Welcome to EvC Garabato. Thanks for joining us.
I think it would help people answering your question if we knew more about what you already understand or don't understand.
Perhaps you can explain more what your view and understanding is.
My reason for asking for this is particularly this sentence:
How did that incubation method probably evolved? If the young birds didn't had the ability to dig up then they would have becomed extinct as the mother burried into the ground; but the ability to dig up would be useless otherwise.
This hints that you know nothing at all about the evolutionary model. If that is the case you might to better to ask questions of a more general nature. Then you should find this question very easy to answer yourself.
You can find a number of other questions just like this one. They often involve things like how can a symbiotic relationship develop, how can sexual organisms arise (often asked like this: "how can a male appear if it has no female to mate with) and so on. In all cases the answer is, at a high level the same and when you have just a beginners understanding of evolutionary science you will be able to answer it.
As a clue: think gradual.
You can add more to your opening post (OP) and then reply to me and I will consider what you have then. Or you can leave this and ask questions in other threads.
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