The Diet of Early Birds Based on Modern and Fossil Evidence and a New Framework for its Reconstruction

Molecular phyloecology suggests a trophic shift concurrent with the evolution of the first birds

“…Fossil evidence shows that ever since the origin of birds (Aves: defined herein as the clade including Archaeopteryx and modern birds, as proposed previously [1][2][3] ) from the Late Jurassic, they had undergone adaptive radiation to diversified dietary niches in the Cretaceous, with herbivorous (e.g., fruits and seeds), piscivorous, and insectivorous diets found [3][4][5][6][7][8][9][10] . In particular, seed and/or fruit eating are suggested in many ancestral bird lineages, such as Jeholornis, Confuciusornis, Sapeornis, Hongshanornis, and Yanornis [2][3][4][5][6][7][8][10][11][12][13] . This suggests that seed and/or fruit eating may have been relatively common during the early evolution of birds, and that this herbivorous adaptation may play a vital role in the early evolution of birds 5,11,14,15 .…”