Basis for a Forbidden Item - When is the Rule of 'Migo D'Itkatzai' Applied

Hello, I wanted to ask about the rule of basis for a forbidden item, which states that it is forbidden to move the basis even after the muktzeh has been removed from it, due to the rule of 'migo d'itkatzai'. What is the law in a case where it was possible to blow the muktzeh off at any time with one's mouth or move it using a permissible item for the sake of its place (according to the Taz, this is considered as moving from the side)? Is it considered as 'gomro b'yade adam', and at least will it be permitted after the muktzeh has been removed, since it could have been permitted not to be considered a basis at any time (unlike a candle which is forbidden due to extinguishing), even if we say that the rule of 'gomro b'yade adam' does not apply to a basis, at least there will not be the rule of 'migo d'itkatzai'. Thank you very much!!!

Hello 

In several places, it is explained that even if it was possible to blow it off during twilight, it becomes a basis. 

See sources. 

In Shulchan Aruch, Orach Chaim, Siman 308, סעיף 39: It is forbidden to move an animal, wild animal, and bird; nevertheless, it is permitted to cover the basket before the chicks so that they can go up and down on it, and while they are on it, it is forbidden to move it.

And the Mishnah Berurah writes (there, סעיף קטן 148) It is forbidden to move - and if they were on it during twilight, it is forbidden even if they descended, due to the rule of 'migo d'itkatzai' during twilight, it is forbidden for the entire day:

It is explained that although on Shabbat this is not considered nullifying a vessel, since it can be immediately blown off, it is considered muktzeh if they were there during twilight. 

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