The work of the bird in building its nest shows more continual steady effort tham most humans in their buliding plans.
This is quote from an essay about the difference of the works between animals and humans. My question is about their buliding plans. their means humans and the subject of the gerund building, building is a grrund not a present participle, and plans like in buliding its nest bilding is a gerund, juxataposition. So it means their finishing plans not their construction plans.
Thank you very much
I think you are, though it is not a very well-written sentence as it is very easy to interpret it as 'construction plans'.