Document ID: chunk:federal_register_of_legislation:F2007B00391:body:0:p3
Version: federal_register_of_legislation:F2007B00391
Segment Type: other
Provision Reference: 
Character Range: 5564–8478

by playback of calls, Hill & Lill (1998a) found that owls were uniformly distributed throughout the two Primary and Marginal of rainforest at a density of 5.5  1.0 territories per square kilometre. They speculated that densities might be lower in some Marginal rainforests because of the more seasonal microclimates in areas exposed to the prevailing southeast winds. In regrowth vegetation they found that owls were present at significantly lower densities (1.7  1.1 territories/km2).

Approximately 75% of Christmas Island is still covered with natural vegetation and 84% of this (63% of the island) is within National Park (Figure 1). "Primary Rainforests" (du Puy 1993) outside the park are currently protected from clearance by a Federal Government moratorium, and Primary rainforest, Marginal rainforest and second-growth rainforest or regrowth vegetation may be removed only within the constraints of the EPBC Act and EPBC Regulations.

Rainforest rehabilitation has been occurring on Christmas Island for several decades. Currently, the main aim is to revegetate mined areas adjacent to Abbott's Booby nesting habitat in an attempt to reduce wind turbulence caused by the clearings and implicated in reduced nesting success of the booby (Reville et al. 1990). There are approximately 70 clearings covering 3200ha or 24% of the island area (Carew-Reid 1987). It is not known how long it will take for rehabilitation plantings to develop into forest which can be used by Christmas Island Hawk-Owls: it would not be long before these areas might be used for foraging, however, it is likely to be centuries before mature trees with nesting holes are available.

Ranging Habits
The ranging habits of adults in Primary rainforest have been studied by radio-tracking and territory mapping (Hill & Lill 1998a). Male and female pairs ranged within an apparently exclusive territory and two females radio-tracked used a smaller area than the two males tracked. One female of a pair occupied a smaller area that was wholly contained within that used by the male. Both females were preparing breeding at the time of being tracked and presumably range further when not breeding. Pairs defend their territory year round. Territorial boundaries appeared to be sharply delineated and crossings into neighbouring territories appeared to be rare. Territories appeared to be contiguous and were estimated to be 18ha in size on average. There is evidence that territories are contiguous in areas of Marginal rainforest (Hill & Lill 1998a). There are no data on the ranging habits of independent young.

Diet
Christmas Island Hawk-Owls are primarily insectivorous eating a wide variety of medium to large insects, especially Orthoptera, Lepidoptera, and Coleoptera. They also are recorded eating a range of vertebrates including Black Rats Rattus rattus, geckos, and Christmas Island White-eyes Zosterops natalis (Hill &