Calls by adults are identified by a ‘boo-boo uoo’ or ‘foo-foroo’. Adults perform duets, where males and females call in quick succession. The pattern changes across populations but for those on the mainland, males contribute the first and third notes and females contribute the second and fourth. Occasionally the order is reversed with the female initiating the duet, but this occurs only when the pair is agitated.
Like all owls, Blakiston's fish owls rely heavily on visual and auditory stimuli, and feature unique physical adaptations. The facial disk feather arrangement serves to gather sounds and increase accuracy when detecting prey movement. Large, immobile eyes allow the owls to capture enough light to hunt prey at night.
Communication Channels: acoustic
Other Communication Modes: duets
Perception Channels: visual ; tactile ; acoustic ; chemical
IUCN Red List recognizes this species as a rare and endangered bird. Despite not living among humans, this species occurs in timber rich areas that are valued for their natural resources, primarily in Japan and Russia. As such, habitat destruction by the logging industry is a concern for this species. Poachers have been known to kill Blakiston's fish owls. With an estimated 5,000 individuals remaining in the wild, saving every bit of forest and enforcing species management is of dire importance.
IUCN Red List of Threatened Species: endangered
There are no known adverse effects of Blakiston's fish owls on humans.
The regions where Blakiston's fish owls are found are largely unpopulated by humans and there are no direct links reported between this species and humans.
Blakiston's fish owls impact the populations of fish, small vertebrate, and other organisms they feed on.
Bubo blakistonii mainly feeds on fish, and depends on open water or holes in the ice where it may fly down and make use of its powerful claws. It also hunts on the ground and in shallow water for crayfish and frogs. Mammals and waterfowl may occasionally be consumed in icy winters when water has frozen completely.
Animal Foods: birds; mammals; amphibians; fish; aquatic crustaceans
Primary Diet: carnivore (Piscivore )
Blakiston's fish owls occur only in select areas of northeast Asia. The enigmatic birds are found in eastern Siberia, northern China, North Korea, and northern Japan.
Biogeographic Regions: palearctic (Native )
Blakiston's fish owls require year-round open water to feed. They also need large trees for nesting cavities, and therefore are often found in riparian forests. Most of the surrounding woodlands are coniferous spruce and firs, or mixed deciduous forests with maple, ash and elm.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: forest
Other Habitat Features: riparian
No numbers were found in the literature, however, lifespan is thought to be similar to other fish owls found in the wild in Asia, approximately eight to fifteen years.
Bubo blakistonii looks much like brown fish owls (Bubo zeylonensis) of Asia. It is also one of the largest owl species in the world. Blakiston's fish owls have partially flattened feathers surrounding their faces (a feature of all owls) also known as 'facial disks' that give them a flat-faced appearance. They also have large, full-feathered ear tufts. Facial plumage is tan with black stripes and the brow of the eye has a thin row of white feathers. The wings and tail are a dark brown with yellowish stripes and the underside plumage is light brown with thin vertical black stripes.
The bill is long and curved and color ranges from grayish-blue to brown. The large claws are black and the tarsis are feathered in front. The iris is yellow. Bubo blakistoni is a large owl with a length of 60 to 71 cm and a wingspan of up to 2 m. Its weight ranges from 2.7 to 4 kg, and the males are smaller than the females.
Range mass: 2.7 to 4 kg.
Range length: 60 to 71 cm.
Range wingspan: 2 (high) m.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: female larger
No known predators were found in the literature.
Blakiston's fish owls tend to stay in pairs throughout the year. Male and female tend to be monogamous for many years.
Mating System: monogamous
Blakiston's fish owls do not breed every year; every two or three years is more typical. The young reach full size in 6 weeks and take up to 7 weeks to fledge. Fledgers still may remain in the area for up to a year and a half before they go off on their own. Once independent, the fish owl reaches sexual maturity at three years of age.
Blakiston's fish owls may select nest sites high up (2 to 18 m) in old-growth trees but have also been seen nesting on fallen trees on the forest floor. Laying begins in early spring and the pair typically has one to two eggs per two year interval. It takes about 35 days for eggs to hatch.
Breeding interval: On average, Blakiston's fish owls breed once every two years.
Breeding season: Blakiston's fish owls breed from early spring to summer.
Range eggs per season: 1 to 3.
Average time to hatching: 35 days.
Average fledging age: 50 weeks.
Average time to independence: 1.5 years.
Range age at sexual or reproductive maturity (female): 2 to 3 years.
Range age at sexual or reproductive maturity (male): 2 to 3 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
In Blakiston's fish owls, females perform egg incubation while males hunt for food. After the chicks have hatched, the female begins to join the male in night foraging. Investment in the young is high for this species; parents care for offspring up to two months and even share territories with valuable river access with them for up to a year after they are independent. Harsh conditions of the habitat may be cause for such high attention to young.
Parental Investment: altricial ; male parental care ; female parental care ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Male, Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male, Female); post-independence association with parents
