What is a bird?

"Relations entre la classe des reptiles et celle des oiseaux qui en serait issue au cours de l'évolution. Reconstitution artificielles démontrant l'adaptation de toute l'anatomie de l'oiseau au biotope et au vol. Expériences de laboratoire sur le mécanisme déclenchant et réglant la migration."
"Traces the evolutionary relationship between birds and reptiles, and explains how the bird's skeletal structure gradually adapted to the requirements of flight. Uses close-up photography, animated drawings, and laboratory experiments to show that birds are able to live in a wide variety of environmental niches because of their behavioral instincts and the adaptations of structural features."@en
"Traces the evolutionary relationship between birds and reptiles, and explains how the bird's skeletal structure gradually adapted to the requirements of flight. Uses close-up photography, animated drawings, and laboratory experiments to show that birds are able to live in a wide variety of environmental niches because of their behavioral instincts and the adaptations of structural features."@en
"Summary: Shows the evolutionary relationship between birds and reptiles. Explains how the body structures of birds are adapted for flight. Also discusses the ability of birds of surviving in a diversed environment because of their behavioural instincts and the adaptations of structural features."