How are unwitnessed behaviours (such as an adult bird building a nest the chick never saw the construction of) passed onto the next generation?

Question

How are unwitnessed behaviours (such as an adult bird building a nest the chick never saw the construction of) passed onto the next generation?

In: 7354

Answer 1

I don’t think this question has been answered yet. Yeah, it’s “instinct” but how exactly does that work? My go to example is spider webs. Those are deliberately built in a specific way with no instruction from the elders.