What I found perhaps most eye opening, however, was a statement that in terms of survival, the nonbreeding period is the more critical period of the annual cycle. Aggressive behaviour results in an unequal disposition of the resources, with dominant individuals having priority of access - and in some species, dominant individuals have greater survival probabilities than subordinates.
So in all, behavioral dominance in winter can result in the dispersal of birds into an "optimal habitat" in which dominant birds have a relatively high survivorship throughout the winter, and a sub-optimal "fringe habitat" inhabited by subordinate birds that have comparatively low survivorship through the winter.
This situation does seem to epitomize the idea of "survival of the fittest" - these birds may be continuing conflict even in the "off season" just to maintain their dominance and ability to maximize the resources available to them - and thereby, increase their reproductive fitness as well come the breeding season. And the cycle comes full circle - what is done out of breeding season ultimately also affects your offspring.
Fascinating!