São Tomé Island, at , is the largest island of São Tomé and Príncipe and is home in May 2018 to about 193,380 or 96% of the nation's population. The island is divided into six districts. It is located 2 km (1¼ miles) north of the equator. Geography São Tomé Island is about long (north-south) by wide (east-west). It rises to at Pico de São Tomé and includes the capital city, São Tomé, on the northeast coast. The nearest city on mainland Africa is the port city of Port Gentil in Gabon located to the east. The island is surrounded by a number of small islands, including Ilhéu das Rolas, Ilhéu das Cabras and Ilhéu Gabado. Languages The main language is Portuguese, but there are many speakers of Forro and Angolar (Ngola), two Portuguese-based creole languages. The name "Sao Tome" is Portuguese for "Saint Thomas." Geology The entire island of São Tomé is a massive shield volcano that rises from the floor of the Atlantic Ocean, over below sea level. It formed along the Cameroon line, a line of volcanoes extending from Cameroon southwest into the Atlantic Ocean. Most of the lava erupted on São Tomé over the last million years has been basalt. The youngest dated rock on the island is about 100,000 years old, but numerous more recent cinder cones are found on the southeast side of the island. Environment and economy The higher slopes of the island are forested and form part of the Parque Natural Obô de São Tomé, but agriculture is important near the north and east coasts. The chief exports are cocoa, coffee, copra, and palm products, while there is also a fishing industry. Large reserves of oil are in the ocean between Nigeria and São Tomé. The discovery has been lamented by some as endangering the nation's political stability and natural environment. In response to these concerns the government of São Tomé and Príncipe has drawn up legislation in an attempt to ensure the efficient and equitable use of oil revenues over time. Natural history Birds The island has a total of 63 regular bird species, plus an additional 36 vagrant and unconfirmed species. Of these, 19 are endemic and 3 near endemic; in addition, the local subspecies of olive ibis (Bostrychia olivacea bocagei) and maroon pigeon (Columba thomensis) are endemic and considered critically endangered. Six species are considered vulnerable, and two critically