Birdbrains, a term used to describe someone who is perceived as lacking in intelligence or common sense. However, there are several antonyms that can be used to describe the opposite of a birdbrain. Some of these words include intelligent, smart, wise, astute, clever, and shrewd. These terms describe individuals who possess a sharp intellect, quick thinking, and a strong level of common sense. They are often seen as knowledgeable and capable individuals who can handle complex situations with ease. Unlike birdbrains, these individuals can be relied on to make sound decisions and solve problems effectively.