Some of the general characteristics of class Aves:- They are genuinely flying vertebrate having feathered bipeds; modified hindlimbs are present which generally have scales; they not have a urinary bladder; they are uricotelic; minute, oval and nucleated erythrocytes are present; they are warm-blooded (homeothermic), and the heart is ultimately having four-chambered; they are oviparous. Dr Salim Moizuddin Abdul Ali was an Indian Ornithologist and Naturalist who worked for the conservation of endangered birds like "the Great Indian Bustard" by using his influence to gather the support of government for the organisation and created the Bharatpur bird sanctuary (Keoladeo National Park).