BirdsBirds

Birds

Table 4 lists the birds recorded for the Park and the whole of the Cocos (Keeling) Islands.

When Charles Darwin visited the Cocos (Keeling) Islands in April 1836, the ‘immense number’ of marine birds recorded in 1828-29 on the main atoll (cited in Gibson-Hill 1949) were probably somewhat diminished. Darwin however refers to trees on the southern atoll being occupied by many nests of gannets [sic], frigate birds and terns, and to a smell in the air which led him to call it a ‘sea rookery’ (Darwin 1979). From Darwin’s diary, it would appear that the forest of the southern atoll was by then well on the way to being transformed into the monoculture coconut plantation that it had become by 1885, when most birds had been eliminated from the southern atoll (Forbes 1885). The reason for this decline was almost certainly due to habitat change, intense hunting and predation by cats and rats. Today, there are still very few birds on the southern atoll.

Birds remain in large numbers on North Keeling Island due to its isolation, the difficulty of landing, the absence of any feral predators and access restrictions placed by the former Clunies-Ross family up to the mid 1970s (Stokes 1994).

Of the approximately sixty species of birds recorded from the Cocos (Keeling) Islands, twenty-five have been seen on North Keeling Island in the last twenty years. Of those twenty-four, fifteen breed on the island, possibly sixteen if the Round Island petrel, Pterodroma arminjoniana, is confirmed to breed there. All species recorded from North Keeling Island are protected by the EPBC Act, being listed threatened species (critically endangered, endangered or vulnerable), listed migratory species or listed marine species under the Act.

North Keeling Island is also one of the few remaining near-pristine tropical islands in the Indian Ocean (Stokes et al. 1984), and is the only seabird breeding colony within a radius of 975 kilometres. Unsurprisingly, therefore, the island is the focal bird habitat within a huge expanse of the central-eastern Indian Ocean. It is unlikely that any other Indian Ocean island rivals North Keeling’s range of seabird species (Feare 1984; Stokes and Goh 1987). However, the health of many of the island’s seabird species is largely unknown, with careful management is required to avoid the decline in seabird populations seen on other Indian Ocean islands over the last 100 years.

By far the most numerous seabird on North Keeling Island is the red-footed booby Sula sula. Based on comprehensive population surveys between 1985 and 1996, the current population is estimated at approximately 30,000 breeding pairs (Baker 2003, pers comm.), making it one of the most important and possibly the largest colony of red-footed boobies in the world. Although the red-footed booby is the most numerous booby species in the world, most populations are threatened by habitat destruction and feral animals (Marchant & Higgins 1990).