Wedge-tailed Shearwater chicks also known as Mutton Birds were collected and sold as a food source on neighboring islands and turtles were killed for their shells and meat – these actions all resulted in a depletion in the numbers of these species. Natural habitat was cleared to make space for a Casuarinas plantation, the wood was taken by pirogue to the larger islands and sold as fire wood, a coconut plantation was added and livestock and poultry was kept as a source of food for the islanders.

1972 – 1974: Plans were drawn up to build 3 apartments on the hill.
1975: Blasting on the hill with dynamite was carried out in order to move rocks and to clear areas for the apartments. After the blasting was carried out the Seychelles Brush Warbler disappeared from Cousine. This species was reintroduced in the early 80’s and is now thriving.

1976: The 3 apartments on the hill were completed.
The ownership of the island changed many times from Seychellois to foreigners back to Seychellois and in 1970 it was sold to 3 Swiss-German businessmen before it was finally bought by the present owner in 1992.

Since 1992 extensive habitat restoration was carried out, more than 4000 trees have been planted on the plateau; Giant Tortoises were rescued from neglect and released to roam freely on the island. Between 1993 and 1996 the Seychelles Magpie Robin was introduced. In 2000 the Sooty terns returned to breed on Cousine after being absent for more than 30 years. In 2007 the Seychelles White-eye was introduced.