Many Seychelles warblers of breeding age forgo breeding, remaining instead with their parents and helping to raise their own siblings  This behavior, called cooperative breeding, results from the scarcity of nesting territory for the birds on the tiny island that, until recently, was home to the world' s population of Seychelles warblers
Yet when healthy warblers were transplanted to a much larger neighboring island as part of an experiment, most of those warblers maintained a pattern of cooperative breeding
Most of the terrain on the neighboring island was not of the type in which Seychelles warblers generally build their nests.