'White Finches evolved to be Black' : is ANY of this true ?

Well 'finches' are 'finches' - we'll let that semi-accurate layperson definition stand, for the sake of argument.

But did all the white finches, as gradually as Darwin claimed they must, all turn into black finches ?

But might it really be that most finches used to white and now - currently and only here and not there - most are black ?