Energy Metabolism, Gas Exchange, and Ventilation

Abstract The altricial precocial condition has traditionally been used to describe the morphological and behavioral characteristics of different species of bird chicks at the time of hatching (chapter 1). However, the ramifications of developmental mode reach far beyond the hatchling characteristics to affect such factors as energy and water density of the egg, ontogeny of metabolism, embryonic and hatchling growth pattern, and the parent birds’ time and energy budgets. Here we discuss the current state of knowledge about how the developmental mode appears to affect organismal-level energy metabolism, gas exchange, and ventilation in both the embryonic stage and the hatchling and nestling stages. Particularly for egg energy content and energy metabolism of the embryo, different developmental patterns and their correlations with the altricia precocial condition have been identified for some time (see section 4.2.2). For the hatchling and nestling stages, metabolism and ventilatory patterns and their correlations with the developmental pattern are only now emerging.