Deer in Spring Landscape

Maryland's Wild Acres

Creating a Wild Backyard - Wrens of Maryland

A cheerful song, a long tail that is often held straight up, and a slightly downward curving beak make the wren unmistakable among our songbirds.

Wrens are in the bird family known as "Troglodytes", which is Latin for "Creeper into holes" and "cave dweller". This is an apt name for a bird that nests in almost any small cavity. Besides bird houses and old woodpecker holes, these birds have been known to nest in spools of string, fishing creel hung in sheds, boots and shoes, pockets of clothing, hats and flower pots just to name a few!

Natural History

Wrens begin nesting from March through August and can raise two broods in one season. Male wrens build many nests, sometimes as many as five or six, for their intended mates. Biologists think this may be the male wren's strategy for keeping other birds from nesting in his territory. This is sometimes a problem along bluebird nest box trails, where the numerous wren nests discourage bluebirds from nesting. It is not legal to remove wren nests from bluebird boxes. Wrens are protected by the Migratory Bird Treaty Act. Under this federal legislation, they may not be taken or harassed, and their nests may not be destroyed. Wrens lay four to nine eggs which hatch in about two and a half weeks. The young leave the nest about two weeks later.

Kinds of Wrens

Six species of wren can be found in Maryland. This list includes everything from the common Carolina and House Wrens to the rare Bewick’s Wren.

House Wrens are Maryland's most common wren species and are the one most likely to nest in a backyard nest box. These wrens like to live in deciduous woods and wood edges, backyards, parks and gardens. House Wrens mostly migrate south in the winter, but sometimes may hang around after the first frost if suet is offered in feeders. It is rare for House Wrens to stay in Maryland through Christmas.

Male wrens arrive back in Maryland before females so that they can begin building a choice of nests for the female. Young males tend to build nests closer to established nests, while older males prefer to make their nests further away from others. When the females arrive, they choose a nest and lay their eggs. If nesting in a box, nest box temperatures are crucial for House Wrens. House Wren eggs cannot withstand temperatures over 106 degrees Fahrenheit or under 65 degrees Fahrenheit. House Wrens, like all wrens, are primarily insect eaters and favor the gypsy moth, which is an invasive insect that can wreak havoc on trees.

House wren checking out a tree cavity by USFWS

Carolina Wrens are year-round residents in Maryland. This is the largest wren in the eastern United States. Carolina Wrens are a reddish brown in color and possess a distinctive white streak over the eye and a buff colored underside. Sometimes called the mocking wren, Carolina Wrens often mimic the sounds of other birds but are best known for their "teakettle, teakettle, teakettle" and "cheery-cheery" songs.

Carolina Wrens may pair bond at any time of the year, and these bonds last for life. Members of a pair stay and forage and move around their territory together. Carolina Wrens will frequent suet feeders in the winter and may even seek shelter out of nest boxes lined with grass. Carolina Wrens will nest in a variety of locations including hanging fern baskets and flower pots. Brush piles are also a great way to attract Carolina Wrens to your yard. For information on how to construct a brush pile in your yard, check out the Wild Acres brush pile page.

Carolina Wren, photo by Greg Miller

Marsh and Sedge Wrens migrate through most of Maryland but are found year-round in marshes on the lower Eastern Shore. Marsh Wrens prefer cattail marshes, or bulrushes and reeds of tidal creeks, coastal salt and brackish marshes as well as inland river valleys. Because of this, most breeding populations of Marsh Wrens are located on the coastal plain of Maryland. Sedge Wrens prefer shallow sedge and freshwater wetlands where grasses and sedges grow with scattered shrubs.

This species is a Highly Rare breeder in Maryland, with a few breeding locations in Garrett, Allegany, Charles and Queen Anne’s Counties. Both wrens build nests that are well hidden, and sometimes nest in colonies with other wrens. Marsh Wren females build their nests mostly by themselves, but the males still follow wren tradition and build a series of dummy nests before and after the females arrive. These two wrens are unlikely to nest in boxes.

Marsh Wren with a tasty catch by its nest, photo by George Gentry, USFWS

Winter Wrens spend their summer in cool forests and swamps in the Northeast U.S., including our own Garrett County. Winter Wrens can be found in Maryland year-round, and many Winter Wrens spend their winters on the lower Eastern Shore. These wrens are found near brush piles and the edges of swamps. Like other wrens, they primarily feed on forest insects, including bark beetles, weevils, borers, and the moths of spruce budworms.

Winter Wrens are not typical feeder birds, however, they are attracted to fallen, dead trees. So, if you live in western Maryland and can leave some snags on your property, then you might be able to attract these energetic birds. For more information on Snags, check out this Wild Acres article.

Winter Wren, photo by USFWS

Bewick's Wrens were so named by Audubon for his friend Thomas Bewick, an English artist and wood engraver. The decline of the Bewick's Wren in Appalachia has been a major concern of the Maryland Natural Heritage Program, which monitors the status of rare plant and animal species in the State. Since 1986 the Bewick's Wren has been classified as endangered under regulations of the Maryland Endangered Species Act of 1971. This classification provides important status for the species, protecting the wren from many human-caused forms of disturbances. Unfortunately, with no breeding Bewick's Wrens known to be left in the State, this protection may have come too late.

Bewick’s Wren, photo by Dave Menke, USFWS

How to Build a Wren Nest Box

Materials

  • 1" X 6" X 4' lumber

  • 1 1/2" galvanized nails

  • Construction

    1. Mark and cut pieces out of lumber

    2. Cut entrance hole 1 1/8" in diameter, one inch from the top of the front piece.

    3. Drill 1/4" holes in the bottom piece for drainage.

    4. Drill 1/4" holes near the tops of the side pieces for ventilation.

    5. Assemble

    Wren Nest Box Illustration for Cutting & Assembly

    Wren Nest Box Tips

  • Do not put a perch under the opening in the front piece. Wrens will not need a perch to get into their nest box. However, European Starlings will sometimes use perches to rest on while trying to increase the size of an opening into a nest box.

  • The size of the entrance hole will allow only wrens and similar sized or smaller birds like chickadees and nuthatches inside. Larger birds, like House Sparrows or starlings will not fit through the hole. The entrance hole can be cut wider than it is tall - about 1/4" tall and 2 1/2" wide, so that the wrens can more easily fit through with the sticks and other material for their nest.

  • Clean out the nest box after the young have left so that another brood can be raised. Wrens will tend not to use the same nesting material twice and so will make a second nest elsewhere if you do not clean it out.

  • Place the nest box 5-10 feet above the ground, under the eaves of a building or a tree limb. Wren boxes can be firmly fixed to the side of a building or tree or can be hung freely from a wire.

  • Be sure to disinfect nest boxes each winter using either boiling water or a weak bleach solution.

  • To help attract wrens, offer suet, peanut butter or meal worms in feeders.

  • Of the wren species that live in Maryland, only House and Carolina Wrens will nest in boxes.
     

  • Invite Wildlife to Your Backyard!

    For Additional Information, Contact:

    Kerry Wixted
    Wildlife and Heritage Service
    580 Taylor Ave, E-1
    Annapolis, MD 21401
    kerry.wixted@maryland.gov
    Phone: 410-260-8566
    Fax: 410-260-8596

    Acknowledgements:

    House Wren , photo by USFWS
    Carolina Wren, photo by Greg Miller
    Marsh Wren, photo by George Gentry, USFWS
    Winter Wren, photo by USFWS
    Bewick’s Wren, photo by Dave Menke, USFWS
     

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    Kerry Wixted
    Natural Resources Biologist II
    Maryland Wildlife and Heritage Service
    MD Dept of Natural Resources
    580 Taylor Ave., E-1
    Annapolis MD  21401

    phone: 410-260-8566
    fax: 410-260-8596
    e-mail: kerry.wixted@maryland.gov

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