The diet and ecology of Hawaii's extinct flightless waterfowl: evidence from coprolites

At least five species of large flightless waterfowl have become extinct in the Hawaiian Islands in recent millennia. These birds are thought to have occupied the role of large herbivores in a wide range of terrestrial habitats. A collection of coprolites from one of the species (Thambetochen chauliodous) was obtained during excavations in Holocene cave sediments on the island of Maui. The chemical composition and pollen and spore content of the coprolites are analysed and compared with pollen/spore spectra from the cave sediments and from recent goose scats. The results support the contention that these birds were primarily folivorous, and further suggest that ferns were important in the diet. The coprolites have a very fine texture that may result from efficient hindgut fermentation and digestion of plant fibre. Our data are discussed in the light of a recent hypothesis of plant/herbivore coevolution between extinct avian herbivores and native Hawaiian lobelias. The loss of large native herbivores, as well as other changes in vertebrate trophic structure due to extinctions over the past few thousand years, may still be affecting ecological processes in areas of the Hawaiian islands with native vegetation.