From where I sit at the living room window, I like the light of autumn best of all. It’s bright but not blanching, soft but not sullen, filling the room in a way that makes me want to stay there awhile, even when I have much to do.

I was sipping coffee on the sofa, watching the sun pour in and gather in a small pool of gold where the dog would come and rest as if it were a bed made just for him, when I noticed a small blemish on the window pane. It was a dark smudge of the sort my children once left on doors and counters and doorknobs when their hands were tiny and full of jam.

It seemed ungrateful, somehow, to focus on the little stain on a window otherwise flooded with fall light on a day that looked like the backdrop of an L.L. Bean catalog. But the blotch, once noticed, quickly became all that I could see. My thoughts turned to Virginia Woolf, who once wrote an entire story, “The Mark on the Wall,” about a character who becomes mentally consumed by a spot he notices in a quiet room. The story is about a few things, including our silly human capacity to be carried away by the slightest claim on our attention.

I thought about my own foolishness in concentrating on something so insignificant, but my preoccupation got the best of me. I went to the window to more closely inspect what was irritating my senses, like a seed caught in the teeth.

The stain, I discovered, was blood. A bird had banged its head on the window, oblivious to the glass, and now lay just beyond the sill on the front porch, perfectly still and perfectly dead.

The bird was still fresh, but it took me a few moments to clearly identify him, although I’m familiar with the common species. He was a mockingbird, but death quickly abstracts a wild thing, and what you see is really just an odd husk of the familiar, fluttering creature that once looked exactly like its picture in the guide book.

What I noticed first was how much the true quality of a bird rests in the quickness of its eyes, and how dull and anonymous the poor thing becomes when its eyes glaze like the slits of a mask.

I fetched a dustpan from the closet, collected the corpse from where it rested by the front porch rocker, then set the bird beneath an azalea at the far corner of the lawn.

Finishing my coffee, I thought about the peculiar alchemy that would make the bird into food for the shrubbery. Something that once flew high among the trees, restless and beautiful and elusive, would now grow somehow into something green and silent and rooted in place.

I didn’t plan to think about any of this when I sat in front of a window warmed by sun on a morning made to order from an ample autumn stock of perfect days.

But as Halloween reminds me each year, fall sometimes finds its beauty in shadows we’d never go to seek.

Danny Heitman is on Twitter, @Danny_Heitman.