Wren species occupy various habitats
I miss the song of the house wren. The chirping, bubbly and incessant song - nearly as persistent a singer as the red-eyed vireo - is a birdsong that I came to enjoy when I lived just a few miles north of where I do now. What's interesting is that the surrounding habitat is not all that different between my former and current homes. Yet, for whatever reason, and despite putting up wren houses, no house wrens have moved in, much less even stopped by for a look-see.
Some would argue that it's all well and good; that being house "wrenless" is a blessing in disguise. The house wren, though a tiny tot, is a somewhat aggressive bird that has been known to displace other species of cavity nesters by stuffing birdhouses full of sticks. Indeed, ask anyone knowledgeable about the needs of bluebirds, they will tell you not to erect bluebird nest boxes adjacent to house wren habitat.
Minnesota is home to four species of wrens. Rather secretive in behavior, wrens prefer instead to scuttle about within their respective environments searching for insects and fruit. With narrow heads and long, slender bills, wrens are constantly probing cracks in woody and herbaceous vegetation in their continuous hunt for food. Wrens, bundles of energy, are always on the go.
As I already mentioned, the house wren is just one of four species of wrens. The other three - winter wrens, sedge wrens and marsh wrens - occupy different habitats, but are all quite similar in physical appearance. And of this foursome, the smallest and darkest of the lot, the winter wren, is probably the wren least seen or heard.
Most wrens nest in cavities, and as one particular wren's name implies, the house wren is one such wren. Many a bluebird house placed on a post near a woodlot or orchard doesn't escape the notice of a courting male house wren. In fact, various other objects become nest sites as well. Old shoes or boots, gourds, open containers, and even hornet nests have all served as this wren's "house."
Male house wrens arrive in the springtime ahead of the females in order to establish their breeding territories. A tireless singer, the male house wren sings its combination of trills and rattles with exuberance and conviction. There's no mistaking the boundaries of a house wren's domain, for he flies from perch to perch singing earnestly throughout the day, into the evening and sometimes occasionally during the night during the breeding season.
Between songs while busily defending his territory, the male house wren also remains busy by building nests. Some people become astonished by this behavior when they discover their bluebird houses stuffed full of sticks. But, that's the way of the house wren. You see, all of that nest construction is done to impress his ladybird friend. And if he's lucky, she will choose one of his numerous false-nests and raise his offspring.
Another two species of Minnesota wrens are the sedge wren and marsh wren. Just as untiring songsters as their upland cousin the house wren, both sedge and marsh wrens sing frequently, loudly and vigorously.
Sedge wrens are typically found in grass and sedge meadows that are often ringed with short shrubs. A secretive bird, these wrens are normally not seen unless flushed or observed singing heartily from the end of a stem or blade of grass. His song is described as "sharp staccato chips" culminating in a rapid series of "chaps and chats." It's distinctive enough that with only a few encounters and confirmed observations, one can readily identify future meetings by hearing alone.
As with the house wren, several false or "dummy" nests are built throughout an individual male bird's territory. But unlike the house wren, tiny woven balls of grass with a single opening on its side are constructed about a foot or two above the ground. In the sedge wren's case, the cavity is built, not found.
Marsh wrens occupy wetlands as well, though different types of wetlands than what sedge wrens prefer. Aptly named, marsh wrens are found in wetlands dominated by cattails and reeds. The largest wren of the four species found in Minnesota - though not that large, only five inches in length - marsh wrens are usually heard before visually observed.
The male sings from the confines of tall marsh vegetation, gripping tightly the round stalks of reeds or the green blades of cattails, while spewing a very musical and gurgling series of rattles and trills. So boisterous is the singing male during the breeding season that he rarely stops singing, even at night.
Winter wrens are not as common in Minnesota. The smallest wren of the nine occurring in North America, the winter wren is actually the only wren of the 59 worldwide species that can be found in both the New and Old Worlds. The four-inch dark brown bird with the very short and cocked tail prefers summertime haunts of cool coniferous forests where it nests and hunts for insects.
Indeed, wrens are remarkable little birds. Similar to one another in appearance and song, yet occupying differing habitats ranging from upland to lowland, wrens are worth our while as we get out and enjoy the great outdoors.
Blane Klemek is the Bemidji area assistant wildlife manager, DNR Division of Fish & Wildlife. He can be reached at firstname.lastname@example.org