Evolution of avian breeding strategies and its relation to the habitat preferences of Mesozoic birds

Birds are the only extant tetrapods, which incubate their eggs with body heat in nests outside of soil. Nesting free of sediment is now considered to have evolved comparatively late in avian evolution, within Ornithuromorpha, the clade including modern birds. Egg turning by the breeding adults was identified as an evolutionary corollary of this derived reproductive behavior and is due to a higher albumen content of the egg. An associated...