Blakiston's fish owl: The endangered giant of the east
- Published on : 28/05/2024
- by : Japan Experience
- Youtube
Blakiston's fish owl, the world's largest living owl species, is a rare bird found only in riparian forests of northeast Asia, including Japan, China, and the Russian Far East. Standing up to 75 cm tall with a 190 cm wingspan and weighing as much as 4.6 kg, the Blakiston's fish owl is a prodigious avian predator. However, this fascinating bird now faces extinction due to loss and fragmentation of its forest habitat, especially the big, old trees it requires for nesting. Blakiston's fish owl is currently listed as endangered by the IUCN, with only around 1,000 to 1,500 individuals estimated to remain in the wild.
Description and taxonomy of a rare giant
First described scientifically in 1884 by Henry Seebohm, Blakiston's fish owl is named after the English naturalist Thomas Blakiston, who collected the type specimen in Hokkaido, Japan. It is classified in the genus Ketupa along with three other fish owl species, although genetic evidence suggests Blakiston's is actually more closely related to the Eurasian eagle-owl (Bubo bubo). Two subspecies are recognized - B. b. blakistoni in Japan and the southern Kuril islands, and B. b. doerriesi on the Asian mainland.
The Blakiston's fish owl is a very large bird, even by eagle-owl standards. It has a barrel-shaped body, broad head with prominent ear tufts, massive yellow bill, and large, powerful talons. The upperparts are tawny brown barred and streaked with darker brown, while the underparts are paler with dark streaks. The facial disc is grayish-white with black border. Eye color is a piercing yellow.
A larger than life-size fish owl greets travelers arriving at Hokkaido's Kushiro Airport. They typically eat fish very much smaller in proportion than this one!
Unique adaptations for fishing and riverine life
Blakiston's fish owl possesses several physical and behavioral adaptations for catching and processing fish, its primary prey. The legs and toes are unfeathered, an unusual trait for an owl, with spiky scales on the undersides providing grip on slippery fish. The talons are exceptionally long and curved for snatching fish out of rivers and streams. Unusually for an owl, Blakiston's fish owl has a deep, resonant voice that travels well across water.
Blakiston's Fish Owl with typical, small fish prey. They usually consume prey head first.
This owl hunts primarily by waiting on a perch and watching for fish to come near the surface, then dropping down to snatch them with its talons. It also wades in shallow water to catch fish and can reportedly submerge fully to grab salmon. Other prey like frogs and small mammals are taken opportunistically. Blakiston's fish owls have been seen using fallen logs as "fishing platforms" and following the Japanese crested ibis to scavenge dead fish they leave behind.
The bare toes, massive roughened pads and long claws are the marks of a consummate predator.
Habitat needs: old-growth forests near unfrozen rivers
The Blakiston's fish owl inhabits old-growth forests along rivers, lakes, and coasts that don't completely freeze over, as it requires access to fish year-round. Its distribution is highly fragmented across this specialized riverine habitat. The species shows a strong preference for forests with large trees, snags, and fallen logs that provide cavities and platforms for nesting and hunting perches. Mature forests over 200 years old are considered optimal fish owl habitat.
In Russia, key tree species used by fish owls include Japanese poplar, chosenia, elm, Mongolian oak, and stone birch. Nest and roost site availability is a major limiting factor. Blakiston's fish owl pairs maintain large territories that can span over 15 km of river length.
Many of the rivers in their range freeze over in winter making fish inaccessible forcing Blakiston's Fish Owls to look elsewhere and for different prey.
Breeding biology and family life in fish owl pairs
Blakiston's fish owls form monogamous pair bonds and defend the same territory together year-round. Breeding occurs from February to May depending on latitude. The female lays 1-3 eggs (usually 2) in a nest cavity, rock crevice, or rarely an abandoned raptor stick nest. She incubates for about 35 days while the male delivers food.
The semi-altricial owlets hatch covered in white down. They are brooded by the female while the male continues providing fish, frogs, and occasionally mammals and birds. The young fledge at 35-40 days but remain with their parents for up to 2 years, an unusually long period of post-fledging care for owls. During salmon spawning season, fledglings beg loudly as their parents bring fish from the river throughout the day and night.
Its only in young owls, before the head is fully feathered, that the true size of the massive bill is visible. This downy fledgling Blakiston's Fish Owl already has the bright yellow eyes typical of the species.
Spiritual significance for the Ainu people of Japan
The Ainu people, the indigenous inhabitants of Hokkaido, consider the Blakiston's fish owl a kotan-kor-kamuy or "god that protects the village". Ainu folklore portrays the owl (known as kotan koru ekashi) as a messenger to the gods that informs them of human activities. The Ainu people have many stories about the fish owl, which they believe has the power to bring good fortune in fishing and hunting.
Even today, the Blakiston's fish owl is seen as an important cultural symbol in Hokkaido. Images and carvings of the owl are popular in Ainu artwork. The Ainu believe that careful stewardship is required for humans to maintain a harmonious relationship with the fish owl and the natural world it represents.
Threats to survival: logging, poaching, overfishing
The primary threats to the Blakiston's fish owl are logging of old-growth riverine forests, which destroys nesting and roosting sites, and development of river valleys for agriculture, roads, and settlements, which disturbs and fragments habitat. Dams and channelization of rivers degrades stream conditions for the owl's fish prey.
Overfishing, pollution, and climate change also impact salmon populations that fish owls depend on. In Russia, many owls drown in nets set illegally for salmon poaching. Owls are sometimes shot purposefully or hit by cars along roads at night. As human activity expands into wilderness areas, conflicts with fish owls increase.Survival of adult owls is critical as the species has a slow reproductive rate.
Conservation champions and their quest to save the species
Scientists and conservationists are working hard in Japan and Russia to study and protect the Blakiston's fish owl. In Hokkaido, nest boxes are being installed to provide more habitat as natural cavities in old trees become rare. Supplemental feeding programs provide fish to owls when rivers freeze in winter.
In Primorye, Russia, Jonathan Slaght of the Wildlife Conservation Society has spent years tracking fish owls, mapping their habitat, and working with logging companies to protect the most critical old-growth forest areas for fish owls. This has expanded protected habitat from 19% to over 60% of potential fish owl range in the region.
Researchers in both countries continue to monitor fish owl populations and work with government, industry, and local communities to reduce threats. Increasing public awareness and pride in this majestic bird helps build support for conservation. Recovery is a long-term process, but crucial gains are being made.
The author with an early prototype Blakiston's Fish Owl nest box, obtains a fish owl's view from a tree still far too young to have a suitable natural nesting cavity.
The fish owl's future: can this mysterious bird be pulled back from the brink?
With a world population hovering around 1,000 birds and habitat under continued pressure, the Blakiston's fish owl faces an uncertain future. But there are signs of hope. Collaborative conservation efforts by passionate scientists and concerned citizens in Russia and Japan have slowed the decline and demonstrate that recovery is possible with enough public and political will.
Much remains to be discovered about this elusive species that is more often heard than seen. Advances in GPS tracking, remote cameras, and genetic techniques are yielding new insights that can inform conservation strategies. By carefully managing old-growth forests, river habitats, and fish populations, we may yet secure a place in the wild for this spectacular owl to flourish as a vital part of Asian ecosystems and Japanese and Russian cultural heritage.
There is something undeniably charismatic and compelling about a bird as wild and rare as the Blakiston's fish owl. It captures our imagination and ignites our passion to protect what is left of the untamed landscapes it inhabits. The sound of its deep, booming duet echoing through the night forest is a symbol of nature's awe-inspiring mystery and majesty. The future of this species and the ecosystems it represents will depend on whether we can summon the determination to be worthy stewards of our shared planet. The fate of the fish owl will reflect our own.
For further information on wildlife in Japan, see Japan Nature. Learn more about these owls and conservation efforts at www.fishowls.com. Find books about nature and travel in Japan at our Books on Japan page.
