A cold front was forecast to come through by midday, bringing an especially mild autumn to an abrupt conclusion. I dislike cold weather and was taking the change of seasons personally.

I moved a little more slowly than normal. My arthritic joints are more certain predictors of the change in weather than any meteorologist could hope for. My crankiness was checked, though, when I noticed a slender, dark sparrow land on the deck railing.

In the Washington, D.C. area, the dark-eyed junco (Junco hyemalis) is a winter bird. Certainly snow geese and tundra swans are more dramatic harbingers of winter, but around here the junco is a just as reliable sign of cold weather.

Many migratory birds are weather experts, and the junco is no exception. They take advantage of fronts, and ride the leading edge of weather systems, flying ahead of the storms with strong tail winds, which speed the birds to more favorable climates. The phenomenon is in evidence during both spring and fall migrations, and avid birders pay close attention to weather systems to capture maximum viewing opportunities.

My glimpse of the junco on this change-of-seasons morning was not the result of any such methodical approach. I was getting ready for work, not thinking of avian migration patterns. The junco's arrival forced me to smile: It seems that not all of the world's creatures have the dim view of cold fronts that I do.

Dark-eyed juncos come in at least six distinct subpopulations. The male bird on my deck was of the "slate-colored" variety. His eponymous black eye was circled by jet black feathering. Head, breast, back, wings and tail were all a rich slate gray. His white stomach and tail, when viewed from below, were bright white. His counterpart female is grayish brown overall. It is the only kind of junco reliably seen in the Chesapeake region. Other subpopulations of dark-eyed juncos spread across the continent. They share certain characteristics. All have pink bills, white bellies, and well-defined white feathers on the outer edge of their tails.

They may all be the same species, but the other subpopulations of dark-eyed juncos add real diversity. They can come with black hoods, rusty sides and brown wings, or pale gray bodies with white wing bars. They can be wide-ranging or geographically limited. In other words, they are a lot like people: They come in a variety of colors but are all the same species.Â

Most slate-colored juncos nest and breed in the conifers of Canada. They are short-distance migrants, heading south and down out of the highest elevations every winter. Interestingly, their migrations are marked by a distinct pattern of behavior linked to the bird's sex.

Females travel farthest south, avoiding the worst weather. Older males don't generally head that far, while young males have the shortest migration of the species. Ornithologists theorize that the young males want to remain close to breeding grounds next spring because they will have a tough time competing for nesting territory. Older males, who will aggressively defend their old turf, don't have the same worries. And the females aren't concerned about territory at all. When they return to Canada, they will have their pick of mates.

Sizable numbers of these seed-eating birds can be found year-round in the cooler parts of the Chesapeake watershed such as the Shenandoah Mountains and Pennsylvania. Some of the birds head south during the winter only to be replaced by cousins from farther north. The birds appear to be year-round residents, but the actual individuals in a "resident" area may vary significantly.

During the winter, dark-eyed juncos congregate in a variety of Chesapeake locations, from suburban lawns and parks to mixed forests and farm fields; even a backyard inside the Washington beltway.

The advancing cold front had made its presence felt in my joints, but to a junco, it was just the express train to a suitable winter habitat. Our "bad" winter weather is a relative thing. For the junco, food is plentiful in our trees and well-stocked bird feeders. The large pines that form our northeastern property line serve as shelter and safe haven.

In this winter of discontent in political Washington, D.C., it was refreshing to see these friendly visitors who seem immune to the icy climate. The dark-eyed junco sitting on my porch reminded me of the obvious: Not everyone hates cold weather.

I put on a warmer sweater. My joints were still unhappy, but perhaps the change in weather wasn't the personal assault it seemed a few minutes ago. Maybe it's just a cold front after all, bringing back a flock of friends that love to winter in the mid-Atlantic.