Document ID: chunk:federal_register_of_legislation:F2022L00775:reg:18:p84
Version: federal_register_of_legislation:F2022L00775
Segment Type: reg
Provision Reference: reg 18 (pt 84/152)
Character Range: 272134–274948

Wildlife Conservation Plan for Seabirds 117
Species profiles

Brown Booby (Sula leucogaster)

Life History and Distribution
The Brown Booby (Sula leucogaster) is a medium sized, sleek looking dark-coloured booby with sharply demarcated brown and white underparts. The Brown Booby can be found throughout the pantropical oceans with few exceptions. Breeding sites include the Caribbean, the Atlantic coasts of Brazil and Africa, oceanic islands off Madagascar, the Red Sea, northern Australia, many oceanic islands in the western and central Pacific, as well as off the coast of Mexico and Peru. Breeding is seasonal in some areas, but elsewhere it breeds opportunistically or more or less continuously. Nests are built on the ground in the midst of vegetation on rocky islands or coral atolls. Individuals form colonies that are usually smaller than those of other Sula species (del Hoyo et al. 1992). This species is strictly marine, generally feeding on inshore waters. Its diet is comprised mainly of flying-fish and squid, but also some halfbeak, mullet and anchovy. Prey is usually caught by plunge-diving and it can also snatch prey off the surface of water. Kleptoparasitism has been observed, mostly by females.

Population Estimates and Trends
The global population is estimated to number > 200,000 individuals (del Hoyo et al. 1992). Globally, the population is suspected to be in decline owing to disturbance and unsustainable levels of exploitation. Numerus breeding locations occur on offshore islands in the Great Barrier Reef, Coral Sea Marine Park and north-west WA. Survey data suggests Ashmore Reef Marine Park accounts for ≥1 per cent of the global population (Cannell and Surman 2020). Several thousand pairs also breed on Christmas (5,000 pairs) and Cocos (Keeling) Islands. The total Australian population and trends are unknown.

Conservation Concerns and Actions
Brown Boobies are hunted for food and bait in some areas of their range (del Hoyo et al. 2019); however, this is thought to have negligible effects on their population. They are highly sensitive to human disturbance, with the presence of humans 10–20 m from the nest enough to cause the birds to leave (Borsa et al. 2010). Verlis et al. (2014) found that most Brown Booby nests surveyed contain at least one item of marine debris. Further, Lavers et al. (2013) found that around 30 per cent of the debris poses some entanglement risk to the birds. This is currently unlikely to represent a significant source of injury and mortality (Lavers et al. 2013) but is likely to increase due to the long term persistence of marine debris. In the past, organochemical pollution has caused a significant reduction in reproductive success due to the thinning of eggshells, often caused by DDT use in agricultural areas as well as, in