Document ID: chunk:federal_register_of_legislation:F2007B00386:body:0:p3
Version: federal_register_of_legislation:F2007B00386
Segment Type: other
Provision Reference: 
Character Range: 5523–8453

encountered diurnal forest bird and might best be described as 'widespread and uncommon'.

There are no data on adult or juvenile movements. Adult Christmas Island Goshawks are probably resident on their territories year-round. Grey Goshawks defend a territory around the nest site which appears to be significantly smaller than the home range in which they feed (Burton 1991).

There are no detailed population estimates for Christmas Island Goshawks. New Caledonian Brown Goshawks, a similar-sized closely related bird, occurred at a density of 0.89 - 0.96 adults/km2 in rainforest (Thiollay 1993). There is approximately 101 km2 of primary forest on Christmas Island which suggests that it is unlikely that there are many more than 50 pairs or 100 mature Christmas Island Goshawks on Christmas Island.

Biology
The Christmas Island Goshawk has been recorded eating a wide range of vertebrates and invertebrates including birds, small mammals and insects. Prey includes Christmas Island White-eye Zosterops natalis, Island Thrush Turdus poliocephalus, Emerald Dove Chalcophaps indica, Java Sparrow Lonchura oryzivora, domestic chickens Gallus gallus,  (Lister 1888, Gibson-Hill 1947, Hill, unpubl. data); as well as nestling Red-footed Boobies Sula sula (Hill, unpubl. data) and an adult Golden Bosun Phaethon rubricauda westralis (J. Tranter pers. comm.). It has also been recorded catching rats Rattus rattus (Gibson-Hill 1947) and 'lizards' (Lister 1888). It is frequently seen catching grasshoppers (probably Valanga sp.) which are common in secondary vegetation around the island (Gibson-Hill 1947, Hill unpubl. data). Gibson-Hill (1947) also recorded it feeding on the large centipede Scolopendra morsitans, which is widespread on the island, and on beetles (Coleoptera) and mantids (Mantidae).

The Christmas Island Goshawk captures its prey off the ground or in the air by seizing it in flight with its long, strong legs. Like other goshawks, it will hunt from a perch where it may sit for some time waiting for suitable prey. Christmas Island Goshawks will chase small flying birds through the forest as well as pounce on birds foraging on the ground (Hill unpubl. data). Hill observed goshawks 'short-stay perch-hunting' (after Newton 1986) flying along a track, perching for a few minutes then flying 50-100m further and landing again, as well as pursuing insects on the ground and snatching insects off foliage. There is likely to be some sex differences in hunting and in diet, as is found in both Brown and Grey Goshawks (Marchant & Higgins 1993). Given the large sexual dimorphism (similar to Grey Goshawk, Hill unpubl. data) and the opportunity for niche expansion on the island in the absence of other diurnal raptors, this difference may be quite pronounced.

Gibson-Hill (1947) described three Christmas Island Goshawk nests all of which were in near-horizontal forks of forest trees, one 10m high and two