Answer:
While I am sure that some sociological discussion of scientists has led someone to produce a list of traits or skills that a scientist must have, there is certainly no fixed and reliable list where you can enumerate skills.
There is perhaps one skill that would be broadly agreed upon and that is a skill in critical thinking. By critical thinking, one means essentially being sure of what you know and being able to put together the reliable implications of what you know, while recognizing that there are potentially relevant factors that you may not know.
Wikipedia has a nice entry on critical thinking.
And, one last comment, critical thinking may be required of a scientist but it is not limited to scientists. Presumably this is a valuable skill for anyone.