Earlier this week, I had a textbook perfect sighting of the most recognized symbol of the coming of autumn.

Although technically it is still “summer,” fall seems to have arrived early with chilly nights and brisk sunny days. Lately we also have had our share of the typical unsettled weather that heralds the change in seasons: sunny skies often clouded over in seemingly a matter of minutes, to be followed by passing showers and chilly breezes.

As I was driving home from work one evening, I was treated to a spectacular cloud display. Puffy white cumulous clouds billowed against the deep blue of the sky, and were replaced by low-lying nimbostratus that looked like it meant business. The sun shone unobscured from the west, and the golden evening light was a striking contrast with the dark clouds, making them glow and bringing out their deep slate gray hue at the same time.

Against this backdrop a skein of Canada geese appeared, flying low and rapidly. The evening light brought out the warm buff of their body feathers, which contrasted sharply with their black heads and necks; their characteristic white chin-cheek patch shone like a beacon.

This small group of geese was followed by another and another, lines of them snaking across the sky, coming in from the direction of the nearby Atlantic and heading toward the Fore River. It was a stirring sight.

Since I was driving and negotiating an exit ramp off the highway, I couldn’t dwell on the spectacle; and there was no place to pull over. As I drove on and left the geese behind me, I imagined hearing their trademark trumpeting calls.

A Canada goose’s call is unique, and one of the few ways to distinguish between males and females. The male’s call, lower in pitch, comprises two syllables — “ahonk”— and the female’s is higher pitched and one syllable — “hink.” A mated pair will sing these calls in a duet with one another, and in such synchronization that it sounds like the vocalizations are coming from only one bird.

It seems appropriate, then, that Canada geese mate for life. The young of each brood remain with their parents throughout their first year; family groups migrate together.

However, not all Canada geese migrate. I had always known there are large differences between the various groups of Canada geese, and one of them is that certain populations are nonmigratory. Others are differences in plumage lightness or darkness, and in body size.

I was interested to read in “The Birds of North America,” species account that The American Ornithologists’ Union considers some of the differences to be so significant that they’ve split the Canada goose into two separate species: the “cackling goose,” and the “Canada goose.” The “cackling goose” is of smaller body size, and the split is from other differences as well, such as voice, habitat and timing of migration, as well as on genetic studies.

I have to admit, though, when I see a “V” of geese arrowing across the sky, and hear their calls drifting down faintly from above, I don’t think about those things. I am more captured by the beauty and poetry of their existence.