When the leaves have all fallen and the days get really cold, it is time for the black-capped chickadees to take charge.

As the season shifts, chickadees gather in small flocks - no longer flying alone - and become the nucleus for what will soon become larger flocks of mixed species. These flocks will define the winter woods and remain together searching for food until spring.

During the winter, the flocks primarily consist of chickadees and titmice, with white-breasted nuthatches and downy woodpeckers complementing the central core. These birds follow the chickadees because the chickadees are excellent at finding food.

Frequently, migrating species at stop-over sites follow the chickadees around for the same reason; they know that the chickadees can locate food better in native territory. The migrant species benefit considerably by doing this because they also gain protection from predators. Chickadees are not only very good at finding food, they are also outstanding at spotting danger.

Thus, migrants benefit from foraging with chickadee flocks by decreasing the time they spend on vigilance and increasing their feeding rate. They are, it would seem, exploiting the chickadees as sentinels, but the chickadees probably benefit too by strength in numbers.

Chickadee warning calls are extremely sophisticated. To the human ear, one chickadee call sounds like any other, but hidden variations in each call carry important information. When a predator enters the feeding area or is circling high above the woodlot, the call of the chickadee can relay the nature of the threat, whether it is from the air, a perch or coming in fast through the trees. The migrant follows the flock and avoids the danger.

During November, birders can take advantage of this behavior and discover many uncommon migrants simply by following chickadees around. Recently, I noticed a band of chickadees working the branches of a black birch in my back woodlot. Closer examination revealed five yellow-rumped warblers mixed in with them. Further up the tree an unusual woodpecker caught my eye, which, after several minutes of observation, turned out to be a yellow-bellied sapsucker.

I have used this strategy for many years and the most common tagalong seems to be the golden-crowned kinglet. In fact, I rarely encounter this bird any other way. They spend most of their time high up in conifer trees, but during migration they reveal themselves while feeding with the chickadees. Their hyper-activity and extremely small size make identification easy. Downy woodpeckers, red-breasted nuthatches, brown creepers and various warblers also follow the chickadees.

It is easy to follow these flocks as they visit the feeder. Very rarely do you see titmice, nuthatches and downy woodpeckers at the feeder without the chickadees nearby keeping an eye out for danger. In fact, some studies show that the white-breasted nuthatch will not land on a feeder without a chickadee doing so first.

So, keep your eyes on the trees around your feeders for those less common followers. The black-capped chickadee may be a common bird we tend to overlook, but following them is a rewarding strategy for finding birds.

Robert Tougias is a birding author who lives in Colchester. He is available for presentations and will answer your questions at rtougias@snet.net.