Final answer:
The brain stem is the region of the bird's brain that regulates heart and respiratory rates.
Step-by-step explanation:
The brain of a bird has a region called the brain stem that regulates heart and respiratory rates. The brain stem is composed of the midbrain, pons, and medulla, which control the cardiovascular and respiratory systems. Within the medulla, there are nuclei referred to as the cardiovascular center, which controls the smooth and cardiac muscle of the cardiovascular system.