Breeding Process of Northern BooBook, a Natural Monument, Observed in Sangbuk-myeon, Ulju-gun

Discovered in a Pine Tree at the Center on June 19

The process of a pair of Northern BooBooks, a natural monument, nesting and raising their chicks in a pine tree in the hills of Sangbuk-myeon, Ulju-gun, has been observed.

‘Screech Owl’ observed at the Pine Nest in Jinaeri, Sangbuk-myeon, Ulju-gun. Photo by Yoon Giduk (Citizen Biologist)

The city reported that from June 19 to July 16, a pair of Northern BooBooks was observed breeding and raising two chicks in a pine tree nest located within a badminton center in Jinaeri, Sangbuk-myeon, Ulju-gun.

This observation began on June 19, when Kim Sangwoo, the center's director, discovered two Northern BooBook eggs and one chick in a nest on the pine tree.

Previously, in 2022, Kim had also observed and recorded two young Northern BooBooks visiting the same pine tree.

Upon being contacted by the center, Ulsan City visited the site on the same day, confirmed the presence of a male and female Northern BooBook sitting across from the pine tree, and installed an observation camera beneath the nest.

Starting July 2, Kim began monitoring the breeding process using the camera. On July 12, he captured footage at night of the mother bird bringing insects to the chicks near the nest and feeding them.

Finally, on July 16, after observing the chicks flapping their wings inside the nest, the birds disappeared. The now-empty nest was then occupied by a Grey-headed Woodpecker, which was seen foraging for food.

The Northern BooBook (scientific name: ninox japonica, English: Northern BooBook) is a summer migratory bird belonging to the owl family and is designated and protected as a natural monument.

It arrives in mid-April to breed and can be observed until mid-October. It inhabits lowlands and pine forests, sleeps during the day, and is active after dark. Its main diet consists of insects.

The nest is built in tree cavities, and three to four eggs are laid. The female incubates the eggs, with the incubation period lasting 25 to 28 days. The bird's body length is about 29 cm, and both sexes have the same coloration. The chest and belly are white with vertical brown stripes. The eyes are round and yellow.

In Ulsan, citizen biologist Yoon Giduk observed the species at Seonam Lake Park in July 2021. In June this year, Ulsan bird correspondents Cho Hyunpyo and Cho Woojin also recorded observations of the species in pine trees near Jeonggol, at the foot of Munsusan in Nam-gu.

Hong Seungmin, director of Jjaekjjaek Rest Area, stated, "Northern BooBooks sometimes reuse nests, so it is possible that the same individual returned, but without markings, it cannot be confirmed. If a bird has experienced nest destruction, it is likely to leave, so it is presumed that a new individual has arrived."

He added, "Above all, it is clear that this tree provides an excellent environment for birds to breed."

A city official stated, "We plan to continue monitoring next year to see if the Northern BooBook returns to the same tree. We will work to preserve locations where stories of migratory birds and people are connected, ensuring that birds can continue to find suitable habitats."