The crazy ant (Anoplolepis gracilipes) invaded Bird island, Seychelles, in the 1980s. In 1997, its range
expanded and population densities increased. The impacts of this change were studied in 2001 using a
combination of arthropod collecting methods. The ant population excluded larger invertebrates (principally
the large ant Odontomachus simillimus and the crabs, principally Ocypode spp.). Cockroaches, however,
remained abundant in ant-infested areas and tree-nesting birds (Lesser Noddy Anous tenuirostris) appear to
be able to breed successfully in the presence of the crazy ant. The ants are only abundant in areas of deep
shade which provide cool nesting areas, yet enabling them to forage in the open when ground temperatures
fall. The expansion of the ants was correlated with the regeneration of woodland on the island.
Recommendations are made for the management of the woodland which may reduce the impacts of the
crazy ant.