Conflict, in turn, produces another problem: how to win or lose without the disagreeing parties incurring too great a cost. This latter point is particularly important. Imagine that two birds engage in a squabble about a desirable nesting area. The interaction can easily degenerate into outright physical combat. Under such circumstances, one bird, usually the largest, will eventually win-but even the victor may be hurt by the fight. That means a third bird, an undamaged, canny bystander, can move in, opportunistically, and defeat the now-crippled victor. That is not at all a good deal for the first two birds. Conflict-and Territory Over the millennia, animals who must co-habit with others in the same territories have in consequence learned many tricks to establish dominance, while risking the least amount of possible damage.