Crested serpent-eagle
| Crested Serpent-eagle | |
|---|---|
| Scientific classification | |
| Kingdom Information | |
| Domain | Eukaryota |
| Kingdom | Animalia |
| Subkingdom | Bilateria |
| Branch | Deuterostomia |
| Phylum Information | |
| Phylum | Chordata |
| Sub-phylum | Vertebrata |
| Infraphylum | Gnathostomata |
| Class Information | |
| Superclass | Tetrapoda |
| Class | Aves |
| Sub-class | Neornithes |
| Infra-class | Neoaves |
| Order Information | |
| Order | Accipitriformes |
| Sub-order | Accipitres |
| Family Information | |
| Superfamily | Accipitroidea |
| Family | Accipitridae |
| Sub-family | Circaetinae |
| Genus Information | |
| Genus | Spilornis |
| Species Information | |
| Species | S. cheela |
| Population statistics | |
| Conservation status | Least concern[1] |
The crested serpent-eagle (Spilornis cheela) is a species of bird of prey of the family Accipitridae, and found within tropical forests across much of southeastern Asia.
Description
The crested serpent-eagle is medium-sized, with a body length of 16.8 to 29.2 inches, a wingspan of 37 to 66 inches, and weighs between 14.0 and 63.4 ounces. Females are about 4-6% larger and probably much heavier than males. The nominate form (S. c. cheela) is the largest of the subspecies.
Overall, the bird is dark brown to greyish brown in color, depending on the subspecies, with darker wings spotted in white at the bend. The top of the head is black, extending in a white-spotted crest in the back. Chest and belly are lighter in color, and lightly-spotted in white. In flight the wings - which are held in a shallow "V" when gliding - bear one or two white bands on the primaries and secondaries; this banding is repeated in the tail. Juvenile birds are dark brown above with extensive whitish-tipped feathers, and very light in color on the chest and belly.
Its calls are loud in flight before and during the breeding season. The typical call[2], a penetrating "pi-pi-wie-wie-wieeh", is one of the most commonly heard calls by any bird of prey in southeastern Asia.
Subspecies
The subspecies sometimes vary greatly in size, so that the smallest forms are three-fifths smaller and sometimes more than half the size of the largest. Another variable feature is the coloration of the upperparts of adult birds, ranging from blackish brown to reddish brown to pale brown in the various forms. The underside ranges from blackish brown to chestnut brown to a yellowish beige, with streaks or banding or a light wash of color which is barely visible.
- Spilornis cheela asturinas; Indonesia: Nias Island
- Spilornis cheela batu; Indonesia: southern Sumatra, Batu Islands
- Spilornis cheela bido; Indonesia: Java and Bali
- Spilornis cheela burmanicus; Myanmar to southwestern China, Thailand and Indochina
- Spilornis cheela cheela; northern India and Nepal
- Spilornis cheela davisoni; India: Andaman Islands
- Spilornis cheela hoya; Taiwan
- Spilornis cheela malayensis; Malay Peninsula, northern Sumatra and Anambas Islands
- Spilornis cheela melanotis; Indo-Gangetic plain
- Spilornis cheela palawanensis; Philippines: Palawan
- Spilornis cheela pallidus; Lowlands of northern Borneo
- Spilornis cheela richmondi; Indonesia: southern Borneo
- Spilornis cheela ricketti; southern China and northern Vietnam
- Spilornis cheela rutherfordi; China: Hainan
- Spilornis cheela spilogaster; Sri Lanka
The variation of both species and subspecies within the genus Spilornis - especially the numerous island forms - is very complex and highly controversial. Authorities have described a total of twenty-seven taxa. While many authors recognize only three or five of the island's populations as separate species, others count up to thirteen. The Global Raptor Information Network recognizes thirteen species[3], while the International Ornithological Union counts twenty-five species and subspecies under the crested serpent-eagle name alone[4]. Once considered subspecies under S. cheela, the following are recognized as species by many authorities:
- Andaman serpent-eagle, Spilornis elgini
- Great Nicobar serpent-eagle, Spilornis klossi
- Kinabalu serpent-eagle, Spilornis kinabaluensis
- Philippine serpent-eagle, Spilornis holospila
- Sulawesi serpent-eagle, Spilornis rufipectus
Range and habitat
The crested serpent-eagle has a large range over much of southern and southeastern Asia, from the Indus river valley in Pakistan eastward along the southern Himalaya mountains to China, and south to Sri Lanka, Indochina, and much of Indonesia. It is found in a wide range of forest types, including both primary and secondary forests and plantations, deciduous and evergreen forests, wet and dry, closed or semi-open, from sea level to more than 9,000 feet elevation. The species can also be found in savannah interspersed with woodland, wooded ravines or gallery forests; within the Andaman Islands it can also hunt and nest within mangrove. The species also hunts near human settlements and in cultivated land.
Diet
The prey is usually captured from a perch; the bird is predominantly a still hunter, and will usually sit motionless at the edge of a clearing before it makes an attack. Food consists mainly of reptiles, with snakes making up the largest part, with lizards, frogs and small mammals taken; rarely taken when the opportunity arrives are sick or injured birds. On the Andaman Islands crabs and eels are part of the diet.
