A cloud of midges swarmed in the shaft of sunlight that found its way through the leafy canopy. We stood still, a light sheen of perspiration glistened on our arms and the smell of the fecund earth drifted up from the forest floor.

We were surrounded by bird sounds. Nearby, a thrush rustled through the duff in search of grubs and worms. Farther away, a woodpecker interrupted its drilling to issue its raucous call.

Our attention was on a sweetly whistled warble coming from a bird just yards away. Its song abruptly ended and it flitted to a nearby branch. The bird was now in the shade. It took just a moment for our eyes to adjust to the relative darkness. As they did, the bird’s bright yellow rump and a golden streak on its side tucked up against its wing, came plainly into view.

The yellow-rumped warbler (Dendroica coronata) is one of the most common members of the large wood warbler family (Parulidae), which includes about 50 species in North America.

Wood warblers are the darling of many birders. They are found only in the Western Hemisphere.

These annual migrants come to North America to sing and nest and breed.

They are noted for their diminutive size and an amazing array of bright breeding-season color patterns featuring yellow, green, olive, red, blue and even orange. Their songs are as varied as their colors.

Most wood warblers are neotropical migrants. That is, they winter in the tropics of Central and South America before flying north to breed.

Like other members of the wood warbler family, yellow-rumps eat insects during the spring and summer. They winter as far south as Panama, but don’t qualify as true neotropicals. Most yellow-rumps winter in the southern United States and Mexico.

They are unique among warblers in that they are able to digest the wax of bayberries and myrtle bushes, which allows the birds to eat when it is too cold for insects. The yellow-rump is the only wood warbler regularly seen in the United States in winter.

The bird that we were tracking closely with our binoculars was busy snatching insects.

Most of the yellow-rumps passing through the Chesapeake region are on their way to breeding grounds in the boreal forests of Canada. Some will nest here, though, in the far reaches of the Bay’s headwaters. The mountain forests of West Virginia and the relatively cooler temperatures of upstate New York provide suitable habitat for yellow-rumps to nest.

In June, yellow-rump females make a cup nest in a conifer tree, where they will incubate three to six eggs.

The male brings insects to its mate while she is brooding. Chicks are born without feathers and are totally helpless. After 10 days they are ready to fly, but they require additional feeding help from both parents for several weeks.

These warblers have a few common color patterns, but they are a “polytypic” species, a term ornithologists use to denote a single species that has several color patterns.

Although there are a number of intermediate forms, most yellow-rump warblers can be divided into two subpopulations: the myrtle yellow-rump found in the eastern United States and the Audubon form of the West. In both forms, the bird measures about 5.5 inches in length with a 9-inch wingspan. Yellow-rumps weigh less than half an ounce.

As its name suggests, this bird is most often identified by the bright yellow patch on its rear. Matching yellow streaks can be seen on the sides. Both forms have a white vent and bold white wing bars.

We could plainly see the white throat patch that is characteristic of the myrtle form (the Audubon’s is yellow). Its short black beak gave way to a white eyebrow. Barely visible was a yellow cap, indicating that this was a male. Underneath, the bird was all white except for a streaked black chest band. White wing bars stood out against a black-and-charcoal body. The long tail was black, showing plenty of white on the outer feathers.

The female is duller overall, lacks the yellow cap and has tan undertones on its body and head.

The yellow-rump we were watching finally flew out of view, deeper into the dark forest. We took it as a signal to head back to the parking lot.

I took a last look at the stark patterns of light and dark cast by the mosaic of sunlight and shade. We had not traveled far into the forest, nor had we stayed for long. I was emerging from the shadows of a two-year bout with an illness that had taken a serious toll on my mobility and left me with limited energy.

Today’s short walk held the promise of a new birding season in the field. The thought renewed and strengthened me. After all, even in the shadows of life, beauty sometimes abounds.