Final answer:
The bird's brain controls its behavior patterns, intelligence and complex behaviors, navigation, mating, and nest building. While feet and beaks are adapted to specific environments and food sources, the brain governs the actions and reactions necessary for a bird's survival and reproduction.
Step-by-step explanation:
The part of the bird that controls behavior patterns, navigation, mating, and nest building is called the brain. Birds have a large brain relative to their body size, which is particularly developed for flight. However, the brain is also responsible for their intelligence and complex behaviors, such as using tools, planning, cooperation, and their remarkable mating rituals. For example, bird displays during mating can be quite elaborate and are crucial for attracting a mate.
Additionally, birds have other innate behaviors controlled by their brain. An example of this is the instinctive behavior seen in chicks, such as gaping when their mother returns to feed them. Birds' feet and beaks are adapted for their habitats and what they eat, but it is the brain that allows them to exhibit complex and intelligent behaviors