system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How are unwitnessed behaviours (such as an adult bird building a nest the chick never saw the construction of) passed onto the next generation?
gpt
Nest building is a species-specific innate behavior, birds don’t learn how to build a nest, they’re born with an instinctual drive that lies in their genetics. It’s also why different species make different types of nests which be radically different in construction. 

For a contrast, brown bears are NOT born knowing how to fish, they have to both learn from their mother by watching her, and also they develop their own unique style. Each bear fishes in slightly different ways, some like to wait under the water, others prefer to wait at the top of a fall for a fish to practically leap into their mouths, others wait behind the boil of the fall to pick up fish that failed the jump, some use jaws first and others use paws.