A diminutive dynamo of a bird has slowly been moving into our state. It is shy and reclusive, and more likely to be heard than seen; nevertheless, it is making its presence known in Maine.

The bird in question has understated, but beautiful, plumage: rusty upper parts and warm cinnamon under parts contrast with a white chin and a bold white “eyebrow” stripe. It holds its tail up at an angle from its body, as others of its brethren do; and its whimsical song, “tea-kettle, tea-kettle, tea-kettle,” rings out boldly from shrub and hedge. It is the Carolina wren.

Traditionally the bird inhabited more southerly areas of the United States, from Massachusetts to Florida, and out to the Midwest, down into Mexico and parts of Central America. But by all accounts the bird has been moving steadily northward since the early 20th century.

The wrens have shown up in backyards, attracted to the suet put out by bird feeders, and have been reported on Maine Audubon’s Rare Bird Alert. The other day, I got an e-mail from Judy Markowsky, Fields Pond Nature Center director. She said she had received a call about a Carolina wren seen in Millinocket.

“This is one of a handful trying to survive the winter in Maine,” she said, adding that they are expanding their range north.

“This works in a mild winter, but survival is less likely in a severe one,” she said.

Whether this winter is severe enough to kill off those wrens still remains to be seen. I did wonder how a bird could be at home in Maine as well as Mexico; even in a “mild” winter, our state’s climate would differ drastically from Mexico’s! The answer lies in the bird’s habitat and food requirements.

The Carolina wren is a generalist; it does not need a specific habitat in which to reproduce, nor does it feed on only one type of food. It also uses different foraging techniques; although it usually feeds on the ground, it can also climb tree trunks and branches, gleaning dormant insects from beneath the bark – much as our resident nuthatches and brown creepers do.

It will eat seeds and fruits as well as insects, and it is quick to take advantage of the suet cakes put out by people; this rich source of fat and protein could be life saving in our climate.

It is at home in the woods or around the woodshed. In fact, it will not hesitate to construct its nest in any human artifact: mailboxes, glove boxes of abandoned vehicles, tin cans, coat pockets, flowering pots, and shoes, as well as any other suitable cavity, including human-made nest boxes.

If you see a Carolina wren in your yard and would like to give it a helping hand, try these two things: put out suet and provide a roosting box for shelter. Roosting boxes differ from nest boxes in that they are built to house several birds; the entrance hole is also placed at the bottom, so as to reduce drafts. A nest box with a clean bed of straw on the bottom will do in a pinch, though.

If you do see Carolina wrens, or any other uncommon bird, please report your sighting by e-mailing the Fields Pond Nature Center at fieldspond@juno.com.

Chris Corio, a volunteer at Fields Pond Nature Center in Holden, can be reached at fieldspond@juno.com