Cistothorus palustris is a bird species commonly known as the marsh wren. Synonyms for this bird include the catbird, the swamp wren, and the reed bird. Marsh wrens are small and secretive with distinctive white eyebrows and a long tail that is often held erect. They are commonly found in wetland habitats, such as marshes and swamps, where they build their nests in dense vegetation near the ground. Their song is a complex series of chirps, trills, and gurgles. These tiny birds are important members of their ecosystems, serving as seed dispersers and predators of insects and other small invertebrates.