NATURE NOTES: The goldfinch’s winter clothes

By LESLIE BISHOP, guest columnist

The beauty of winter is subtle.

The brilliant hues of fall have transitioned into rich browns and grays. Some birds seem to mimic the transformation of the landscape.

I am watching our backyard feeder, and goldfinches are dining on sunflower seeds. It wasn’t too long ago that these same birds flashed their brilliant yellow as they perched precariously on coneflower seed heads. Now, they reflect the muted shades of the winter landscape.

American Goldfinches are year-round residents of Brown County, and visit feeders in large groups in all seasons.

In the summer during the breeding season, the male goldfinches are a brilliant yellow with black wings and a black cap. After nesting in August, the goldfinches begin to molt into a new paler plumage. Between September and November, they replace all of their feathers. By December, the males look so different from their summer plumage that some people mistake them for a different species.

American Goldfinches are unique among finches because they molt twice a year. In late winter, goldfinches begin to replace their body feathers in a partial molt. The wing and tail feathers remain from the previous fall. By March, the males once again have vibrant yellow bodies ready for breeding season.

It is not just the males that molt twice a year; females also replace their feathers, but retain the same muted colors throughout the year. Buntings, tanagers and warblers share this same pattern with goldfinches of two molts per year, and sport a flashy plumage only during breeding season.

All birds molt. Feathers, like our hair and nails, are nonliving structures composed of the protein keratin. When they become worn or damaged, they drop off and are replaced. New feathers develop from feather follicles, which are invaginations in the skin lined with specialized cells. Feathers must be replaced gradually in order for the bird to continue foraging and flying. Birds can look bizarre during molts, with patchy color patterns and ruffled feathers.

Feathers are critical to bird survival: They provide insulation, water repellency, and protection from the harmful rays from the sun, and they make flight possible. In addition, as with our goldfinches, a change in feather color can aid in blending into the landscape in winter or in attracting mates in spring.

The process of molting requires a lot of energy; thus, most songbirds molt only after their breeding season. With a new coat of feathers in the fall, the birds are ready for harsh winter conditions.

Some field guides call the winter plumage of the goldfinches dull, but I call it subtle. And like the winter landscape, these quiet, muted colors are beautiful.

Stripped of their leaves, the large trees in our woodlands now expose their dramatic silhouettes. The young beech trees that cling to copper leaves add splashes of color, and the bone white tops of sycamore trees flash in the sunlight. In our meadow, the tall grasses are now in lovely shades of russet and tan.

And the goldfinches with shades of pale yellow, olive green and gray, are in harmony with the subtle beauty of winter.