What are air sacs?
The respiratory system of birds is different from all other vertebrates. Birds have a lot of “empty space” inside them to keep them light for flying. These “empty spaces” are filled with clear, “glad wrap” bags of air, the air sacs. When a bird breathes in and out, it is not the lungs that are moving. A bird’s lungs are static. It is the air sacs that move and pump oxygen through a complex bronchial network of a stationary lung. Birds have nine main air sacs that play an important role in respiration. The avian respiratory system delivers oxygen from the air to the tissues and also removes carbon dioxide. It also plays an important role in maintaining normal body temperature. The respiratory system of birds is fast and efficient. It’s all an adaptation to allow for maximal absorption and delivery of oxygen to enable a bird to fly effectively. The unique respiratory system of birds is affected by many different physical and environmental conditions.
