[order] STRIGIFORMES | [family] Strigidae | [latin] Bubo blakistoni | [authority] Seebohm, 1884 | [UK] Blakistons Fish Owl | [FR] Ketupa de Blakiston | [DE] Riesen-Fischuhu | [ES] Buho Manchu | [NL] Blakistons Visuil
Members of the genus Bubo are the largest of the owls. Heavily built with powerful talons they are recognisable by their size, their prominent ear-tufts, and their eyes that vary in colour from yellow to brown but are frequently vivid orange. The genus, including the Asian fish owls of the genus Ketupa – now believed to be part of Bubo – comprises of 20 species ranging Eurasia, Indonesia, Africa and the Americas. DNA evidence suggests that the Snowy Owls of Nyctea and the fish owls of Scotopelia are also candidates for inclusion in this genus.
Bubo blakistoni blakistoni inhabits Hokkaido, northern Japan and Kuriles. One of the largest members of the Bubo genus. The lores of the facial disc are tawny-brown. There is a row of small white feathers above the eyes, around base of the bill and on the forehead. The rest of the head and upper parts are brown with buff feather tips. The back is darker, the mantle lighter and more rufous and barred darker. The wings are deep brown with buff-yellow bars. The tail is dark brown with 7-8 cream bars. Below is light brown with narrow paler cross-bars. The tarsi are feathered and the digits bare. The eyes are yellow; the bill bluish-grey with yellowish tips. The digits are grey, and the talons black. Females are larger than the males and have a total length in the order of 60-71cm. Bubo blakistoni doerriesi lives in Eastern Siberia south to Vladivostok and the Korean border. It is larger, with large white patch on top of head, and a less regularly marked tail. Bubo blakistoni karafutonis is found in Sakhalin. It is smaller and darker than the nominate race, especially on back and ear-coverts. Its tail has narrower dark brown bars and more of the the light bars. Bubo blakistoni piscivorus of Western Manchuria is paler than doerriesi. The basic colour of its under parts is greyish-white rather than buff-brown, and its tail-bars are not fully creamy-yellow. Like doerriesi, it has a large white occipital spot.
Eurasia : Northeast China, North Japan. Ketupa blakistoni is found in the coastal mountain ranges of eastern Siberia, north to Magadan, including Sakhalin Island, the southern Kuril Islands, and the Amur Basin, Russia, the mountains of Heilongjiang, Jilin and eastern Inner Mongolia, China, and central and eastern Hokkaido, Japan. It probably occurs in North Korea. Its population may be just a few hundred birds and it is declining in Russia and China, and possibly in Japan.
It inhabits dense forest, with large, old trees for nest-sites, near lakes, rivers, springs and shoals that do not freeze in winter. Also riverine forest and undisturbed coniferous forest along fast-flowing rivers. Any forested area that is well served by fast-flowing rivers that do not ice up in winter, and rocky sea coasts in the northernmost parts of its range are also frequented.
Because of food supply and general conditions, this bird does not breed every year. Laying begins in mid March, when the ground is still covered with snow. In dense forest, nests have been noted in hollow trees up to 12-18m high, as well as on fallen tree trunks and on the forest floor. Nest holes usually very wide and spacious.
Blakiston’s fish owls form pair bonds as early as their second year, reaching sexual maturity by age of 3. Courtship occurs from January-February, with a clutch of one or two eggs laid in March. The female incubates the clutch for about 5 weeks while the male brings food to the nest. Once the chicks hatch, the female continues to warm them during the day, but joins the male to bring food to the nest at night. Young fledge after about 50 days.
The adult Blakiston’s Fish Owl feeds mostly on fish (sometimes quite large ones, like pike, catfish, trout and salmon). It also eats a lot of crayfish and grass frogs. The latter are often fed to the young in large quantities. During the winter, it also takes mammals as large as hares, martens, cats and small dogs. Fish, crayfish and frogs are caught by wading through shallow water, or by waiting at the water’s edge and pouncing on the prey
Video Blakistons Fish Owl
copyright: J. del Hoyo
This owl has a very small, declining population because of widespread loss of riverine forest, increasing development along rivers and dam construction. It therefore qualifies as Endangered
This is a very large owl, having a wingspan of up to 2m. The size and the broad ear-tufts are good indicators. It can only really be confused with the Eurasian Eagle Owl, but the latter is paler, and has orange, not yellow eyes.
Blakiston’s Fish Owl begins hunting as soon as it becomes dark; although during the breeding season, when northern summer nights are quite short, it may be active at any time of the day or night. Unlike other owls, it spends a lot of its time on the ground, such that it makes trails along river banks.
This bird is rare and endangered throughout its range, and is listed as Endangered by Birdlife International. The population is believed to be no more than a few hundred pairs in Siberia and fewer than 100 individuals in Japan. In Siberia they gather around air holes in river ice in winter, making them vulnerable to hunters, trappers and fishermen. Protection programmes have been initiated, including the provision of nest boxes, and the population has recently shown signs of an increase.