DID ORGANOCHLORINE PESTICIDE USE CAUSE DECLINES IN MAURITIAN FOREST BIRDS

We examine the hypothesis that organochlorine pesticide use in the 195 0s and 1960s caused population declines and local extinctions in two e ndemic Mauritian birds, the Mauritius kestrel, Falco punctatus, and Ma uritius cuckoo-shrike, Coracina typica. This hypothesis was suggested in the 1980s but is dismissed by authorities in Mauritius. The decline s and subsequent increases in the populations and range areas of both species, the timing and location of the use of organochlorines for mal aria control and in food crop production, the diets of the species, an d the known mechanisms for transfer of organochlorine residues into or ganisms are all consistent with the hypothesis. No alternative explana tion can at present account for these population changes. Organochlori ne pesticide use cannot therefore be rejected as a reason for the decl ines and local extinctions of the kestrel and cuckoo-shrike.