
It's thought that a mixed flock like this benefits the members in a few ways. The many eyes and ears may be better able to find predators or food. Each species is able to take advantage of its own niche within the habitat while helping other members of the flock to locate food. We see this at our backyard feeders; curious chickadees are often the first species to check out a new feeder, followed closely by titmice, and finally the more wary woodpeckers. I've read that downy woodpeckers use chickadees and titmice as sentinels in a mixed-species flock. I also listen for their high pitched *seeee* notes to know that there's a hawk overhead.
The winter cliques will be breaking up before long as spring draws near and competition for territory and a mate becomes more important than the companionship of hungry friends. The demands of nesting and feeding a family must not leave time for much else. Until then, our familiar winter birds travel together and liven up the winter landscape with their whispered rumors of spring.