Island Colonization by Lesser Antillean Birds

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Abstract
An analysis of the bird distribution on the small islands in the northern Lesser Antilles [West Indies, Caribbean Sea] colonized principally from Guadeloupe is presented. In spite of great differences among the islands in soils, rainfall and vegetation, their avifaunas are strikingly uniform. Species inhabiting coastal scrub on the source island performed better as colonists than inhabitants of interior rainforest, suggesting that humid forests in the target islands would hold drastically impoverished bird communities. Diversities in the small-island rainforest communities were compensated for by the substitution of coastal scrub species for missing forest counterparts and the expansion of vertical foraging zones. In progressing from species-poor to species-rich communities in equivalent habitats, the number of trophic guilds remains constant, while the number of species per guild and the tightness of species packing increase. The faunal uniformity of islands colonized from Guadeloupe results from nonuniform dispersal abilities coupled with ordering ecological constraints: versatility in habitat occupancy, trophic status and size in relation to guild neighbors.