List the adaptations of birds to flight.

The birds are ideally adapted to flight: – modified forelimbs – wings; – the flying plane is formed by contour feathers; – streamlined body shape, increasing due to the pointed beak; – long nostrils on the sides of the beak; – bones with air cavities; – outgrowth of the sternum – keel; – the bones of the foot are fused into the tarsus; – tail spine – tailbone; – air bags – “double breathing” in flight; – fast digestion and frequent bowel movements; – no bladder.