Marsh Wrens, as their name implies, usually hang out in damp, marshy places, gobbling up insects, spiders, and small snails as they maneuver through the cattails and reeds. However, I found a male Marsh Wren singing loudly from the tops of Big Bluestem grasses on a hill-top prairie, and admired his ability to cling to the floppy grass stems while broadcasting his song of loud, shrill twangy notes.
Marsh Wrens are not melodious singers like the House Wren and Winter Wren. Their song sounds to me more like the string of a bass guitar vibrating.
Marsh Wrens males are flirty guys, and may attract a number of females as mates. Each female builds her own nest, incubates her eggs, and feeds her chicks. The male secures the territory for these multiple households, and builds several dummy nests, which he might use for roosting, but probably are also useful to confuse nest predators.
These birds are somewhat secretive and difficult to see in their typical aquatic environment, but the males do climb to the tops of the tallest plants to proclaim their territory, and often end up straddling two stems in a very acrobatic fashion.