Species Profile
The sedge wren has a rather unusual lifestyle that is well suited to the transitory nature of its habitat. Sedge wrens tend to be nomadic, moving from place to place even within the breeding season and rarely occupying locations in consecutive years. Males also may have more than one mate. There is a strong suspicion that sedge wrens will nest multiple times in different locations during the extended breeding season. These habits make this little bird difficult to study and understand. In summer, sedge wrens are found from southern Saskatchewan and Minnesota across the Great Lake states to the east. They winter along the Atlantic and Gulf coasts, as far south as Mexico. Sedge wrens arrive in Pennsylvania in April and May, and migrate south to brackish coastal marshes from August to October. Sometimes they arrive on breeding grounds in mid- to late-summer apparently after nesting elsewhere. Among the last birds to nest in the state, sedge wrens may be found nesting here as late as August. They nest in wetland areas or wet meadows and hayfields. A typical clutch of six or seven white eggs is laid in a globular nest built up to two feet off the ground. Young hatch in 12 to 14 days, and leave the nest at two weeks of age. Two broods can be produced each year.
For nesting, sedge wrens require damp meadows or marshes where sedges and grasses are interspersed with small shrubs. They apparently don't do well in cattail marshes. Rainfall patterns can have an important effect on its distribution in any year.
Sedge wrens (Cistothorus platensis) may appear and possibly breed in Pennsylvania almost any time from late spring to early fall. They are absent from much of their historic range in the state, even where there is suitable habitat. Sedge wrens are rare, irregular migrants and breeders, not known to occur at any particular location in Pennsylvania on a regular basis. Despite the species' reputation as an ephemeral breeding bird and its slipping population across the northeastern United States, evidence of breeding in Pennsylvania increased slightly between the first (1982-1989) and second (2004-2008) Breeding Bird Atlas projects. During both Atlas periods, the sedge wren was located most frequently in marshes and wet meadows in Erie, Crawford, and Lawrence counties. Absence from much of its historic range in Pennsylvania and the larger regional decline may be attributable to habitat loss, but could also be related to the difficulty in seeing them in their preferred habitat, dense grass. Sedge wren was designated threatened in 1985's Species of Special Concern in Pennsylvania, published by the Pennsylvania Biological Survey. In 2005, the Pennsylvania Game Commission changed its status to endangered from threatened on the advice of the Ornithological Technical Committee of the Pennsylvania Biological Survey.
Sedge wrens are rare throughout their range. They used to be found nesting in scattered locations across Pennsylvania. Over the past several decades, however, they have disappeared from many of their former haunts, and numbers have dropped significantly in others. The loss of habitat and changing agricultural practices are thought to be responsible for this decline.
The specific locations where sedge wrens currently nest in the state need to be determined and then, where feasible, protected. In general, wet-lands deserve more proactive protection on private lands, including acquisition or voluntary techniques to protect habitat. Certain grassland and wetland management techniques may be favorable to this species. The planting of warm season grasses, preventing encroachment of woody vegetation into idle grasslands, and delaying mowing of hay are among those practices that would benefit this species. A few locations where it has nested are designated as Important Bird Areas in our state.
Sedge Wren