How?
What was the mechanism of this adaptation?
If they look the same (i.e. ‘like a vulture’) because they “adapted the same way to the same environment” - then it follows logically that previously they did not look the same (i.e. ‘like a vulture’).
So if we are to accept YOUR reasoning that they look the same because they adapted the same way to the same environment - then two different bird populations adapted the same way to the same environment through adaptations that MADE THEM LOOK LIKE VULTURES.
And once again, speciation is not a case of a non vulture giving birth to a vulture in one generation (as only one unlearned in biology would have it).
So what mechanism would cause these two populations to look the same through adapted the same way to the same environment? And what would you call them BEFORE they adapted the same way to the same environment?
The fossil record does not support the idea that evolution happens slowly over long periods of time. You need to go back to school and learn about punctuated equilibrium. Darwinists now claim that evolution happens quickly after long periods of equilibrium, so yes the non-vultures would have to have become vultures quickly, because that's the only way it possibly could have happened without leaving any fossil evidence of this alleged transition. Darwinists are always having to change their theory because the evidence is always proving Darwinism WRONG. That's why you don't want to defend the idea of universal common descent, because even you know that there is no evidence to prove such a preposterous idea. So now you want to blur the distinction between natural selection and speciation, in order to muddy the waters and cause confusion, because people will only believe in Darwinism if they are confused about how it is supposed to work. I am not confused about how it is supposed to work because I studied biology and biological anthropology in college, so I know exactly how evolution is supposed to work. The more I came to understand the theory of evolution, the less I believed it. You want everyone to just accept your theory uncritically without thinking about it, because that's the only way you can fool people into believing that it's true.