The sedge wren (Cistothorus platensis) is a small songbird of the wren family. It was formerly known as the short-billed marsh wren, and in South America is often known as the grass wren. There are about 20 different subspecies which are found across most of the Americas. Some of these forms may be separate species that could be split in the future. North American populations migrate to coastal areas in the Southeastern United States, and the entire Gulf Coast south through eastern Mexico. This bird's numbers are declining, possibly due to habitat loss.