I read somewhere that pigeons normally live in little holes in cliffs, and that their "nests" are basically only supposed to prevent the egg from rolling out. So they are doing perfectly fine in their own way. In contrast to you and your stupid experiment.

It's enough to keep its egg from rolling away.

Edit: I was making a joke. I was surprised to learn from @KurtVonnegut@mander.xyz's comment that it's actually scientific fact.