The Marsh Wren photograph above is from the Lake County Forest Preserves' Species Database. These secretive but brave and territorial birds are endangered in Indiana. They require emergent marsh habitat; at the Lake Station Mitigation Bank, Hybrid Cattail (Typha x glauca) has become abundant in places, and Marsh Wrens have certainly benefited. Below is a video from the Lake Station Mitigation Bank in which you can hear the bubbly songs of several Marsh Wrens (in addition to the conk-la-ree songs of Red-winged Blackbirds, Agelaius phoenicius). The song of the Marsh Wren is described as sounding like a gurgling warble followed by a dry, rattling trill. Unfortunately, the songs in my video don't sound exactly like they did when I was in the field, but this video at least gives an idea of how much they were singing at this site.
Although cattail is generally considered undesirable at mitigation wetlands, it seems there has been a positive correlation between increasing cattail populations and an increasing Marsh Wren population at this site. This introduces the management question of which is more important - a state-listed bird species or a diverse plant community. Prior to development and habitat fragmentation, this likely was not an issue, but now, it seems increasingly likely that we are going to have to make this difficult decision.