Morphological Differentiation in Nestlings Turdus philomelos (Passeriformes, Turdidae) and Staging in their Development during the Nesting Period of Postembryogenesis

Abstract

Abstract The work demonstrates the clear presence of ageing aspects in the postembryonic development of the song thrush in regard to its linear dimensions and body proportions. It is proposed to distinguish the stages of early nesting, mid-nesting and late nesting. At each stage, the mostly developed body parts and organs are those which are needed for the growing organism to provide its best functionality at the current period of its postembryonic development.