Ural Owl
Ezo Fukurou
Hokkaido, Japan
Somewhere deep within the Kushiro-shitsugen National Park, in the Kottaro wetlands along the banks of the Kushiro, I found the elusive Ural Owl. Named for the Ural Mountains of Russia which is part of their natural range and where the first specimen was collected, these owls are threatened by humans eliminating the hollow trees they nest in.
The Ural Owl that lives in Hokkaido is actually a subspecies of the Ural Owl that Japanese often call the Ezo Fukurou (S. u. japonica). The Japanese used the name Ezo or Ezochi to refer to the island of Hokkaido until they renamed it in the mid-19th century, and Fukurou is the generic Japanese word for owl. "Ezo" appears in the names of many species and subspecies of wildlife that live in Hokkaido - for example my earlier blog on the Ezo Red Fox. Though Fukurou is the word for owl in Japanese, strictly speaking, Fukurou is only the Ural Owl which, in the case of our region of Hokkaido, is only one of 10 species of the Owl family (Fukurou-ka) that live here. We also had the good fortune to meet the largest living species of owl as well, the endangered Shima-fukurou (Blakiston's Fish-Owl).
Also known as Ural Wood Owls - they are medium-large, nocturnal owls found in Europe and northern Asia. Like most Strix species, it has a broad, rounded head with a correspondingly round facial disc, barring a tiny V-shaped indentation. The Ural owl has, for an owl, an exceptionally long tail that bears a wedge-shaped tip. In colour, it tends to be a plain pale greyish-brown to whitish overall (with more detailed description of their variation under subspecies), with a slightly darker grey-brown to brown back and mantle with contrasting whitish markings. The underparts are pale cream-ochre to grey-brown and are boldly (though sometimes more subtly) overlaid with dark brown streaking, without crossbars. Many variations are known in overall plumage colour both at the subspecies level and the individual level. However, the Ural owl usually appears as a rather pale grey-brown owl with distinct streaking below. Light and dark morphs are known to occur, with the light form being more common.
Distribution & Habitat
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (extent of occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Strix uralensis Distribution Map & the Hokkaido location
Ural Owls occur in Europe and Asia, from Sakhalin, Japan and Korea in the east to Scandinavia in the west. The southern border follows the southern delimitation of the taiga (boreal forest). They are associated with loose, mature, mixed forests and favor moist rather than dry areas. Even though they are still common throughout much of their range, their numbers have been declining in areas where hollow and broken trees were removed from the forest, reducing their nesting habitat.
Ural owls are often considered nocturnal with peaks of activity at dusk and just before dawn. However, since they mainly live in the taiga zone where very long summer days are the norm against extensive dark during the winter, Ural owls are often fully active during daylight hours during the warmer months, while brooding young. Presumably during winter, they are mostly active during the night. Thus, the species may be more correctly classified as cathemeral as is much of their main prey. During the day, Ural owls may take rests on a roost, which is most typically a branch close to the trunk of a tree or in dense foliage. They are highly territorial and residential birds that tend to stay on the same home range throughout the year. Territories are generally maintained with songs, most often uttered by the male of the resident pair. Ural owls do most of their hunting from a perch. They usually prefer prey that comes into open spots of the forest rather than those that frequent the forest floor. These birds never attack prey from an active flight, instead nearly always dropping down on it directly from their perch. Ural owls have a wide range of calls; however, despite that, these birds are generally very quiet and may not vocalize even at peak times for perhaps up to nearly 2 days.
The song of the male is a deep rhythmic series of notes, variously transcribed as 'wihu huw-huhuwo or huow-huow-huow'. The female has a similar but hoarser and slightly higher pitched song, giving it a more "barking" quality. Not infrequently, Ural owls will duet during courtship. In addition, a deep, hoarse heron-like 'kuwat' or 'korrwick' is probably used as a contact call. Males sing from different perches to claim their territory and to can be heard courting mates with their song. Their loud territorial calls can be heard for up to 1.2 miles or 2 kilometers and are described as a soft, deep 'wo-ho….. woho uhwo-ho'. They also deliver unmistakable yapping 'wau - wau' sounds. The pair mates for life and inhabits the same territory for years. The Ural owl is nocturnal, with peaks of activity at dawn and dusk and roost during the day in the cover of trees.
The following video is the owl I was able to document, tucked away in the hollow of a dead tree and not very active while we were there so I had to make the most of what I could see standing almost waist deep in the precariously balanced snow drifts. Filmed and photographed using the Canon 1Dx Mark ii + EF 600 f/4 L IS iii with and without both the extenders used intermittently.
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Ural owls are carnivores and mostly prefer to take small prey, especially small mammals. Their diet includes various species of rodent, shrews, moles, any variety of small mammal, to the size of hares, as well as variable numbers of birds, amphibians and invertebrates. Rarely will they take reptiles and fish.
Fun Facts:
In other languages, the Ural owl is referred to as Slaguggla or “attacking owl” in Swedish, Habichtskauz or “goshawk-owl” in German and as the “long-tailed owl” in Russian.
The ears of the Ural owl are quite large. In fact their ears are amongst the largest recorded in owls. In combination with their large ears, the well-developed facial disc shows how important sound is to this and other owls who hunt in boreal zones.
It was reported that in total Ural owls utter about nine different calls. Their alarm call is typically delivered during territorial rounds and can be heard at up to 1,500 m (4,900 ft) away. Ural owls also have a particularly menacing bill-snapping display which they use when feeling threatened.
Ural owls are fairly powerful hunters. They take more than 200 prey species, of which more than 80 are mammals.
Sources
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