It is part of nesting to find a good, sometimes strategic, location to nest in.
The nestplacing mechanic though, sometimes shatters those plans by denying a perfectly fine nesting spot for being not flat enough or simply ignoring rocks and placing the nest underground.
Especially the Bio, which has nests literally made out of sticky saliva, should have way more leniency when it comes to flatness or verticality of the surfaces.
Please make all nests more lenient with the surfaces and increase the flatness tolerance.
Also please let us nest on rocks, right now the nest is placed underground if attempting to nest on some rocky surfaces.