooks since 2000, analyzed, "A 'V-shaped rebound' of approximately 36.5% compared to the previous year was observed," adding, "This is the result of changes in the arrival time at wintering sites due to lower temperatures at breeding grounds, combined with an increase in the number of individuals."

He further explained, "As southern populations from Japan and Jeju Island joined the Ulsan bamboo groves before heading north, a record-breaking figure of about 114,000 birds was recorded, indicating the exceptionally high ecological capacity of the Taehwa River bamboo forest."

This survey also identified a significant number of endangered species and natural monuments. A total of 15 species were observed, including the endangered and nationally designated natural monuments such as the golden eagle, Steller's sea eagle, white-tailed eagle, and otter (Class I), as well as the hooded crane, Eurasian eagle-owl, and northern goshawk (Class II).

In particular, up to 200 eagles were observed gathering in flocks around Samho Island in Daun-dong, creating a spectacular sight.

The city of Ulsan plans to incorporate the results of this survey into the Taehwa River Migratory Bird Information System to share with citizens, and will continue to expand migratory bird habitat protection policies and ecotourism programs based on scientific ecological data.

The Ulsan Biodiversity Center, which conducted this survey, plans to newly operate a "Morning Flight Observation Week" for citizens next year, following last year’s rook murmuration experience program.

Ulsan's representative winter migratory bird, the rook, with a record high number of 114,119 observed this year (as of February 21).

This content was produced with the assistance of AI translation services.