Document ID: chunk:federal_register_of_legislation:F2006L03945:body:0:p3
Version: federal_register_of_legislation:F2006L03945
Segment Type: other
Provision Reference: 
Character Range: 5502–8352

population is crucial to the taxon's survival. Formerly a population believed to be much larger (but never estimated), occurred over the much greater area of the Southern Atoll of the CKI. The former distribution (extent of occurrence) on the Southern Atoll measured approximately 1400ha, so the geographic range has been reduced to less than 10% of its historical extent. The population on North Keeling Island is believed to be stable, and there is no evidence for historical or recent decline (Marchant & Higgins 1993; Taylor & Perlo 1998; Reid 2000).

Eight transect counts conducted on North Keeling Island by two observers in May 2005 yielded a density estimate of 7.00 birds ha-1 (s.e. 0.89). If the first count by a novice observer is removed, a density of 7.77 birds ha-1 (s.e. 0.45) is obtained. These densities translate to a population estimate of approximately 850 -1000 birds on North Keeling Island (Reid & Hill 2005).
Distribution
Located in the Indian Ocean (lat. 12° 12'S, long. 96° 54'E), the CKI are approximately 2900km north-west of Perth, 975km west-south-west of Christmas Island and 1,000km south-west of Java Head. They are an Australian Offshore Territory, comprising 27 separate islands (Fig. 1), 26 in the Southern Atoll, and North Keeling Island, located 24km to the north (lat. 11° 50'S, long. 96° 49'E). North Keeling Island, also Pulu Keeling National Park, is an internationally renowned seabird rookery and is listed as a wetland of international importance under the Ramsar Convention. A true coral atoll, North Keeling Island is low and flat with a large interior lagoon recently disconnected from the sea. Six main vegetated habitats can be recognised (after Gibson-Hill 1948; Williams 1994): tall Pisonia (Pisonia grandis) forest; tall Coconut (Cocos nucifera) open palm forest; lagoon fringing low forest of Ironwood (Cordia subcordata); patches of lagoon fringing shrub-thickets of Teabush (Pemphis acidula); a coastal, thin coralline strandline of low herbs; and patches of lagoon fringing herbland comprising grasses, sedges and Sea Purslane (Sesuvium portulacastrum), with admixtures of Pisonia-Coconut Palm and Pisonia-Ironwood forests. Octopus bush (Argusia argenta) is a common small tree of the sea coast at the edge of Pisonia-Coconut Palm stands, and Cabbage Bush (Scaevola taccada) is a patchily common shrub on forest margins. The CBBR utilises all habitats equally and occurs throughout North Keeling Island (Reid 2000), even foraging occasionally in the intertidal zone and to venture into shallow rock pools to bathe (Reid & Hill 2005). Up to 40 birds at one time have been seen foraging on the lagoon shore, and this seems to be a preferred feeding habitat (Hopton 2003; Reid & Hill 2005).

Habitat critical to survival
North Keeling Island is the habitat critical to survival of the CBBR. This