Here's why:
* Kingdom: Plants belong to the Kingdom Plantae while birds belong to the Kingdom Animalia. These are two entirely separate kingdoms, meaning they have very different fundamental characteristics.
* Species: Species are even more specific. A species is a group of organisms that can interbreed and produce fertile offspring. A plant and a bird can't interbreed, so they can't be the same species.
In simpler terms: Plants are living things that make their own food through photosynthesis, while birds are animals that eat other living things for energy. They are fundamentally different types of organisms.
