VOL. 17 (2) JUNE 1997 81

AUSTRALIAN BIRD WATCHER 1997, 17, 81-86

Notes on Sanford's Sea-Eagle Haliaeetus sanfordi and Other Raptors in the Solomon Islands by JERRY OLSEN, Applied Ecology Research Group, Faculty of Education, University of Canberra, P.O. Box 1, Belconnen, A.C.T. 2616

There are few published reports on raptors in the Solomon Islands (Brown & Amadon 1968; Schodde 1977; Hadden 1981; Cade 1982; Coates 1985; Fentzloff1989, 1990; Blaber 1990; Webb 1992, 1997; Gibbs 1996). In September 1990 I visited the Solomon Islands mainly as a tourist but also to look for Sanford's Sea-Eagle. Fourteen raptor species breed there and I report here on the eight raptor species I saw, and in some cases photographed, on the islands of Guadalcanal, in Guadalcanal Province, and Ghizo, Kolombangara and Kohinggo in the Western Province. The Solomon Islands are a scattered double chain of 992 islands, atolls and cays just south of the Equator, extending 1646 km in a south-easterly direction from Bougainville Island in Papua New Guinea. The six major islands, Guadalcanal, New Georgia, Malaita, Santa Isabel, Choiseul and Makira, vary in length from 87 to 171 km and in width from 25 to 50 km. The country's highest peak Makarakombu (2447 m) is on Guadalcanal and the islands are covered in dense rainforest, with mangroves, swamps and coconut plantations on the coasts. Rainfall averages 3500 mm but is closer to 6 m a year in many areas. Eleven diurnal and three nocturnal raptors breed in the Solomon Islands (Appendix 1 gives scientific names). Of these, Sanford's Sea-Eagle, Imitator Sparrowhawk and Fearful Owl are threatened (Collar et al. 1994).

Systematic list

Osprey Pairs of Ospreys nested in high densities on the coasts of Ghizo and Kolombangara. They were less common on the north coast of Guadalcanal where, when travelling by road, I saw only one nest between Honiara and Cape Esperance. This may be because the north Guadalcanal coast is heavily populated and covered with many coconut plantations. In addition, Guadalcanal has one of the highest, perhaps the highest, rate of malarial infection in the world and I saw DDT used there to spray huts. The spray canisters were rinsed in creeks and rivers that flowed onto the north coast. Raptors that eat other birds or large fish tend to be more affected by pesticides than those species that feed on mammals or insects (Newton 1979). Ospreys prey on large fish and may be affected by pesticides. The one nest located on 28 September near Cape Esperance, on the north-western comer of Guadalcanal, had parents feeding one flying young. On Ghizo and Kolombangara, where there were many nest trees, nests were 1.5 to 2 km apart. Ospreys were seen on three occasions fighting with other Ospreys, and once on a mountainside 1 km inland, with a raptor that could have been a Meyer's Goshawk. I saw no nests farther than 200m inland. Nests were often high on exposed limbs in dead trees. Ospreys were not persecuted and they nested in villages. One nest near Vanga Point on Kolombangara was at the top of a high tree, which the villagers called 'Pepeo', in a farmer's garden. The landowner said the pair fledged its single young in August that year. Teu Zhingihite, a village leader on Kolombangara (who also guided Jared Diamond during his research there), has observed birds in the area for 50 years. He said that Ospreys, and other raptors there, laid one egg and fledged one young each year. This was the case for Ospreys and the three other raptor species (Varied Goshawk, Bam Owl and Brahminy Kite) which I saw with young on Kolombangara. Webb (1997 and pers. comm.) has seen broods of two and three Varied Goshawks on Santa Isabel, but found clutches and broods of one more common. Brown Goshawks on Rennell may have broods of two young (Buckingham eta!. undated). AUSTRALIAN 82 J. OLSEN BIRD WATCHER

Pacific Baza These were fairly common in coconut plantations and villages. One pair hunted in the town of Ringgi on Kolombangara on 25 to 28 September but I found no nest. They were large, slow-flying hawks with heavily barred underparts, apparently of the subspecies Aviceda subcristata gurneyi. They had flight action similar to a pigeon, were tame, and appeared to forage in the tree canopy.

Brahminy Kite These kites nested cornnfonly along the shoreline in the same coastal habitat as Ospreys. On Kolombangara nests were about 1.5 to 2 krn apart as with the Osprey. I saw no conflict between Ospreys and Kites even at one site where the Ospreys and Kites nested about 40 m apart in a village. As with Ospreys, villagers did not molest them. Nests were in live trees and were lower and more surrounded by foliage than were nests of Ospreys. One on Kolombangara was 20 m up in the fork of a tree that natives called 'Magroo'; on 20 September the female was brooding a single downy young less than a week old. As reported by Bell (1985), these kites commonly foraged under the canopy in rainforest high on mountainsides 1.5 krn inland. They behaved like forest buteos, e.g. Red-shouldered Hawks Buteo lineatus. I saw no Kites nesting in the forest.

Sanford's Sea-Eagle This eagle is the largest avian predator in the islands and, unlike Brahrniny Kites and Ospreys, it was killed by locals because it was.said to catch dogs, cats, poultry and other animals valued by these villagers. Australian Catholic priests at Vanga Point apparently shot the local eagles as part of their teachings about raising poultry and other stock. In pre-Christian times Sanford's Sea-Eagle was worshipped as a totem and, therefore, not killed. This changed as values and beliefs changed. Locals also told me that the Sea-Eagles catch many possums, and do this sometimes by landing on the trunk of a tree and grabbing the possum as it comes out. Some villagers thought that eagles frightened possums out by scratching the trunk, whereas others said that possums carne out because eagles spread their wings over the hollow so possums thought it was night (they apparently are nocturnal whereas the eagle is diurnal). The former explanation seems more likely than the latter. Villagers also said that eagles robbed Brahrniny Kites and Ospreys of fish, so these smaller species fought with and drove away eagles corning down from the mountains to the shoreline. I saw no Sea-Eagles on the shoreline of any island, though I spent three full days searching from motorised canoe. Some raptors that locals pointed to and called Sea-Eagles were juvenile Brahrniny Kites fishing or soaring on hillsides. The Kites were about the same colour as Sea-Eagles and looked large in certain environments. On 22 September at 1600 h I saw a Sea-Eagle soaring high up on the flanks of Mt Mbatuvana on Kolombangara. The eagle was very like a juvenile White-bellied Sea-Eagle Haliaeetus leucogaster or a large, heavy juvenile Brahrniny Kite. It soared with the characteristic V -shaped dihedral of the White-bellied Sea-Eagle, giving the impression of a very heavy-bodied bird, and had a very short tail and shorter wings than White-bellied Sea-Eagles with which I am familiar near Canberra. On 24 September I travelled in a truck from the local forestry operation to a point 350 m up Mt Rano on Kolombangara. I travelled to a small deforested patch there on the assumption that it may be easier to find the eagle in remnant, as opposed to continuous, tracts of rainforest. At 1000 h a Sanford's Sea-Eagle flushed from a dead possum along the side of the road in front of us and flew to a tree where I photographed it (Plate 7). Again, the eagle looked like a juvenile White-bellied Sea-Eagle though the colouring was different. The bird did not look like that in Plate 29 of Brown & Amadon (1968), the only pictorial representation I could find of the eagle. Its tail was much shorter than that shown in Brown & Amadon, and its body shape, when perched, was similar to that of the Palm-nut Vulture Gypohierax angolensis (also pictured on Plate 29 of Brown & Amadon) as the wings extended well past its short tail. The bird perched upright like the vulture depicted and unlike the Sanford's Sea-Eagle depicted. The colour also was different. It was overall a slaty, sooty dark brown with a lighter tan-coloured face and throat and a bare patch behind its beak. The eagle had a full crop, apparently of possum, that protruded white through the brown and tan feathers of the upper breast. The beak was laterally flattened as in White-bellied Sea-Eagles, and the bird flew in a similar slow, heavy fashion but on shorter wings that appeared wide near the body, i.e. the secondaries were longer or appeared longer because the primaries of this individual were shorter than in the White­ bellied Sea-Eagles I had observed. It flew to a logged clearing farther up the road where it perched for the afternoon. It did not seem to have the agility of a forest eagle and showed some reluctance to leave the clearing when I flushed it. My impression was that it could hunt over clearings, roads, rivers and the shore but could not easily hunt in dense rainforest. Except for colouring, the bird was ve!"Y similar to a White-bellied Sea-Eagle. VOL. 17 (2) JUNE 1977 Raptors of the Solomon Islands 83

Sanford's Sea-Eagle on Kolombangara, Solomon Islands, 24 September 1990. Plate 7 Photos: Jerry Olsen

Recently fledged Varied Goshawk (still being fed by its parents) on Kolombangara, Solomon Islands, 20 September 1990. Plate 8 Photo: Jerry Olsen

I found no active nests of the species but was shown three disused nest sites by locals , on Kolombangara, Kohinggo and Guadalcanal. All three were similar to White-bellied Sea-Eagle nests in riparian settings in New South Wales. The first nest, on Kolombangara, was in a giant rainforest tree about 1 km from the sea up the Patupaele River. There were many Pacific Black Ducks Anas superciliosa on the river (they are teal-sized in the Solomon Islands), and my guide, Teu Zingihite, said they were used by the eagles for food. He has seen eagles eating these, possums and other prey on the ground, especially on sand-bars in the rivers. He also said that eagles added material to their nests each year until, eventually, the nest fell down. He and others told me that Brahminy Kites and Ospreys harass these eagles to such an extent that some move their nests inland after a nest falls. If this is so, the two smaller raptors may be increasing in number and gaining sole use of the shoreline for nesting. A second abandoned nest site, on Kohinggo Island, was in a large swamp 200 m inland from the sea. The nest had been 30 m up in a large tree but the branch had broken and the nest fallen. We saw one Sanford's Sea-Eagle soaring about 1 km inland near the centre of this island, so the pair may have moved after the nest fell. AUSTRALIAN 84 J. OLSEN BIRD WATCHER

A third abandoned nest was 4 km up Bonegi Creek near Honiara on Guadalcanal. A cyclone in the previous year had created refugee villagers from the south side of the island and some of these villagers had settled on Bonegi Creek opposite the nest, apparently causing the pair to abandon the site; in addition I was told that the locals had shot one of the eagles. In summary, the status of Sanford's Sea-Eagle was not clear from these limited observations but the eagles were persecuted and may be in danger of extinction if persecution and habitat destruction continue. Brown Goshawk Not seen. This goshawk occurs in the Solomons only on Rennell Island in the central south. Varied Goshawk This was the common accipiter on Guadalcanal and Kolombangara. Locals called it 'Buti'. It is a small sparrowhawk-sized accipiter but slower than a sparrowhawk or the Pied Goshawk which, though larger, is probably 'sparrowhawk'-like in foraging ecology. The Varied Goshawk flew much like a Shikra Accipiter badius and was about the same size. Locals on Kolombangara considered this raptor slow and lazy. On 20 September near Vanga Point on Kolombangara, locals showed me a nest of this species in a tree that villagers called ' Naka'. The tree, which locals said never grows very big, was outside a farmer's house and the nest was about 16 m up, two-thirds of the way up the tree. The nest was a flat structure about 35 em across in a fork in the bushy centre of the tree. At about 20-minute intervals over two hours, an adult returned with a small skink-like brown lizard to feed the fully grown single young on the nest. The adult had short round wings and a short square tail, and was clear slate-grey above and rich dark chestnut below as is the rufous race A. novaehollandiae rubianae. The young was similar to the grey morph of nominate novaehollandiae, found on the east coast of Australia, with grey back and head, white throat and underparts, and yellow cere and legs (Plate 8) . The farmer said the pair had caught several newly hatched chickens from his yard so, as I left, he threatened to cut down the nest tree. This is the only nest record I could find for this species on Kolombangara. Webb (1997) found nesting pairs on Santa Isabel- one pair was seen nest-building in June, laid two eggs in early July, and had large nestlings in late August; two other pairs had two nestlings each in July 1987, and another had three nestlings in August 1988. These goshawks were common throughout the forest on Kolombangara and, according to locals, even on the smallest offshore islets. I saw them soaring just above the forest canopy at 500 m elevation.

Pied Goshawk I saw one (pale morph) over the town of Gizo, on the island of Ghizo in the Western Province, at midday on 18 September. The bird, about the size of a male Brown Goshawk, carried a lizard over the town and an open field to a range of trees. It was not pursued or harassed by other birds. This goshawk was not as common as the Varied Goshawk, but I saw Pied Goshawks four times in forest on Kolombangara. Villagers said this species was larger, faster and more aggressive than the Varied Goshawk. The bird appeared to be more of a sparrowhawk than a goshawk, with long bird­ catching toes, like Cooper's Hawk Accipiter cooperi. Imitator Sparrowhawk Not seen. Said to be rare and threatened. Meyer's Goshawk I made no positive sightings of this large accipiter, though may have seen one soaring and fighting with Ospreys high up on Mt Veve on Kolombangara. If so, this hawk may have had limited time to hunt because this cloud forest was covered by mist every day from about 1000 h. In the forest on Kolombangara there were several species of medium-sized to large prey, 300 to 1000 g, that could suit a goshawk this size and, perhaps, the Peregrine Falcon. These included flying-foxes, fruit-pigeons, Buff-headed Coucals Centropus milo, and Solomon Corellas Cacatua ducorpsii. Oriental Hobby Not seen. One was positively identified by Buckingham et al. (undated) at the same location on Kolombangara'where I photographed the Sanford's Sea-Eagle.

Peregrine Falcon I saw one Peregrine Falcon on Bonegi Creek 4 km upstreamJrom the sea on the north coast of VOL. 17 (2) JUNE 1997 Raptors of the Solomon Islands 85

Guadalcanal. The falcon flew down along the creek through a high-sided gorge covered with vines and forest on steep hills. It appeared to be a medium-sized, short-winged subspecies but whether it was F.p. emesti or nesiotes I could not say. No cliffs were evident but there could have been some farther up the creek and there were several good cliffs on other rivers on Guadalcanal. My local guide said that his villagers called this falcon 'Roha Bora' (Black Hawk) and said it swooped down at great speed onto birds. I could find no other records in the literature for Peregrine Falcons on Guadalcanal, though they have been recorded on Three Sisters (French 1957) and Makira (Buckingham et a! . undated).

Barn Owl From 19 to 21 September, one pair was observed feeding a single nestling throughout the night in a village near Vanga Point on Kolombangara. The nest hollow was near the top of a rainforest tree in a small coconut plantation. The young gave a typical Barn Owl food-begging call from just after dusk to just before dawn and appeared to be fed about once per hour. This is the only nest record I could find for this species in the Solomon Islands.

Solomons Boobook Not seen. This owl is apparently quite common and similar to the Southern Boobook Ninox novaeseelandiae in habits.

Fearful Owl Not seen. This owl is said to live on arboreal rats and other forest mammals, as do large Ninox species (Burton 1973, Webb 1992). These food sources may be disappearing and the owl may be threatened.

Discussion Sanford's Sea-Eagle was not common in the areas I visited and seemed to nest away from villages and the coast, though, given the nature of these islands, the nests I saw were all within walking distance of the coast. Schodde (1977) said, 'Being a predator of larger land mammals and birds and foraging far inland, it seems to be much more of a land eagle than its allospecies, H. leucogaster. It nevertheless frequents the sea shore and feeds on fish from time to time' (p. 35). However, Fentzloff (1989) said this eagle was 'no forest or mountain sea eagle' because he claimed to have seen it foraging along the coast, and Webb (1992) saw one feeding on a shark on Fera Island off Santa Isabel. Blaber (1990) saw them around New Georgia taking fish discards from the water surface after the fashion of other fish-eagles, but he did not see them in true forest areas or eating mammals as I did. Buckingham et al. (undated) saw them regularly at low densities in the Western Province, but at only one site on Makira and not at all on Guadalcanal. The eagles made significant use of primary forests up to at least 1000 m for hunting and were rarely seen away from tall trees and old-growth forest. On Kolombangara, Buckingham et al. saw two birds carry prey from primary forest towards the coast and estimated their minimum home-range to be 10 km2 • Gibbs (1996) considered Sanford's Sea-Eagle to be still widespread, with sightings on Malaita, Makira, and Choiseul where it 'remains fairly common'. The foraging habits of Sanford's Sea-Eagle may be similar to those of the White­ bellied Sea-Eagle which also nests far inland (Marchant & Higgins 1993) and, near Canberra, hunts mammals and birds as well as fish (pers. obs.). The Sanford's Sea­ Eagles I observed appeared very similar to these White-bellied Sea-Eagles. Coates (1985) said that nesting habits were not described for Sanford's Sea-Eagle and I could find no description in the literature. Buckingham et al. (undated) had one possible but no definite nest sightings. The nests of Sanford's Sea-Eagle appear to be similar to those of the White-bellied Sea-Eagle, but persecution may stop Sanford's from nesting along the coast as sea-eagles do in Australia. Like the White­ bellied Sea-Eagle, Sanford's does nest in tall trees along rivers and swamps. AUSTRALIAN 86 J. OLSEN BIRD WATCHER

The status of Sanford's Sea-Eagle is unclear and its numbers may be declining with the destruction of primary forest. There are no detailed data on pesticide contamination, diet, breeding and non-breeding behaviour. Studies are needed on all diurnal and nocturnal birds of prey in the Solomon Islands as some, like the Fearful Owl, may already be lost or close to being lost.

Acknowledgements Particular thanks go to Susan Trost and Teu Zingihite for their help with these observations, and to Stephen Debus and Horace P. Webb for comments on the manuscript. References Bell, H. (1985), 'Distribution and habits of kites, Milvus migrans, Haliastur sphenurus and H. indus in Papua New Guinea', Corella 9, 37-48. Blaber, S.J.M. (1990), 'A checklist and notes on the current status of the birds of New Georgia, Western Province, Solomon Islands', Emu 90, 205-214. Brown, L., & Amadon, D. (1968), Eagles, Hawks and Falcons ofthe World, Country Life, London. Buckingham, D.L., Dutson, G.C.L. & Newman, J.L. (undated), Birds of Manus, Kolombangara and Makira (San Cristobal) with Notes on Mammals and Records from other Solomon Islands, unpublished report of the Cambridge Solomons Rainforest Project 1990. Burton, J.A. (Ed.) (1973), Owls of the World, Dutton, New York. Cade, T. (1982), The Falcons of the World, Collins, London. Coates, (1985), The Birds of Papua New Guinea, vol. 1, Dove, Brisbane. Collar, N.J., Crosby, N.J. & Stattersfield, A.J. (1994), Birds to Watch 2: The World List ofThreatened Birds, Birdlife Internatl, Cambridge (UK). Fentzloff, C. (1989), 'Sanford Expedition 1989', World Working Group on Birds ofPrey News/. 11, 5-9. --(1990), 'Sanford Expedition 1989', World Working Group on Birds of Prey News/. 12, 3-5. French, W. (1957), 'Birds of the Solomon Islands', Ibis 99, 126-127. Gibbs, D. (1996), 'Notes on Solomon Island birds', Bull. Brit. Omithol. Club 116, 18-25. Hadden, D. (1981), Birds ofthe North Solomons, Wau Ecology Institute, Wau (Papua New Guinea). Marchant, S., & Higgins, P.J. (Eds) (1993), Handbook of Australian, New Zealand and Antarctic Birds, Volume 2, Raptors to Lapwings, Oxford University Press, Melbourne. Newton, I. (1979), Population Ecology of Raptors, Buteo, Vermillion (South Dakota). Schodde, R. (1977), 'Contributions to Papuasian Ornithology. VI. Survey of the birds of southern Bougainville Island, Papua New Guinea', CSIRO Div. Wild/. Res. Tech. Paper 34. Webb, H.P. (1992), 'Field observations of the birds of Santa Isabel, Solomon Islands', Emu 92, 52-57. --(1997), 'Nesting and other observations of Solomon Island birds' , Aust. Bird Watcher 17, 34-41 . Received 12 April 1996

Appendix 1

Breeding raptors in the Solomon Islands.

Osprey Pandion haliaetus leucocephalus Pacific Baza Aviceda subcristata gumeyi Brahminy Kite Haliastur indus flavirostris Sanford's Sea-Eagle Haliaeetus sanfordi Meyer's Goshawk Accipiter meyerianus Brown Goshawk Accipiter fasciatus fasciatus Varied Goshawk Accipiter novaehollandiae (rubianae, rufoschistaceus, malaitae, pulchellus) Imitator Sparrowhawk Accipiter imitator Pied Goshawk Accipiter albogularis (woodfordi, gilvus, albogularis, sharpei) Oriental Hobby Falco severus papuanus Peregrine Falcon Falco peregrinus emesti? nesiotes?

Bam Owl Tyto alba (delicatula, interposita) Solomons Boobook Ninox jacquinoti Fearful Owl Nesasio solomonensis •