The Mafia group of islands lie 25 km off mainland Tanzania, virtually opposite the Rufiji Delta (TZ032). They consist of the main island and a number of much smaller islands and islets. They are essentially all coral rock islands with some of the smaller ones nothing more than a sandbank at low tide. The coastal bush vegetation has been largely replaced by coconut plantations and small-scale agriculture. The vegetation was heavily degraded as long ago as the 1940s and only small patches of coastal forest remain.
See Box for key species. The islands are known to hold at least 154 species. They are particularly important for Dromas ardeola with 500–1,000 birds recorded at Chole Bay in 1997 and 1998. The site also holds good numbers of Tringa cinerea, Pluvialis squatarola and Calidris ferruginea. Sterna bergii occurs and Sterna dougallii used to breed on the smaller islets and may still do so. The local breeding population of Ardea goliath on coastal islets is worthy of note. The race Cercotrichas quadrivirgata greenwayi is endemic to Zanzibar and the Mafia islands. Centropus superciliosus loandae are common on Mafia island and appear to breed alongside smaller numbers of the black-capped Centropus superciliosus burchelli.
Non-bird biodiversity: The area has, until quite recently, been an important breeding ground for sea-turtles. However, the levels of poaching for meat and carapace have increased far beyond any sustainable offtake. A newly described toad, Stephopaedes howelli, has been found in the remnant coastal forest.
BirdLife International (2019) Important Bird Areas factsheet: Mafia Island. Downloaded from http://www.birdlife.org on 12/12/2019.