Pallas's Sea Eagle
Encyclopedia
Pallas's Fish Eagle also known as Pallas's Sea Eagle or Band-Tailed Fish Eagle, is a large, brownish sea-eagle
. It breeds in Central Asia
, between the Caspian Sea
and the Yellow Sea
, from Kazakhstan
and Mongolia
to the Himalayas
, Bangladesh
and northern India
. It is partially migratory
, with central Asian birds wintering among the southern Asian birds in northern India, and also further west to the Persian Gulf
.
of 180–215 cm (70.9–84.6 in). Females, at 2.1-3.7 kg (4.6-8.2 lbs), are slightly larger than males, at 2-3.3 kg (4.4-7.3 lbs).
Its diet consists primarily of large freshwater fish.
of its genus
, it has no close living relatives. mtDNA cytochrome b
sequence
data is unable to reliably suggest a phylogenetic place for it among the sea-eagles. However, some information can be drawn from the molecular data, and especially from morphology
and biogeography
:
This species retains the ancestral dark eye, bill
, and talon
s of the first sea-eagles, shared with the older tropical
lineage. It is peculiar insofar as it has a black band at the end of the tail in adult birds, similar to juvenile Madagascar Fish Eagle
s (which look like a smaller, darker version of this bird, but are not very closely related). Its distribution indicates that this species evolved fairly independently of other sea-eagle lineages, but the molecular data tentatively suggests it is possibly closer to the Holarctic
species.
It diverged from its common ancestor with other species soon after the Holarctic and the tropical lineages split. Dependent on the interpretation of a possible Early Oligocene
sea-eagle fossil from Egypt
, this happened either at the very start or the end of the Oligocene, somewhere between 34 and 25 mya. Apparently, this species achieved its current, essentially land-locked distribution peculiar among sea-eagles due to the collision of Indian Plate with Eurasia
.
Thus, although the exact timing is not well resolved, it is quite certain that Pallas's Sea-eagles are the descendants of those sea-eagles which inhabited the northwestern Bay of Bengal
when it was a shallow straits separating mainland Asia from India, which still was an island at that time.
of Pallas's Fish Eagle is Vulnerable, with a population of about 2,500 to 10,000 remaining. Besides direct persecution, humans contribute to the decline of this species through habitat degradation, pollution
, and draining or overfishing lake
s. In India
, the eagle is also threatened by the spread of water hyacinth (Eichhornia spp.) which spread over lakes and make finding prey difficult. The large range
is deceptive, as Pallas's Fish Eagle is rare and isolated throughout its territory and may not breed in large areas of it.
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Cited texts
Sea Eagle
Sea eagle mainly refers to Sea eagle, birds of prey of the genus Haliaeetus.It may also refer to:-Aerospace:* Sea Eagle , British, anti-ship missile* Sea Eagle * Supermarine Sea Eagle, 1920s British passenger flying boat-Sports:...
. It breeds in Central Asia
Central Asia
Central Asia is a core region of the Asian continent from the Caspian Sea in the west, China in the east, Afghanistan in the south, and Russia in the north...
, between the Caspian Sea
Caspian Sea
The Caspian Sea is the largest enclosed body of water on Earth by area, variously classed as the world's largest lake or a full-fledged sea. The sea has a surface area of and a volume of...
and the Yellow Sea
Yellow Sea
The Yellow Sea is the name given to the northern part of the East China Sea, which is a marginal sea of the Pacific Ocean. It is located between mainland China and the Korean Peninsula. Its name comes from the sand particles from Gobi Desert sand storms that turn the surface of the water golden...
, from Kazakhstan
Kazakhstan
Kazakhstan , officially the Republic of Kazakhstan, is a transcontinental country in Central Asia and Eastern Europe. Ranked as the ninth largest country in the world, it is also the world's largest landlocked country; its territory of is greater than Western Europe...
and Mongolia
Mongolia
Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...
to the Himalayas
Himalayas
The Himalaya Range or Himalaya Mountains Sanskrit: Devanagari: हिमालय, literally "abode of snow"), usually called the Himalayas or Himalaya for short, is a mountain range in Asia, separating the Indian subcontinent from the Tibetan Plateau...
, Bangladesh
Bangladesh
Bangladesh , officially the People's Republic of Bangladesh is a sovereign state located in South Asia. It is bordered by India on all sides except for a small border with Burma to the far southeast and by the Bay of Bengal to the south...
and northern India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
. It is partially migratory
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
, with central Asian birds wintering among the southern Asian birds in northern India, and also further west to the Persian Gulf
Persian Gulf
The Persian Gulf, in Southwest Asia, is an extension of the Indian Ocean located between Iran and the Arabian Peninsula.The Persian Gulf was the focus of the 1980–1988 Iran-Iraq War, in which each side attacked the other's oil tankers...
.
Description
It has a light brown hood over a white face. The wings are dark brown and the back rufous, darker underneath. The tail is black with a wide, distinctive white stripe. Underwings have a white band. Juveniles are overall darker with no band on the tail. It measures 72 – in length with a wingspanWingspan
The wingspan of an airplane or a bird, is the distance from one wingtip to the other wingtip. For example, the Boeing 777 has a wingspan of about ; and a Wandering Albatross caught in 1965 had a wingspan of , the official record for a living bird.The term wingspan, more technically extent, is...
of 180–215 cm (70.9–84.6 in). Females, at 2.1-3.7 kg (4.6-8.2 lbs), are slightly larger than males, at 2-3.3 kg (4.4-7.3 lbs).
Its diet consists primarily of large freshwater fish.
Systematics
This species is the hardest-to-place sea-eagle. Among the speciesSpecies
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of its genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
, it has no close living relatives. mtDNA cytochrome b
Cytochrome b
Cytochrome b/b6 is the main subunit of transmembrane cytochrome bc1 and b6f complexes. In addition, it commonly refers to a region of mtDNA used for population genetics and phylogenetics.- Function :...
sequence
DNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
data is unable to reliably suggest a phylogenetic place for it among the sea-eagles. However, some information can be drawn from the molecular data, and especially from morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
and biogeography
Biogeography
Biogeography is the study of the distribution of species , organisms, and ecosystems in space and through geological time. Organisms and biological communities vary in a highly regular fashion along geographic gradients of latitude, elevation, isolation and habitat area...
:
This species retains the ancestral dark eye, bill
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
, and talon
Talon
A talon is a sharp claw of an animal, especially a bird of prey, such as the eagle, hawk, falcon, owl, or buzzard. It may also refer to:Places:* Talon, Nièvre, a commune in the Nièvre département in France...
s of the first sea-eagles, shared with the older tropical
Tropics
The tropics is a region of the Earth surrounding the Equator. It is limited in latitude by the Tropic of Cancer in the northern hemisphere at approximately N and the Tropic of Capricorn in the southern hemisphere at S; these latitudes correspond to the axial tilt of the Earth...
lineage. It is peculiar insofar as it has a black band at the end of the tail in adult birds, similar to juvenile Madagascar Fish Eagle
Madagascar Fish Eagle
The Madagascar Fish Eagle or Madagascar Sea-eagle is a large bird of prey in the family Accipitridae which also includes many other diurnal raptors such as kites, buzzards and harriers. The range of this eagle is within the Madagascar dry deciduous forests...
s (which look like a smaller, darker version of this bird, but are not very closely related). Its distribution indicates that this species evolved fairly independently of other sea-eagle lineages, but the molecular data tentatively suggests it is possibly closer to the Holarctic
Holarctic
The Holarctic ecozone refers to the habitats found throughout the northern continents of the world as a whole. This region is divided into the Palearctic, consisting of Northern Africa and all of Eurasia, with the exception of Southeast Asia and the Indian subcontinent, and the Nearctic,...
species.
It diverged from its common ancestor with other species soon after the Holarctic and the tropical lineages split. Dependent on the interpretation of a possible Early Oligocene
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
sea-eagle fossil from Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...
, this happened either at the very start or the end of the Oligocene, somewhere between 34 and 25 mya. Apparently, this species achieved its current, essentially land-locked distribution peculiar among sea-eagles due to the collision of Indian Plate with Eurasia
Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...
.
Thus, although the exact timing is not well resolved, it is quite certain that Pallas's Sea-eagles are the descendants of those sea-eagles which inhabited the northwestern Bay of Bengal
Bay of Bengal
The Bay of Bengal , the largest bay in the world, forms the northeastern part of the Indian Ocean. It resembles a triangle in shape, and is bordered mostly by the Eastern Coast of India, southern coast of Bangladesh and Sri Lanka to the west and Burma and the Andaman and Nicobar Islands to the...
when it was a shallow straits separating mainland Asia from India, which still was an island at that time.
Conservation status
The conservation statusConservation status
The conservation status of a group of organisms indicates whether the group is still extant and how likely the group is to become extinct in the near future...
of Pallas's Fish Eagle is Vulnerable, with a population of about 2,500 to 10,000 remaining. Besides direct persecution, humans contribute to the decline of this species through habitat degradation, pollution
Pollution
Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...
, and draining or overfishing lake
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...
s. In India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
, the eagle is also threatened by the spread of water hyacinth (Eichhornia spp.) which spread over lakes and make finding prey difficult. The large range
Range (biology)
In biology, the range or distribution of a species is the geographical area within which that species can be found. Within that range, dispersion is variation in local density.The term is often qualified:...
is deceptive, as Pallas's Fish Eagle is rare and isolated throughout its territory and may not breed in large areas of it.
Footnotes
References}}
Cited texts
External links
- ARKive: Images and movies
- BirdLife Species Factsheet
- H. leucoryphus range map (very large and slow to load)