Document ID: chunk:federal_register_of_legislation:F2007B00392:body:0:p10
Version: federal_register_of_legislation:F2007B00392
Segment Type: other
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Character Range: 23796–26667

Bennett pers. comm.). However, as of May 2003 there are no Christmas Island Frigatebirds nesting in the area where the old dryers colony was.

Storms
Christmas Island tends to be affected by severe storms every five to ten years. The small population size and limited breeding distribution mean that chance events such as severe storms could have marked effects on breeding success and possibly survival of juveniles and adults. It is known that many eggs can be destroyed in strong winds (Marchant & Higgins 1990).

Fire
Although fires are uncommon on Christmas Island, they did occur in terrace forests during a long dry season in 1994, and again in terrace forest in September 1997. Terrace forests can become extremely dry during the dry season and a fire could have devastating effects on breeding areas. The limited area of the nesting colonies makes them especially vulnerable to fire. The Cemetery and Golf Course colonies are close to human activity, which substantially increases the risk of wildfire in those areas.

Disease
A serious threat to all island birds is the introduction of new disease, particularly when the populations are small. Island birds have often evolved in the absence of diseases common in continental bird faunas and the introduction of such diseases to island birds can be disastrous. An example of this is the introduction of avian malaria to Hawaii which caused the extinction of almost the entire endemic bird fauna from below 600 m altitude, and was probably the main cause of the total extinction of several bird species (Hay 1986). The range of many surviving species was severely reduced and fragmented which in turn markedly increased their chances of extinction. Avian malaria arrived with the accidental introduction of a new species of mosquito (Hay 1986). Christmas Island has been very vulnerable to the accidental introduction of new disease. In 1994 a quarantine barrier was established between the island and Indonesia and Australia and this has reduced that risk.

Weeds
Weeds, especially newly introduced invasive species, could impact on Christmas Island Frigatebird nest sites, for example by forming vine towers over nesting trees.

Other Potential Threats
Sea-surface temperature was strongly correlated with average annual breeding success of Abbott's Boobies. It was hypothesised that cold water upwellings provided rich food resources (Reville et al. 1990). Higher sea-surface temperatures predicted as a result of global warming could reduce food availability in marine areas adjacent to Christmas Island.
Currently there is very little information on the areas in which Christmas Island Frigatebirds forage. It is likely that over-fishing is a potential problem in some of the foraging habitat of Christmas Island Frigatebirds.
Domestic cats could also pose a potential threat to grounded birds, especially in