Here's why:

* Instinct refers to a complex, unlearned pattern of behavior that is present from birth and is characteristic of a species. It's a built-in, automatic response to certain stimuli.

* Learned behavior, on the other hand, is acquired through experience and interaction with the environment.

Examples of instincts:

* Birds building nests: This is a complex behavior that is innate and not learned.

* Spiders spinning webs: Spiders are born with the knowledge and ability to spin webs, even without ever seeing another spider do it.

* Salmon migrating upstream to spawn: This is a complex instinctual journey guided by internal biological cues and environmental triggers.

Let me know if you'd like more examples or want to discuss specific instincts!