A slight movement on the periphery of my vision alerted me to the wren before I fully realized he was there. A moment later, the clear, fluting notes boldly announced his presence. The Carolina wren (Thryothorus ludovicianus) is like that: a diminutive bird that might be overlooked except for an outsized song that commands attention.

It was one of those brutally hot and muggy August days that have been driving people out of Washington since the earliest days of the republic. We were visiting a friend on the western shore of the Chesapeake. The sun was setting, a light Bay breeze had arisen, and the cool drinks and congenial conservation had put us into a better frame of mind.

The birds were a bonus. Osprey swirled above and egrets and herons worked the shoreline. Meanwhile, gulls and terns soared over open water. The Carolina wren, which landed briefly on a patio chair, was looking for spiders and insects and reminding everyone that the backyard was his.

All wrens are small, and at just less than 6 inches, the Carolina wren can lay claim to being the largest of the wrens found in the eastern United States. They have that distinctive wren shape—a rather plump body with a slender, slightly down-curved bill and a tail that is often cocked straight up over its back.

In addition to its size, the Carolina wren is distinguished from its cousins by a bright white eye stripe set off in rich reddish-brown upper parts. The breast is a warm buff color that becomes somewhat darker on its belly. Dark barring is visible on the wing and tail.

These birds nest in virtually any cavity. Old woodpecker holes and other natural cavities in trees are prime locations. The wrens also nest in the roots of upturned trees, holes in stone or masonry walls, even unused watering cans and clothespin bags in the backyard. And, of course, bird houses. A few years ago, my brother and sister-in-law gave us a ceramic birdhouse in the shape of a tea kettle with a side entrance and a little chain to hang it up. It didn’t look like a nesting box, but it would make a nice accent piece in the flower garden, we thought. It has turned out to be a popular nesting site for backyard wrens.

The sexes look alike and jointly build the nest in less than a week. Females lay five to six eggs, which they incubate for about 14 days. Males feed the females on the nest. The chicks fledge in two weeks. Typically, a pair produces two broods each summer.

They are year-round residents throughout their breeding range, which extends from southern New England, across to the Great Lakes and south to Florida and Texas. Scientists who study global climate change and its effects on different species note that the range of Carolina wrens is extending northward into southern Maine as winters get warmer.

The tea kettle birdhouse is a bit of a visual joke. The startling loud, clear song of the Carolina wren is sometimes written as “tea-kettle, tea-kettle, tea-kettle.” The small bird with the big voice sings this three-syllable chord, or others with the same cadence and tone, over and over again. They sing each set of chords in bursts of three-to-five repetitions, sometimes adding a final “tea” to close the chorus.

Early this summer, the male in our backyard would awaken me every morning at sunrise with those phrases repeated dozens of times. He was claiming this as his territory, and each note was clear and sharp and true. It’s hard to imagine a more pleasing alarm clock.

By mid-August, Carolina wrens have already established their well-defended territories. The song of the bird I saw on our friend’s patio chair wasn’t defining turf, but that short musical burst was attention-getting nevertheless.

After that one brief display of his glorious voice, the Carolina wren retired to the hedgerow for the night.

It was not the full symphony that I knew was there, but somehow that unfinished bit seemed just right for that August night. Sometimes a single, clear phrase is enough to savor.