Nature Bulletin No. 302-A   April 13, 1968
Forest Preserve District of Cook County
Richard B. Ogilvie, President
Roland F. Eisenbeis, Supt. of Conservation

****:HOUSE WRENS

Ten years ago this spring we moved and, of course, put up some nest 
boxes for wrens and bluebirds. The two wren houses had entrance holes 
just a little smaller than a 5-cent piece, so that sparrows could not get 
in, but we made the mistake of putting one of them in a very shady 
place. It was never used. The other, a fancy four-apartment affair, we 
hung on a hawthorn tree near our picnic table, fireplace and lawn 
chairs. A male wren took possession and put a lot of twigs in all four 
compartments but when Jenny arrived, several days later, she threw out 
all of "his stuff" in the south one and built a new nest of smaller twigs 
and soft strips of bark, lined with some grass and feathers. We have 
watched them and their descendants raise two broods every spring and 
summer. They are part of our family.

The scientific name for the wren means "cave dweller" and, with the 
exception of the marsh wrens, they do nest in some cozy nook or cavity. 
There was a time when House Wrens lived in forests in tree cavities 
such as those made by the woodpeckers but now, like the robin, most of 
these fussy saucy little elves have adopted man as their companion. We 
are fortunate. Wrens are among the most prolific of all our songbirds, 
and about 98 percent of their food is injurious insects: grass hoppers, 
crickets, beetles, bugs, caterpillars and weevils. There is a record of a 
pair making 1217 trips to feed their young, on just one June day!

House wrens are distributed over most of the United States and 
southern Canada. There are three varieties, all found in Illinois but, 
being dull brown above and dull gray below, without any distinctive 
markings, only an expert can tell which is which. They are about 5 
inches long from the tip of the long slender curved bill to the end of the 
rounded tail, which is usually perked up over the back. They are very 
energetic, nervous and scrappy; do a lot of scolding -- a grating chatter; 
and the male frequently destroys the eggs of other birds that attempt to 
nest within what he considers his territory. His song is a series of high-
pitched notes that bubble out in a rapid burst and then die away.

Twice each year, Jenny Wren lays from 6 to 10 little brown-specked 
eggs in a nest that may be in a bird-box, tin can, or clay flowerpot -- if 
these are not placed too high; in the hollow limb of a fruit tree or a hole 
beneath the eaves of a house; or in such queer places as an old straw 
hat, a glove, the pocket of a garment hanging on a back porch, or a 
hollow part of a piece of idle machinery.

Sometimes, in Illinois, the house wren is driven away by a Bewick's 
Wren, of which there are several varieties. The two are very much alike 
in temperament, habits and appearance, but Bewick's wren is slightly 
larger and has a longer tail which it flirts from side to side. It has a 
white stripe over the eye and a white spot at each corner of its tail, 
although these markings are difficult to see. Its song is much different: 
high and variable but clear and melodious, like that of the song 
sparrow.

In many parts of the United States, east of the Great Plains and 
especially in the more southern states, we also have the Carolina Wren. 
Although it usually prefers woodland thickets, brush piles and stream-
bank tangles, it sometimes becomes common around dwellings and 
nests in boxes. It is larger and chunkier than the other two wrens, buffy 
below and much redder above, with a conspicuous white stripe over the 
eye. This wren sings its clear chanting whistle all day, in all weather, 
nearly the whole year round.