The skeletal system of birds differs from that of reptiles or mammals. This is due to the adaptation of these animals to flight. Several bones are pneumatized by diverticula of air sacs associated with the respiratory system including the sternum (Claessens, 2009;Koenig et al., 2016).Phylogenetically, birds have evolved from dinosaurs over 100 million years ago and the groups of birds explosively diversified, nowadays being registered more than 10,000 species being registered, distributed all over the globe, being adapted to diverse ecological habitats, lifestyle, and ranging in size from the tiny bee hummingbird (∼2 g) to the ostrich (∼140,000 g) (
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