Final answer:
Birds have higher metabolic rates than mammals due to adaptations like pneumatic bones and efficient digestive systems which are necessary for flight. They lose heat quickly due to smaller surface areas and compensate by eating frequently and digesting quickly. Their closed circulatory system also contributes to their efficiency.
Step-by-step explanation:
The primary reason why reparation is more efficient in birds than in mammals, particularly when comparing with humans, is that birds have higher metabolic rates due to their physiological and anatomical adaptations for flight. These adaptations include having pneumatic bones, which are hollow and reduce body weight, making flight easier. They also have a highly efficient, simplified digestive system, with a two-compartment stomach optimized for quick digestion.
Birds require a high metabolic rate because they have smaller surface areas relative to their volume, which means they lose heat more rapidly. To compensate for this, and to fuel their energy-intensive flight, birds need to digest food quickly and consume greater amounts of food more frequently than mammals. Their closed circulatory system also plays a role in their efficiency, losing less energy to heat and being more effective in delivering nutrients.