Grey-headed fish eagle (Ichthyophaga ichthyaetus)
|Also known as:||Grey-headed fish-eagle, grey-headed fishing eagle|
|Size||Length: 61 - 75 cm (2)|
Male wingspan: 42 - 45.5 cm (3)
Female wingspan: 44.5 - 51.8 cm (3)
Male weight: 1.6 kg (3)
Female weight: 2.3 - 3.7 kg (3)
Classified as Near Threatened (NT) on the IUCN Red List (1) and listed on Appendix II of CITES (4).
The grey-headed fish eagle is a striking bird and an impressive hunter, with a relatively small head, longish neck and a powerful, grey beak. The plumage is brownish-grey on the upperparts and white below (2) (3). It has relatively short legs, a rounded tail, sandy-yellow eyes, and long, black talons. The female grey-headed fish eagle is usually larger and heavier than the male (2) (3) (5), and juveniles can be recognised by the white belly mottled with brown (2) (3).
The grey-headed fish eagle is sometimes mistaken for the lesser fishing eagle (Ichthyophaga humilis); however, the grey-headed fish eagle can be distinguished by its darker, duskier plumage and its tail, of which the last two-thirds of the tail are white, compared to the lesser fishing eagle which has a darker tail with no obvious white banding (2) (3).
The calls of the grey-headed fish eagle include loud gurgles to the tune of awh-awhr and chee-warr repeated five to six times, and owlish oo-wooks. Somewhat disturbingly for other jungle inhabitants, the vocal range of this bird also includes a high-pitched scream (3).
The range of the grey-headed fish eagle extends from India, Nepal, Sri Lanka, east through Southeast Asia, to the Philippines and Sulawesi (2).
This bird is mostly found in lowland forests up to elevations of 1,525 metres, near large, slow-flowing bodies of water (such as lakes, reservoirs, and streams), as well as in estuaries and along the coast (2) (5) (6).
True to its name, the grey-headed fish eagle feeds primarily on fish, but it will also take other prey, including reptiles, depending on local availability. To hunt for its fish prey, this eagle will usually perch on bare branches overlooking a body of water, before executing a short flight to snatch its prey once observed near or at the surface. Should the fish eagle’s catch be too big and heavy to be flown off, it will drag its prey onto the bank (2) (3) (5) (7).
The breeding season of the grey-headed fish eagle generally takes place between November and May. During this period, the grey-headed fish eagle is known to be rather noisy, often calling out at night (2) (3).The nest, which is constructed from sticks and lined with green leaves, is usually reused for several years in succession, and can be up to 1.5 metres wide and 2 metres deep. The nest is situated high up in the trees, (between 10 and 30 metres), and always near water. Usually one or two, occasionally three, pure white eggs are laid per mating couple. Incubation of the eggs is undertaken by both the male and female (2) (3) (5), and is likely to last between 45 to 50 days (8).
Although not currently considered to be threatened with extinction, the population of grey-headed fish eagles is declining – the result of numerous and varied threats. The loss of suitable wetland habitat, over-fishing, and pollution result in a loss of nesting sites and reduced food supply. In addition, the construction of dams on the Mekong River is likely to affect the flood regime of the Tonle Sap lake, negatively affecting the grey-headed fish eagle population residing there (6) (7).
Although there are no active conservation measures currently in place for the grey-headed fish eagle, there is an annual monitoring programme for the breeding population in a protected area at the Tonle Sap lake in Cambodia, which has been conducted each year since 2006. The programme provides baseline information on the ecology of the species and the status and distribution of the breeding population (7). A number of conservation actions have also been recommended; these include protecting areas known to be important to the species and carrying out awareness campaigns to encourage local people to protect both the grey-headed fish eagle and its wetland habitat (6).
To learn about the conservation of birds of prey see:
The Peregrine Fund:
Eagle Conservation Alliance:
For more information on this and other bird species please see:
- BirdLife International:
Authenticated (06/09/10) by Dr Malcolm Nicoll, Centre for Agri-Environmental Research (CAER), Department of Agriculture, The University of Reading.
- Incubation: the act of incubating eggs, that is, keeping them warm so that development is possible.
IUCN Red List (May, 2010)
- del Hoyo, J., Elliott, A. and Sargatal, J. (1994) Handbook of the Birds of the World. Volume 2: New World Vultures to Guineafowl. Lynx Edicions, Barcelona.
- Ferguson-Lees, J. and Christie, D.A. (2001) Raptors of the World. Christopher Helm, London.
CITES (June, 2010)
- Smythies, B.E. (1981) The Birds of Borneo. The Sabah Society and the Malaysian Nature Society, Kota Kinabalu and Kuala Lumpur.
BirdLife International (May, 2010)
- Tingay, R.E, Nicoll, M.A.C. and Visal, S. (2006) Status and distribution of the grey-headed fish-eagle (Ichthyophaga ichthyaetus) in the Prek Toal core area of Tonle Sap Lake, Cambodia. Journal of Raptor Research, 40: 277-283.
- Nicoll, M.A.C. (2010) Pers. comm.