Crested Serpent Eagle

Serpent eagle ( Spilornis cheela )

The serpent eagle ( Spilornis cheela ) is a bird of prey from the subfamily of short-toed eagle ( Circaetinae ). It is distributed over large parts of indomalaiischen region and ranks up there with the relatively frequent raptor species.

Especially in the Malay Archipelago, the geographic variation is very pronounced. Of the many island forms many are considered by some authors as a separate species.

Description

The serpent eagle varies with 43-74 cm body length and a wingspan of 95-169 cm is very geographically in size. The nominate is greatest, reaching slightly more than the size of a serpent eagle, the smallest form, however, is about as big as a buzzard. The weight is about 420-1800 g, but is not well documented. Males and females differ little. However, females are about 4-6 % larger and probably significantly heavier than males.

In flight, the medium to large bird of prey affects großköpfig with a relatively long tail, which is usually kept closed, and rounded wingtips. She flies with strong wing beats and short gliding phases in which the wings level with the body axis or slightly above are maintained. In the glider they are held straight in a shallow V.

In adult birds, vertices, and neck plumage black. The latter is extended to a stand-up hood and variably lined beige or weißfleckig. The iris is yellow as well reins and cere. The rest of the top is dark brown, of which a fine white drawing of broken Endsäumen on shoulders, coverts and rump takes off. Chin, throat and sides of the head vary between black, greyish or brown. The light brown breast can -tight dark banded, finely scribbled or virtually unmarked. Abdomen, and under tail Beinbefiederung are more reddish brown with fine dark banding or a black -fringed, white mottling which varies greatly in size, shape and conspicuousness. The feet and legs are colored dull yellow. Especially in flight falls under hand, a broad white wing band on the otherwise blackish wings, which is formed by the whitish bases of the secondaries and a center band on the primaries; two narrower white bands often extend to the bases of the primaries. About the middle of blackish feathers runs an off-white band, which corresponds to the width of the wing band. Both features make the flight very striking image.

In juvenile plumage crown, sides of head and hood are yellowish beige to whitish with a black scale pattern. The black ear-coverts form a conspicuous, dark field. In addition, the bird is dark brown to blackish or reddish brown on the upper side with very variable whitish mottling, striping or lacing. The dark brown tail feathers show a whitish terminal band and two more, wide bright napkins. Upper hand, they are mottled brownish, grayish undersides. The beige white underside is sparsely marked with dark brown drops or dotting. Lower flanks, and under tail Beinbefiederung are often banded rusty brown.

Voice

The species is clamoring to hear especially in the expression flights before and during the breeding season, but otherwise quite ruffreudig. The typical call ( Sample ), a pervasive pi -pi- wieeh - wieeh, is one of the most commonly -heard, striking and catchy sounds of the birds of prey Orientalis. The initial two to three sounds are slightly quieter than the well audible one-, two - or three-syllable rarely cry that follows it.

Dissemination

The range of the serpent eagle extends over the majority of the Oriental and projects in the northeast and northwest a little in the Palaearctic into it. In the Malay Archipelago, the definition of the distribution area is heavily dependent on which island forms are counted as a subspecies of this type, or which species status is granted.

From single occurrences in Khyber Pakhtunkhwa and Sindh in Pakistan, the area extends eastward across the Indian subcontinent including Sri Lanka. In the northwest of the Himalayas limited to the deposit. The northern boundary runs here through Kashmir, Nepal, Bhutan and Assam, in China through Yunnan, Guizhou, Hunan and along the lower reaches of the Yangtze River. In East Asia, the spread of Hainan, Taiwan and the Ryukyu islands includes. To the south extends the area of the Andaman Islands, Nicobar Islands and Indo-China. From the Great Sunda Islands of Sumatra (including the Batu Islands, Mentawai Islands, Simeulue, Nias and Bangka ), Java colonized by Madura and Borneo. In the Philippines, the species is found only on Palawan, Balabac and the Calamian Islands. Furthermore, the Anambas Islands, the Natuna Islands, Bawean, Belitung and Bali belong to the breeding distribution.

Hiking

The serpent eagle is a sedentary bird in general. Were found only locally, seasonal migration or emigration from greater heights. Immature birds tend to dispersions

Geographical variation

The variation and systematics in the genus Spilornis with its many island forms is very complex and highly controversial. Altogether there are twenty-seven taxa. While many authors recognize only three or five of the island populations as a separate species, there are other up to thirteen. The International Ornithological Committee expects twenty subspecies to this style as a form of the Andaman Islands ( Elgini ), two of the Nicobar Islands ( minimus and ThomasHL ), one from North Borneo ( kinabaluensis ), the populations of the Philippines ( holospilus ) and Celebes ( rufipectus and sulaensis ) are each seen as a separate species.

The populations vary greatly partly in size so that the smallest forms three-fifths of small and partly by more than half are lighter than the greatest. A further feature is the varying coloration on the back of adult birds, ranging in the various forms of black-brown to pale brown to reddish brown to. Its the bottom ranges from blackish brown or chestnut brown to yellowish beige. The drawing of the underside is often very variable, ranging from a strong mottling or banding to a barely visible drawing.

• Sp ch. cheela ( Latham, 1790) - North India and Nepal
• Sp ch. melanotis ( Jerdon, 1844) - India south of Gujarat and the Gangetic plain
• Sp ch. spilogaster ( Blyth, 1852) - Sri Lanka
• Sp ch. burmanicus Swann, 1920 - Myanmar, southwestern China, Thailand and Indo-Chinese peninsula
• Sp ch. davisoni Hume, 1873 - Andaman and Nicobar Islands may
• Sp ch. ricketti Sclater, WL 1919 - northern Vietnam and southern middle and southeastern China
• Sp ch. perplexus Swann 1922 - Southern Ryukyu Islands
• Sp ch. hoya Swinhoe, 1866 - Taiwan
• Sp ch. rutherfordi Swinhoe, 1870 - Hainan
• Sp ch. palawanensis Sclater, W. L., 1919 - Palawan
• Sp ch. pallidus Walden, 1872 - lowlands in northern Borneo
• Sp ch. rich mondi Swann 1922 - Southern Borneo
• Sp ch. natunensis Chasen, 1935 - Natuna Islands and Belitung
• Sp ch. malayensis Swann, 1920 - Malay Peninsula from southern Tenasserim south and Anambas Islands and northern Sumatra
• Sp ch. batu Meyer de Schauensee & Ripley, 1940 - Southern Sumatra and Batu Islands
• Sp ch. abbotti Richmond, 1903 - Simeulue
• Sp ch. asturinus Meyer, A. B., 1884 - Nias
• Sp ch. bido ( Horsfield, 1821) - Java and Bali
• Sp ch. baweanus Oberholser, 1917 - Bawean

Habitat

The serpent eagle is found in a wide range of forest types, which includes both deciduous and evergreen forests, wet and dry, closed or semi-open habitats, as well as plains and mountain forests. It occurs in both primary and secondary forests or forests and plantations. Also interspersed with trees and shrubs savannah, wooded ravines or gallery forests is the way to find. At least on the Andamans it is also found in mangrove. The species also hunts in Proximity and in cultivated land. The altitudinal distribution extends to some 3,000 m.

Nutrition

The food of the serpent eagle consists mainly of reptiles, with snakes make up the majority and now drops to a lower percentage lizards. Occasionally added frogs and small mammals, rarely sick or injured birds. In the Andamans as crabs and eels have been found as loot.

The prey is usually captured by a residence dating, which is often located at the edge of a clearing and on the bird's sometimes a long time motionless sitting before he pushes down to an attack. Perhaps the lurking serpent eagle on tree-dwelling snakes or lizards also within the canopy. Flight hunting does not occur in this species.

Reproduction

The breeding season of the serpent eagle varies depending on geographical location and altitude above sea level. In the north of the range of the time of oviposition falls in the dry season. In the hill country of northern India it is from March to July, in the lowlands from February to May In southern India, it begins as early as December, in Myanmar there first nest from February. In Java you can find clutches in most months of the year, but usually from February to November.

The 50-60 cm in diameter and 10-30 cm in height relatively small nest is made of twigs and lined with green leaves. It is usually in the 6-20 m or more in a central fork. Nests are often found near water and can in forests, as well as in smaller trees in the semi-open landscape located. The nest consists of one, maybe sometimes even from two eggs and will incubate for approximately 35 days long. The boys fly off after about 60 days.

Fütternder adult birds at the nest

Mature nestling with attached hood imputed