The tawny fish owl (''Ketupa flavipes'') is a
fish owl species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
in the
family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
known as
typical owl
The true owls or typical owls (family Strigidae) are one of the two generally accepted families of owls, the other being the barn owls (Tytonidae). This large family comprises 230 living or recently extinct species in 24 genera. The typical owl ...
s, Strigidae. It is native from southern Nepal to
Bangladesh
Bangladesh (}, ), officially the People's Republic of Bangladesh, is a country in South Asia. It is the eighth-most populous country in the world, with a population exceeding 165 million people in an area of . Bangladesh is among the mos ...
, Vietnam and
China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
. Due to its wide geographical distribution, it is listed as
Least Concern
A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...
on the
IUCN Red List
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...
.
[
]
Taxonomy
''Cultrunguis flavipes'' was the scientific name
In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...
proposed by Brian Houghton Hodgson
Brian Houghton Hodgson (1 February 1800 or more likely 1801 – 23 May 1894) was a pioneer naturalist and ethnologist working in India and Nepal where he was a British Resident. He described numerous species of birds and mammals from the Himala ...
in 1836 who described a yellow-footed fish owl from Nepal
Nepal (; ne, नेपाल ), formerly the Federal Democratic Republic of Nepal ( ne,
सङ्घीय लोकतान्त्रिक गणतन्त्र नेपाल ), is a landlocked country in South Asia. It is mai ...
.[
''Ketupa'' was proposed as ]generic
Generic or generics may refer to:
In business
* Generic term, a common name used for a range or class of similar things not protected by trademark
* Generic brand, a brand for a product that does not have an associated brand or trademark, other ...
name by René-Primevère Lesson in 1831 for fish owl species from Java
Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's List ...
and India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
.
Results of a phylogenetic
In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...
analysis of nine horned owl
The American (North and South America) horned owls and the Old World eagle-owls make up the genus ''Bubo'', at least as traditionally described. The genus name ''Bubo'' is Latin for the Eurasian eagle-owl.
This genus contains 19 species that ar ...
species indicate that ''Ketupa'' species form a monophyletic group
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
.
Description
Like other fish owls, the tawny fish owl has large ear tufts but they usually hang to the sides of the head and are distinctly messy and tousled looking. They have yellow eyes. Tawny fish owls have been described as the most "attractive" of the fish owls.[Hume, R. (1991). ''Owls of the world''. Running Press, Philadelphia, PA. 1991.] They tend to be an orangey-rufous color on the crown and upperparts, which are overlaid with broad, blackish markings on the central part of the feathers and spots of the same color as the reddish-brown feather edges. The scapulars are a dingy yellow color, forming a contrasting band which runs across the owl's shoulders. The flight and tail feathers are strongly barred dark brown and buffish. The facial disc is poorly defined but a sizeable off-white area on the eyebrows and forehead stands out. While buffy and brown fish owls are featherless on their legs and the Blakiston's fish owl
Blakiston's fish owl (''Bubo blakistoni''), the largest living species of owl, is a fish owl, a sub-group of eagle-owls which specialize in hunting in riparian areas. It is native to China, Japan, and the Russian Far East. This species is a par ...
(''B. blakistoni'') has totally feathered legs (the latter more like most ''Bubo''), the tawny fish owl has feathering over two-thirds of the tarsi. The legs below feathering are greenish-yellow with greyish-horn coloured talons. Beside the variability of the feathering of the legs, the buffy fish owl is most similar in plumage but is smaller and buff hued rather than orange-rufous hued. The brown fish owl is a much more solid brown color with distinct vermiculations below and no yellowish band across the back.
Compared to eagle owls of similar length, fish owls tend to be even shorter in tail length and even heavier in build, have relatively larger wings (the tawny and Blakiston's being particularly chunky in shape), have considerably longer legs, and have a rough texture to the bottom of their toes. At least the latter two features are clear adaptations to aid these owls in capturing fish. Diurnal raptors who feed largely on fish have similar, if not identical, rough texture under their toes, which helps these birds grasp slippery fish. Unlike diurnal raptors who capture fish such as the osprey (''Pandion haliaetus'') as compared to most terrestrial raptors, the fish owls have large, powerful, and curved talons and a longitudinal sharp keel sitting under the middle claw with all having sharp cutting edges that are very much like those of eagle owls. Also, unlike many fish-eating diurnal raptors, fish owl will not submerge any part of their body while hunting, preferring only to put their feet into the water, although fish owls will hunt on foot, wading into the shallows. Unlike most owls, the feathers of fish owls are not soft to the touch[ and they lack the comb and hair-like fringes to the primaries, which allow other owls to fly silently in order to ambush their prey. Due to the lack of these feather-specializations, fish owl wing beats make sounds. The lack of a deep facial disc in fish owls is another indication of the unimportance of sound relative to vision in these owls, as facial disc depth (as well as inner ear size) are directly related to how important sound is to an owl's hunting behavior. Similar adaptations, such as unwillingness to submerge beyond their legs and lack of sound-muffling feathers are also seen in the African fishing owls, which do not seem to be directly related.][ Tawny fish owls are around the same size as the brown fish owl in terms of linear dimensions. The tawny is long from bill to tail. However, studies have revealed the tawny is surprisingly rather heavier on average than the brown fish owl and, less surprising, is considerably heavier than an ]eagle owl
The American (North and South America) horned owls and the Old World eagle-owls make up the genus ''Bubo'', at least as traditionally described. The genus name ''Bubo'' is Latin for the Eurasian eagle-owl.
This genus contains 19 species that ar ...
of comparable length. Six adult tawny fish owls were found to weigh an average of , with a reported range of , and are thus one of the heaviest living owl species. Only the Blakiston's fish owl and a majority of races of Eurasian eagle owl
The Eurasian eagle-owl (''Bubo bubo'') is a species of eagle-owl that resides in much of Eurasia. It is also called the Uhu and it is occasionally abbreviated to just the eagle-owl in Europe. It is one of the largest species of owl, and females ...
(''B. bubo'') are heavier on average. The maximum (not average) weight of Verreaux's eagle owl
Verreaux's eagle-owl (''Bubo lacteus''), also commonly known as the milky eagle owl or giant eagle owl, is a member of the family Strigidae. This species is widespread in sub-Saharan Africa. A member of the genus ''Bubo'', it is the largest Afric ...
s (''B. lacteus'') and snowy owl
The snowy owl (''Bubo scandiacus''), also known as the polar owl, the white owl and the Arctic owl, is a large, white owl of the true owl family. Snowy owls are native to the Arctic regions of both North America and the Palearctic, breeding mos ...
s (''B. scandiacus'') are also higher but those species have far larger sample sizes of body mass.[Dunning, J.B. (2008). ''CRC Handbook of Avian Body Masses, 2nd Edition''. CRC Press, .] In terms of standard measurements, the wing chord is , the tail
The tail is the section at the rear end of certain kinds of animals’ bodies; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, r ...
is , the tarsus is and the bill
Bill(s) may refer to:
Common meanings
* Banknote, paper cash (especially in the United States)
* Bill (law), a proposed law put before a legislature
* Invoice, commercial document issued by a seller to a buyer
* Bill, a bird or animal's beak
Plac ...
is . Compared to the brown fish owl, the tawny averages of similar tail length, is larger in size by average wing length and bill size and slightly smaller in tarsal length.[Weick, F. (2007). ''Owls (Strigiformes): annotated and illustrated checklist''. Springer.]
Distribution and habitat
The tawny fish owl lives in subtropical
The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Geographical z ...
to temperate
In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...
forest
A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...
s in southern Nepal
Nepal (; ne, नेपाल ), formerly the Federal Democratic Republic of Nepal ( ne,
सङ्घीय लोकतान्त्रिक गणतन्त्र नेपाल ), is a landlocked country in South Asia. It is mai ...
, northern India
North India is a loosely defined region consisting of the northern part of India. The dominant geographical features of North India are the Indo-Gangetic Plain and the Himalayas, which demarcate the region from the Tibetan Plateau and Central ...
, Bangladesh
Bangladesh (}, ), officially the People's Republic of Bangladesh, is a country in South Asia. It is the eighth-most populous country in the world, with a population exceeding 165 million people in an area of . Bangladesh is among the mos ...
, Bhutan
Bhutan (; dz, འབྲུག་ཡུལ་, Druk Yul ), officially the Kingdom of Bhutan,), is a landlocked country in South Asia. It is situated in the Eastern Himalayas, between China in the north and India in the south. A mountainous ...
, China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
, Laos
Laos (, ''Lāo'' )), officially the Lao People's Democratic Republic ( Lao: ສາທາລະນະລັດ ປະຊາທິປະໄຕ ປະຊາຊົນລາວ, French: République démocratique populaire lao), is a socialist ...
, Myanmar
Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John C. Wells, Joh ...
, Taiwan
Taiwan, officially the Republic of China (ROC), is a country in East Asia, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the nort ...
, and Vietnam
Vietnam or Viet Nam ( vi, Việt Nam, ), officially the Socialist Republic of Vietnam,., group="n" is a country in Southeast Asia, at the eastern edge of mainland Southeast Asia, with an area of and population of 96 million, making i ...
. It inhabits the Himalayan foothills from Kashmir
Kashmir () is the northernmost geographical region of the Indian subcontinent. Until the mid-19th century, the term "Kashmir" denoted only the Kashmir Valley between the Great Himalayas and the Pir Panjal Range. Today, the term encompas ...
and Garhwal Garhwal may refer to the following topics associated with Uttarakhand, India:
Places
*Garhwal Himalaya, a sub-range of the Himalayas
*Garhwal Kingdom, a former kingdom
* Garhwal District (British Garhwal), a former district of British India
*Gar ...
east to the mountains in Laos, Vietnam and southern China up to Chekiang and Anhwei
Anhui , (; formerly romanized as Anhwei) is a landlocked province of the People's Republic of China, part of the East China region. Its provincial capital and largest city is Hefei. The province is located across the basins of the Yangtze River ...
. It requires forest tracts with mountain streams. In areas such as Darjeeling
Darjeeling (, , ) is a town and municipality in the northernmost region of the Indian state of West Bengal. Located in the Eastern Himalayas, it has an average elevation of . To the west of Darjeeling lies the easternmost province of Nepal, ...
and Nepal, it lives at elevations of . Its range partly overlaps with the one of brown fish owl
The brown fish owl (''Ketupa zeylonensis'') is a fish owl species in the family known as typical owls, Strigidae. It is native from Turkey to South and Southeast Asia. Due its wide distribution it is listed as Least Concern on the IUCN Red List. ...
(''K. zeylonensis'') in Laos and Vietnam, where it prefers fast flowing waters in remote wilderness with little to no disturbance.[
]
Behaviour and ecology
The tawny fish owl's territorial call is a deep ''whoo-hoo''. It also makes a cat-like ''meow''.
Four tawny fish owls were equipped with radio transmitters
In electronics and telecommunications, a radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna. The transmitter itself generates a radio frequency alternating current, which is applied to the ...
in Taiwan and monitored from October 1994 to July 1996. They were mainly nocturnal, left their day-time roosts around sunset and returned before sunrise. They were most active moving and foraging during twilight, and moved up to in an hour. They moved more frequently in the cold season. In summer, breeding owls showed some daytime activity, consisting mainly of preening
Preening is a found in birds that involves the use of the beak to position feathers, interlock feather that have become separated, clean plumage, and keep ectoparasites in check. Feathers contribute significantly to a bird's insulation, waterp ...
. They also hunted during the day when feeding their fledglings.
Each owl used up to 17 different roosting
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...
sites that were all located in old-growth forest away from a stream. In the cold season, they roosted closer to streams, but also moved to uphill roosting sites in the warmer months. They avoided disturbed habitat like grassland, agricultural land and the vicinity of villages.
The tawny fish owl is at least partially diurnal in activity, with daytime activity mainly occurring in the late afternoon and they may be seen actively hunting before nightfall especially on cloudy days. However, before the afternoon they tend to be sluggish during the day.[Voous, K.H. 1988. ''Owls of the Northern Hemisphere''. The MIT Press, 0262220350.] If disturbed or threatened, these owls tend to sit tight and not take flight. Like most owls, they usually choose inconspicuous perches during the day to avoid detection.[ The tawny fish owl has been described as the "most powerful and savage" of the three smaller fish owl species.][ The pellets of tawny fish owls in Taiwan were found on rocks, under perching and daytime roosts. They contained remains of Taiwan ]mitten crab
The Chinese mitten crab ('; , "big sluice crab"), also known as the Shanghai hairy crab (, p ''Shànghǎi máoxiè''), is a medium-sized burrowing crab that is named for its furry claws, which resemble mittens. It is native to river ...
('' Eriocheir formosa''), tip-nosed frog (''Odorrana swinhoana
''Odorrana swinhoana'' is a species of frog in the family Ranidae. It is endemic to Taiwan and widely distributed in hilly areas below . It is named for Robert Swinhoe, a British naturalist and diplomat. Its common names include Swinhoe's brown ...
''), brown tree frog ('' Buergeria robusta''), Asiatic toad
The Asiatic toad or Chusan Island toad (''Bufo gargarizans'') is a species of toad endemic to East Asia. The species was previously classified as ''Bufo bufo gargarizans'', a subspecies of the common toad.
Distribution and habitat
It is commo ...
(''Bufo gargarizans''), freshwater crab
Around 1,300 species of freshwater crabs are distributed throughout the tropics and subtropics, divided among eight families. They show direct development and maternal care of a small number of offspring, in contrast to marine crabs, which relea ...
s, shrimps and fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...
. They took toads considerably more regularly than other frog species, although far less abundant in number in the stream and wetlands, due to their larger sizes.
They usually hunt by swooping down to the water, capture fish from the surface and are reportedly surprisingly active in their hunting style and are not dissimilar in the hunting methods to those used by diurnal fish-hunting raptors such as fish eagles, sea eagle
A sea eagle or fish eagle (also called erne or ern, mostly in reference to the white-tailed eagle) is any of the birds of prey in the genus ''Haliaeetus'' in the bird of prey family Accipitridae.
Taxonomy and evolution
The genus ''Haliaeetus'' ...
s and osprey
The osprey (''Pandion haliaetus''), , also called sea hawk, river hawk, and fish hawk, is a diurnal, fish-eating bird of prey with a cosmopolitan range. It is a large raptor reaching more than in length and across the wings. It is brown o ...
s. More terrestrial prey is by no means avoided though and the species may also hunt toad
Toad is a common name for certain frogs, especially of the family Bufonidae, that are characterized by dry, leathery skin, short legs, and large bumps covering the parotoid glands.
A distinction between frogs and toads is not made in scientif ...
s, lizard
Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia alt ...
s, snake
Snakes are elongated, Limbless vertebrate, limbless, carnivore, carnivorous reptiles of the suborder Serpentes . Like all other Squamata, squamates, snakes are ectothermic, amniote vertebrates covered in overlapping Scale (zoology), scales. Ma ...
s, and small mammal
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
s such as mole
Mole (or Molé) may refer to:
Animals
* Mole (animal) or "true mole", mammals in the family Talpidae, found in Eurasia and North America
* Golden moles, southern African mammals in the family Chrysochloridae, similar to but unrelated to Talpida ...
s, and particularly rodents
Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are nat ...
, with one of the few mammalian prey recorded semi-regularly being bamboo rat
The bamboo rats are four species of rodents of the subfamily Rhizomyinae. They are the sole living representatives of the tribe Rhizomyini. All are found in South Asia, Southeast Asia and East Asia.
The species are:
*The Chinese bamboo rat, '' ...
s (''Rhizomys
''Rhizomys'', also known as bamboo rat, is a genus of rodents in the family Spalacidae. ''Rhizomys'' are all stocky burrowers with short, naked tails, and contains the following species:
* Hoary bamboo rat (''R. pruinosus'')
* Chinese bamboo ...
''). A small Malayan porcupine
The Malayan porcupine or Himalayan porcupine (''Hystrix brachyura'') is a species of rodent in the family Hystricidae. Three subspecies are extant in South and Southeast Asia.
Geographical distribution
The Malayan porcupine ranges from Nepal th ...
(''Hystrix brachyura'') has also been reported amongst their prey. It also prey on birds including Mandarin duck
The mandarin duck (''Aix galericulata'') is a perching duck species native to the East Palearctic. It is medium-sized, at long with a wingspan. It is closely related to the North American wood duck, the only other member of the genus ''Aix''. ...
s (''Aix galericulata'') in Taiwan and has overtaken large ground birds such junglefowl
Junglefowl are the only four living species of bird from the genus ''Gallus'' in the bird order Galliformes, and occur in parts of South and Southeast Asia. They diverged from their common ancestor about 4–6 million years ago.
Although origin ...
(''Gallus'' ssp.), pheasant
Pheasants ( ) are birds of several genera within the family (biology), family Phasianidae in the order (biology), order Galliformes. Although they can be found all over the world in introduced (and captive) populations, the pheasant genera na ...
s and eared pheasants, the latter sometimes weighing more than . Tawny fish owls tend to be sparsely distributed and frequently live in riparian zones of in length.[
Tawny fish owls are highly solitary and territorial as are a majority of owls. The breeding season is November to February in ]India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
and December to February in Assam
Assam (; ) is a state in northeastern India, south of the eastern Himalayas along the Brahmaputra and Barak River valleys. Assam covers an area of . The state is bordered by Bhutan and Arunachal Pradesh to the north; Nagaland and Manipur ...
. Nest locations found have included large holes in river banks, caves in cliffs and the fork or crotch of a large tree. As in all owls, tawny fish owls do not build a nest so merely lay their eggs on the bare ground of whatever surface they use. They also not infrequently nest in abandoned nests built by Pallas's fish eagle
Pallas's fish eagle (''Haliaeetus leucoryphus''), also known as Pallas's sea eagle or band-tailed fish eagle, is a large, brownish sea eagle. It breeds in the east Palearctic in Kazakhstan, Russia, Tajikistan, Turkmenistan, Uzbekistan, Mongolia, C ...
s (''Haliaeetus leucoryphus''). Usually two eggs are laid but sometimes only one is. The eggs can range in size from x , with an average of , and are similar in size to those of the brown fish owl. Greater details of the reproductive biology are not currently known although are presumed to basically be similar to those of other fish owls.[
]
References
External links
{{Taxonbar, from=Q1270506
tawny fish owl
The tawny fish owl (''Ketupa flavipes'') is a fish owl species in the family known as typical owls, Strigidae. It is native from southern Nepal to Bangladesh, Vietnam and China. Due to its wide geographical distribution, it is listed as Least Co ...
Birds of North India
Birds of Eastern Himalaya
Birds of China
Birds of Yunnan
Birds of Hong Kong
Birds of Taiwan
Birds of Laos
Birds of Vietnam
tawny fish owl
The tawny fish owl (''Ketupa flavipes'') is a fish owl species in the family known as typical owls, Strigidae. It is native from southern Nepal to Bangladesh, Vietnam and China. Due to its wide geographical distribution, it is listed as Least Co ...
Taxonomy articles created by Polbot