It is a shallow island surrounded by mangroves and tidal flats containing one of the country's last remaining coastal forests.

[2] It is located about 0.5 kilometers (0.31 mi) from Casuarina Point and forms the northeastern side of Mantaquin Bay.

In order to protect this bird species whose number dropped sharply from as many as 4,000 in 1994 to only about 1,000 in 2001 due to illegal poaching and rapid deforestation of its coastal environment, the Philippine government declared the whole island and surrounding waters a bird sanctuary known as Rasa Island Wildlife Sanctuary.

[3] The 1,983-hectare (4,900-acre) bird sanctuary is now administered by the Department of Environment and Natural Resources in partnership with the Philippine Cockatoo Conservation Program of the Katala Foundation.

[1] A number of other endemic birds have also been observed in the island such as the blue-headed racket-tail, grey imperial pigeon, Chinese egret and Mantanani scops owl.