The sedge wren (Cistothorus stellaris) is a small and secretive passerine bird in the family Troglodytidae.

It is often found in wet grasslands and meadows where it nests in the tall grasses and sedges and feeds on insects.

The sedge wren was described by the German ornithologist Johann Friedrich Naumann in 1823 under the binomial name Troglodytes stellaris.

[7] During the breeding season they are found in the southern half of Alberta and Saskatchewan and in southern Ontario and Quebec in Canada and in the United States, west of the Appalachians, from the Canadian border to Missouri and northern Arkansas.

[7] During the breeding season, sedge wrens generally occupy meadows and wet grasslands.

[10][15][16] During winter, migratory sedge wrens can be found in a variety of habitat as long as there are sufficient insects to eat.

[7] Males sing from late winter to early spring on non-breeding grounds and throughout the breeding season to attract mates.

It is hypothesized that they do so to send the maximum amount of stimuli to the listener whether it be a male or a potential mate.

This large variation results from the tendency of North American sedge wrens to move often.

Therefore, there is no selection for a precise imitation of the neighboring birds and variations arise in the males' songs.

Moreover, because their songs vary so much naturally, it decreases the overall variation over large geographic scales and wrens from all over North America can communicate with each other regardless of which population they came from.

They will typically leave their breeding grounds when frost reduces significantly the abundance of insects.

[15] They depart anywhere from August in the northern part of their range to the end of October in the central states to arrive in their wintering grounds starting in early September.

One hypothesis is that these birds are coming from the northern part of their range where shorter summers prevents them from having a second brood in the same location.

Another similar hypothesis is that these birds come from various locations where the environmental conditions changed and were no longer suitable for raising a second brood.

A final hypothesis is that males that were not able to breed at their previous location relocate to the central plains.