Bird Island (558129 E, 38539 S) is the northernmost of the Seychelles archipelago,
around 100 km from Mahe´. Bird is a low coralline island (nowhere exceeding 5 m
above sea level), historically dominated by large seabird colonies; it still retains a
major breeding colony of sooty tern Sterna fuscata. In the early 20th century, the
island suffered major environmental change, with extraction of guano deposits in
1895–1906 followed by the planting of coconuts Cocos nucifera. By the 1970s,
coconuts dominated the island’s vegetation (Feare 1979; Stoddart and Fosberg
1981). The plantation ceased to be worked in the late 20th century, and was invaded
by woody species including Pisonia grandis. This widespread Indo-Pacific tree
species is disseminated by seabirds and, in Seychelles, is only abundant on islands
with nesting colonies of seabirds (Friedmann 1994); it is a major component of