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.
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.
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.
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.
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.
How to Build a Wren Nest Box
Materials
- 1" X 6" X 4' lumber
- 1 1/2" galvanized nails
Construction
- Mark and cut pieces out of lumber
- Cut entrance hole 1 1/8" in diameter, one inch from the top of
the front piece.
- Drill 1/4" holes in the bottom piece for drainage.
- Drill 1/4" holes near the tops of the side pieces for
ventilation.
- 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