White-tailed Eagle
Haliaeetus albicilla
Hokkaido, Japan
The White-tailed eagle (Haliaeetus albicilla) is one of the largest living birds of prey. It is the largest of the dozen species of eagle found in Europe and the largest eagle across its distribution, excluding the Russian Far East and (during the winter) Hokkaido, Japan, where it co-exists with its larger cousin, the Steller's Sea Eagle. I had the opportunity to observe and document these magnificent eagles against a backdrop of extreme landscapes exposed to incredibly harsh climate during the winter off the coast of Rausu, Hokkaido.
The white-tailed eagle is a species of sea eagle widely distributed across temperate Eurasia. Like all eagles, it is a member of the family Accipitridae (or accipitrids) which includes other diurnal raptors such as hawks, kites, and harriers. One of up to eleven members in the genus Haliaeetus, which are commonly called sea eagles, it is also referred to as the white-tailed sea-eagle. Sometimes, it is known as the ern or erne (depending on spelling by sources), gray sea eagle and Eurasian sea eagle.
Our journey to the ice began well before first light from Rausu-chō, a town located in Nemuro Subprefecture, Hokkaidō, Japan. We took an ice-breaker and ventured out into the drift ice. The word "Rausu" originates from the Ainu word Raushi, roughly meaning "Low-land" or "Place of men with beast-like spirit". It was about 16 or 20 degrees celsius below freezing and the wind chill bit through all the layers we had on. But once we saw the eagles - the Steller’s and the White-tailed - all was forgotten. In the video I have here the engines of the ice-breakers can be heard in the background trying to hold their ground in the moving and cracking ice.
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The Stellar’s Sea Eagle taking off against the backdrop of the rising sun has become my logo and both the Stellar’s & the White-tailed Eagle have been published. Click the button to view them.
The Sea of Okhotsk
The Sea of Okhotsk (pronounced Okhótskoye móre in Russian and Ohōtsuku-kai in Japanese) is a marginal sea of the western Pacific Ocean. It is located between Russia's Kamchatka Peninsula on the east, the Kuril Islands on the southeast, Japan's island of Hokkaido on the south, the island of Sakhalin along the west, and a stretch of eastern Siberian coast along the west and north. The northeast corner is the Shelikhov Gulf. The sea is named after the Okhota river, which in turn named after the Even word окат (okat) meaning "river".
The Sea of Okhotsk covers an area of 1,583,000 km², with a mean depth of 859 metres (2,818 ft) and a maximum depth of 3,372 metres (11,063 ft). It is connected to the Sea of Japan on either side of Sakhalin: on the west through the Sakhalin Gulf and the Gulf of Tartary; on the south through the La Pérouse Strait.
In winter, navigation on the Sea of Okhotsk is impeded by ice floes. Ice floes form due to the large amount of freshwater from the Amur River, lowering the salinity of upper levels, often raising the freezing point of the sea surface. The distribution and thickness of ice floes depends on many factors: the location, the time of year, water currents, and the sea temperatures.
Cold air from Siberia forms sea ice in the northwestern Sea of Okhotsk. As the ice forms it expels salt into the deeper layers. This heavy water flows east toward the Pacific carrying oxygen and nutrients, supporting abundant sea life. The Sea of Okhotsk has warmed in some places by as much as 3 degrees Celsius since preindustrial times, three times faster than the global mean. Warming inhibits the formation of sea ice and also drives fish populations north. The salmon catch on the northern Japanese coast has fallen 70% in the last 15 years, while the Russian chum salmon catch has quadrupled.
With the exception of Hokkaido, one of the Japanese home islands, the sea is surrounded on all sides by territory administered by the Russian Federation. South Sakhalin and the Kuril islands were administered by Japan until 1945. Japan claims the southern Kuril islands and refers to them as "northern territories".
The Okhotsk people and the later Ainu culture, a coastal fishing and hunter-gatherer people, were located around the lands surrounding the Sea of Okhotsk, as well as in northern Japan.
White-tailed Eagle Range
In winter, the extreme climate and geography mean the Sea of Okhotsk defies its position (at about the same latitude as France’s Mediterranean coast) and freezes. This drift ice attracts the White-tailed Eagles & Steller’s Sea Eagles and they winter on or close to the sea ice, a curiosity that has attracted bird lovers and photographers for many years.
White-tailed Eagle
The white-tailed eagle is a member of the genus Haliaeetus, a monophylic group comprising 11 living species, including the closely related Ichthyophaga fish eagles which may or may not be part of a separate genus. The latter group, comprised by the lesser (Haliaeetus humilis) and the grey-headed fish eagle (Haliaeetus ichthyaetus), differ mostly in life history, being more fully devoted to fish eating & habituating wooded areas, especially in mountainous areas. In appearance the two Ichthyaetus are slenderer, longer tailed and more uniform and grey in colour than typical sea eagles. This species pair may not be genetically distinct enough to warrant division into separate genera.
The white-tailed eagle itself forms a species pair with the bald eagle. These diverged from other sea eagles at the beginning of the early Miocene (c. 10 mya) at the latest, possibly (if the most ancient fossil record is correctly assigned to this genus) as early as the early or middle Oligocene, about 28 mya. A recent genetic study of mitochondrial DNA is consistent with this idea. Greenlandic white-tailed eagles (proposed as H. a. groenlandicus) form, on evolutionary time scales, a relatively recently founded population that has not yet accumulated many unique genetic characteristics and may not strictly fulfil the distinction of a subspecies. However, the population appears to be demographically isolated and deserves special protection.
The White-tailed Eagle, while found across a very wide range, today breeding as far west as Greenland and Iceland across to as far east as Hokkaido, Japan, are often scarce and very spottily distributed as a nesting species, mainly due to human activities. These have included habitat alterations and destruction of wetlands, about a hundred years of systematic persecution by humans (from the early 1800s to around World War II) followed by inadvertent poisonings and epidemics of nesting failures due to various manmade chemical pesticides and organic compounds, which have threatened eagles since roughly the 1950s and continue to be a potential concern. Due to this, the white-tailed eagle was considered endangered or extinct in several countries. However, some populations have recovered well due to some governmental protections and dedicated conservationists and naturalists protecting habitats and nesting sites and partially regulating poaching and pesticide usage, as well as careful reintroductions into parts of their former range.
White-tailed eagles usually live most of the year near large bodies of open water, including coastal saltwater areas and inland freshwater lakes, wetlands, bogs and rivers. It requires old-growth trees or ample sea cliffs for nesting, and an abundant food supply of fish and birds (largely water birds) amongst nearly any other available prey. Both a powerful apex predator and an opportunistic scavenger, it is considered a close cousin of the bald eagle (Haliaeetus leucocephalus), which occupies a similar niche in North America.
Like the third large northern species, Steller's sea eagle (Haliaeetus pelagicus), adults have yellow feet, beaks and eyes. Another species, likely intermediate between the white-tailed, bald and Steller's sea eagles and the Ichthyophaga type fish eagles, is the Pallas's fish eagle (Haliaeetus leucoryphus), which in life history seems to range farther from water and to higher elevations than the three northern species normally do. Due to the similar dietary and nesting habits of sea eagles, they are mostly allopatric in distribution as competition can be considerable between these eagles.
The only country in which the white-tailed eagle is found over a continuous and extremely large area is Russia. The species is found very broadly everywhere in Russia from European Russia in the west to the Bering Sea in the east, only being fully absent as a nester as far as is known from the high Arctic regions and a section bordering westernmost Kazakhstan, although it breeds to south of this in the Russian coastal part of the Caspian Sea. Their northern limits occur in Russia to the Ob river to 70 degrees north at the mouth of the Yenisei River and on the Gyda and Yamal Peninsulas, to the Kolyma, Indigirka and Lena rivers to above 72 degrees north, even to 75 degrees north on the Taymyr Peninsula. They are said to be common around the White Sea, reportedly even the most abundant bird of prey locally and found both on coasts and inland lakes, although breeding rates are low due to the frigid weather. From Russia, breeding populations spill somewhat into northernmost Mongolia, extreme northwestern China and northern North Korea. The white-tailed eagle also breeds on Sakhalin Island, the Kuril Islands and Hokkaido, the northernmost island of Japan.
Overall, nearly 70 species of fish are known to be taken from throughout the white-tailed eagle's range. White-tailed eagles can hunt fish in fresh or saltwater as well as those that prefer brackish water areas. However, they are basically restricted to taking fish in extremely shallow water, often by preference in water less than 1 m (3.3 ft) deep. Ideal fishing areas can be found in areas such as the Baltic Sea, where low coasts and archipelagos often have relatively shallow water. While healthy, large fish are often taken as well, white-tailed eagles often take out sickly, injured or already dead fish. In some cases, the fish prey will float to the surface when infected by fish tapeworm, as is often the case with some fish families such as carp. Fish are also caught after being battered, injured and killed at power plants, from large-scale fishing nets or are taken directly from human fishermen.
This fact was especially important to nesting eagles in Hokkaido, Japan where 54% of 533 prey items were fish, led by the 800 g (1.8 lb) Alaska pollock (Gadus chalcogrammus). In different studies of the Danube Delta of Romania, from 44.6% to 79% of the diet was comprised by fish, led by the common carp (Cyprinus carpio) and Prussian carp (Carassius gibelio). In the Kostomuksha Nature Reserve of Russia, fish were strongly dominant in food remains, making 80% of the known diet.
White-tailed eagles are known to prey on about 170 species of bird, the most diverse group in their prey spectrum. While hunting birds, this massive, relatively slow-flying eagle requires an element of surprise, with often a tactful use of cover or bright sunlight upon the approach from a nearby perch. The most widely recorded avian prey species and, second most widely recorded prey species behind the pike, is the 1.14 kg (2.5 lb) mallard, due to its circumpolar range and commonality in many wetlands areas. However, as aforementioned, healthy mallards are difficult for white-tailed eagles due to their tendency to fly at first sign of danger. However, exploiting the mallard's flightlessness during eclipse plumage may result in eagles hunting them intensely only in late summer. Due to this mallards are usually a secondary prey species year around.
The first glimpse across the drift ice in the land of the rising sun.
As the largest eagle in the majority of its distribution, the white-tailed eagle is an apex predator in its range. In some areas it may compete with other large raptors, especially golden eagles. Relations between these two species are complex and variable. White-tailed eagles may live alongside a wide range of other large raptors, but other eagles are considerably different in dietary and habitat preferences, so there is almost no competitive effect. For example, in Kazakhstan, white-tailed eagles were recorded to nest in proximity to golden eagles, Eastern Imperial Eagles (Aquila heliaca) and Steppe Eagles (Aquila nipalensis) and all four eagles appear almost entirely indifferent to the presence of the other species, given their considerable partitioning in diet and habitat preferences. More significantly than the Aquila species, the white-tailed eagle seemed to have no issue nesting within a few hundred metres of the other eagles. Read about my other eagles.
The only other Haliaeetus to live broadly alongside white-tailed eagles are Steller's sea eagles. Being larger and heavier, the Steller's is often characterised as a more powerful predator. Nonetheless, studies of the species ecologies show that the Steller's is a more restricted feeder on salmonids & that the Steller's tended to defend a smaller home range area than white-tailed eagles do in the Russian Far East. However, the Steller's appeared to be more flexible in readily switching nest sites between trees and rocky areas, whereas white-tailed eagles of this area exclusively nested in trees. Both species seemed to avoid active territories of the other but little direct conflict during breeding was detected. Although the Steller's sea eagle may be somewhat favoured in wintertime food conflicts given its sometimes considerably larger size, both it and the white-tailed eagles have been observed to win conflicts over fish, with golden eagles sometimes entering the fray and sometimes losing or winning conflicts.
The white-tailed eagle formerly bred over much wider area, extending west to much of western Europe & perhaps south almost continuously in that region to the Mediterranean. From the 19th century, the species underwent a huge, well-documented decline. Ultimately the white-tailed eagle was almost extinct in Europe, extirpated from all but Fennoscandia (mainly remaining in Norway) and some sparse patches of eastern Europe. They were extinct in the entire British Isles by the early 1900s. At one time, the white-tailed eagle bred down to Egypt in Africa, particularly around Lake Manzala with individuals wandering rarely to Algeria and Tunisia. It is likely that habitat degradation and drying conditions caused the extirpation of the species as all but a vagrant in Egypt. Two pairs that nested in the Jordan Valley ceased to breed, apparently due to agricultural chemicals, in the early 1950s. The species also once bred in northern Syria but is not found reliably there even in winter in modern times.
Densities of white-tailed eagles have greatly increased in some parts of the range due to conservation efforts. Some threats still remain, notably illegal persecution by game bird shooting and egg thieves in Scotland. In prime habitat in north Europe, distance between breeding pairs can be only 4 km (2.5 mi) (even as little as 1–2 km [0.6–1.2 mi] locally) such as in Norway, density at one Polish forest were even reported at 6–7 in each square kilometer. In the late 1990s, it was estimated that Russia held as many as 5,000 to 7,000 pairs, with around 175 pairs in Greenland and almost 3,500 pairs in Europe, led by Norway (1,500+ pairs), European Russia (900–1,100), Poland (180–240), Germany (140–150) and Sweden (100–150). The largest population in Europe is found along the coast of Norway. Over 500 winter in Japan, mainly Hokkaido, but this island may have only 20 pairs breeding. Strong increases were recorded in Croatia, with no less than 135 breeding pairs estimated in Croatia by 2009, up from only 25–30 in 2007.
With that said let’s look at these magnificent eagles surviving in the extreme climate of the Sea of Okhotsk off the island of Hokkaido, Japan.
Some interesting facts of the White-tailed Eagles
White-tailed Eagles are closely related to Bald Eagles. They hold the same niche in the ecology of Eurasia that the Bald Eagle holds in North America.
On average the White-tailed Eagle has the largest wingspan of any Eagle.
The largest population of White-tailed Eagles in Europe is found along the coast of Norway.
A White-tailed Eagle’s territory can range as far as 70km. They’re almost always located around bodies of water.
A White-tailed Eagle appears in Germany’s coat-of-arms and is Germany’s national bird.
White-tailed Eagles are the largest Eagles in Europe.
The White-tailed Eagles found in Europe are mainly sedentary, while the White-tailed Eagles found in Russia and northern Asia are migratory.
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The White-tailed Eagle on the drift ice off the coast of Rausu-chō, feeding in close proximity to our icebreaker.
Among the spectacular birds of Hokkaido are two eagles - the Steller's Sea Eagle and the White-tailed Eagle. This is a record of the two species off the coast of Rausu, on drift ice floating in the Sea of Okhotsk in sub zero temperatures, in February 2020.
The Steller's Sea Eagle is one of the world's largest birds of prey. It can weigh up to ten kilograms which is half a kilogram heavier than the famed Harpy Eagle of South America. Growing to a meter in length, its wingspan can reach over two meters. Compared to its length, it has a relatively short, diamond-shaped white tail. Mostly dark brown, this eagle has splashes of white on its body and most notably a long patch on each shoulder.
Its most remarkable feature is its large and bulb-shaped orange beak. One would not want to be on the receiving end of either the beak or their massive talons. The bird catches fish from the sea and hunts smaller birds including all manners of water fowl and gulls.
Steller's Sea Eagles live most of the year in northeastern Asia, particularly the Kamchatka Peninsula, where they breed. They migrate to northern Japan during the winter and feed off the fish of surrounding waters.
The White-tailed Eagle, on the other hand, makes Hokkaido its year-round home. It, too, is a large eagle with a weight of up to seven kilograms, length of slightly less than a meter, and wingspan similar to that of the Steller's Sea Eagle. The adults are dirty grey in colour with a pronounced white band seen on its tail while in flight, much like our Pallas's Fish Eagles. The younger eagles are coloured more rust and brown.
For both these eagles, females are larger and heavier than males. This difference allows males and females to target different sets of prey, thus reducing the area they must cover to feed themselves.
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