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Nest building by Darwin’s finches as an overlooked seed dispersal mechanism

Published online by Cambridge University Press:  11 December 2018

Carlos Camacho
Affiliation:
Department of Evolutionary Ecology, Estación Biológica de Doñana – CSIC, Av. Américo Vespucio 26, 41092 Seville, Spain
Marc-Olivier Beausoleil*
Affiliation:
Department of Biology and Redpath Museum, McGill University, 859 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6
Julio Rabadán-González
Affiliation:
Observado.es, Gordal 8, 41940 Tomares, Seville, Spain
Roxanne Richard
Affiliation:
Department of Biology and Redpath Museum, McGill University, 859 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6

Abstract

Caliochory, or seed dispersal by birds as nest material, has been reported for several species, but its effectiveness remains unclear in most cases. Darwin’s finches are traditionally regarded as seed predators, but the observation of two nests challenges this assumption by demonstrating that they can act as seed dispersers via caliochory. Darwin’s finches incorporate cotton-like materials into their nests, including seeds of Darwin’s cotton (Gossypium darwinii), a shrub endemic to the Galápagos (Ecuador). Bird nests typically break down after intense rainfall, so the seeds incorporated into nests might benefit from suitable conditions for germination. By simulating the germination conditions experienced over a 72-h period by cotton seeds in a naturally fallen nest, this study qualitatively confirms the long-term viability of at least a small fraction of the seeds at the surface of the nest. Darwin’s finches might therefore provide seed-dispersal services to Darwin’s cotton and possibly, other native and exotic plants of the Galápagos commonly incorporated into nests. However, larger confirmatory studies are needed.

Type
Short Communication
Copyright
© Cambridge University Press 2018 

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References

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