Observations on the habitat preference and physio-morphological traits of the Red-footed Booby (Sula sula) at Mobulau island, Fiji

The habitat preferences and physio-morphological traits of the Red-footed Booby (Sula sula) were studied at Mobulau island, Fiji. Mobulau island lies on the southeast coast of Viti Levu, near the mouth of the Rewa river. Ecologically, the uninhabited tropical rainforest island provides ideal conditions for colonization by the Red-footed Booby, as well as the Brown Booby and resting sea snakes. The estimated population of S. sula on the island was 200 – 250 birds. These birds shelter, brood and raise their chicks on the top of tall trees. When approached, birds appeared unaware of humans and did not fly. However, swift, aggressive movement of their long beaks (11cm) was observed and this appeared to be the primary defense mechanism of brooding parent birds on their nests or with their chicks. Observation of 20 nests showed a single egg with brooding parent. All nests were found against the windward direction and made up of twigs and leaves. These well-constructed nests were oval in shape, about 20cm in diameter and about 5 – 10m from the ground. The coastal side nests were at a lower height than that of the inland nests. Body measurements and blood values are also discussed. The physical structure of an island prevents the human colonization and consequently the island is an ideal site to study the sea Booby in the South Pacific.