I also wonder whether they can work in teams. For that matter I wonder if chimpanzees and crows (the other "tool users" mentioned in the article) work in teams.
Interesting stuff.
Interesting stuff.
From what I've learned about evolution, and "selfish gene" theory, it seems as though cooperation pervades social animal societies. According to this page [1], and the Wikipedia article on rooks, they seems to flock together. I wouldn't be surprised if further study reveals some cooperative behaviour.