Justification of Red List category
This species is classified as Vulnerable on the basis of a small estimated population which is suspected to be declining. It is judged to have distinct subpopulations, some totalling more than 250 birds. If subpopulations are found to be smaller or, conversely, that movement of birds between them means that all birds are in a single population, the species would warrant uplisting to Endangered.
The population is estimated to number 250-999 mature individuals based on an assessment of known records, descriptions of abundance and range size. This is consistent with recorded population density estimates for congeners or close relatives with a similar body size, and the fact that only a proportion of the estimated Extent of Occurrence is likely to be occupied. This estimate is equivalent to 375-1,499 individuals in total, rounded here to 350-1,500 individuals.
A moderate and on-going population decline is suspected on the basis of rates of habitat destruction and persecution.
Haliaeetus sanfordi is endemic to Bougainville and Buka, Papua New Guinea, and the Solomon Islands, where it occurs on most islands, excluding Rennell, including many tiny islets and reefs (Blaber 1990, Webb 1992, Buckingham et al. 1995, Cain and Galbraith 1956, Olsen 1997, G. Dutson pers. obs. 1997-1998, Dutson 2011). Highest numbers appear to be in the New Georgia group where a minimum territory size of 10 km2 was estimated in relatively undisturbed coastal habitat on Kolombangara (Buckingham et al. 1995), but four pairs were reported on the Three Sisters (12 km2) off Makira in the 1950s (French 1957). Birds are less common inland and on larger islands, e.g. Guadalcanal and Malaita (Cain and Galbraith 1956, Buckingham et al. 1995, G. Dutson pers. obs. 1997-1998), where numbers have declined within living memory (Buckingham et al. 1995, G. Dutson pers. obs. 1997-1998).
It prefers forested coasts (G. Dutson pers. obs. 1997-1998, Read 2013) where it scavenges and kleptoparasitises Osprey Pandion haliaetus (Blaber 1990, Webb 1992, G. Dutson pers. obs. 1997-1998). Some pairs also hunt far inland and others, especially on the eastern islands, appear to have entirely inland ranges where they prey largely on northern common cuscus Phalanger orientalis and perhaps arboreal rats and fruit bats (Buckingham et al. 1995, Olsen 1997, J. Hornbuckle in litt. 1999). It has been observed along primary rainforest lined rivers and over peaks in montane forest at elevations of 1,100 m, away from freshwater lakes (Pikacha et al. 2012). This species makes significant use of primary forests (Buckingham et al. 1990) but also hunts over open habitats such as deforested areas where it is reported to scavenge dead mammals including feral dogs (G. Dutson pers. obs. 1997-1998). Other observed prey include Glossy Swiftlets Collocalia esculenta, Solomons Flying-foxes Pteropus rayneri, Prehensile-tailed Skink Corucia zebrata (Pikacha et al. 2012), eel (Hadden 2004), possum (Phalangeridae) (Olsen 1997, Olsen et al. 2006), Pacific Black Ducks Anas superciliosa, domestic cats and chickens (Olsen 1997, Olsen et al. 2006). The few nests that have been recorded have been located in mangrove forest or rainforest (Olsen 1994,1997), and the only recorded active nest was found in an emergent tree in a near-coastal wetland within a mosaic of grassland and secondary forest (Petersson in press). Breeding ecology of this species is poorly understood but observations of both parents bringing food to a nestling (Petersson in press) suggests biparental care. The only record of an active nest reported a brood size of one, and a juvenile on the verge of fledging in mid-July suggests a hatching time of April and laying date of March (Petersson in press).
It is threatened by forest degradation from logging, which is ongoing and is often unsustainable, extracting too many trees to allow natural regeneration (e.g. Katovai et al. 2015). Over-fishing and silt run-off from logging and plantations are also likely to adversely affect it. Hunting for food and occasionally sport is a recent threat with a breakdown of traditional taboos, especially in the lowlands of larger islands (Cain and Galbraith 1956, Buckingham et al. 1995, G. Dutson pers. obs. 1997-1998). It is also killed in some villages to protect poultry, cats and dogs (Olsen 1997). It may suffer from competition with humans for the favoured prey-species P. orientalis. Capture of eagles for sale in the illegal pet trade to urban business people in Honiara (presumably as status symbols), is also considered a threat (Pikacha et al. 2012). In addition, the Solomon Islands is a region of high malaria infestation. Control of this mosquito-borne disease with chemicals such as DDT may affect H. sanfordi (Olsen 1994, 1995, 1997). Global Health Group & National Vector Borne Disease Control Program (2013) said that DDT has now been phased out in the Solomon Islands and the government has replaced with pyrethroid insecticides. DDT and other chemicals used in the Solomon Islands needs to be monitored (Olsen in litt. 2016).
Conservation Actions Underway
CITES Appendix II. It is well-known to Solomon Islanders and is often featured in environmental articles and postage stamps. It has legal protection in some provinces. Recent initiatives are promoting its protection in inland community projects (van Oosten and Wyant 1999).
70-90 cm. Only large eagle in the Solomons. Plain or mottled brown plumage. In flight, the very short tail and rather pointed wings swept upwards in a deep V are distinctive. Similar spp. Immature Brahminy Kite Haliastur indus has similar plumage but is smaller and has different flight action. Pied adult White-bellied Sea-eagle H. leucogaster are obvious but immatures differ only in having darker breast than belly, and brown tail (blacker in H. sanfordi) soon developing white base. Voice Series of honking cackles. Hints Common around forested islets in the Roviana and Morovo lagoons.
Text account compilers
Derhé, M., Dutson, G., Mahood, S., O'Brien, A., Stattersfield, A., North, A.
Dutson, G., Olsen, J., Hornbuckle, J., Debus, S.
BirdLife International (2023) Species factsheet: Haliaeetus sanfordi. Downloaded from http://datazone.birdlife.org/species/factsheet/sanfords-sea-eagle-haliaeetus-sanfordi on 29/11/2023.
Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://datazone.birdlife.org on 29/11/2023.