The term MARSH DENIZEN can be solved by the crossword solutions RAIL, TOAD, MUSKRAT, EGRET, HERON, and CRANE. These animals are all commonly found in marshy areas, and each has its own unique characteristics. The RAIL is a small, secretive bird that prefers to stay hidden in dense vegetation. The TOAD is a amphibian that is often found near water sources. The muskrat is a semi-aquatic rodent that builds lodges out of vegetation. The EGRET is a large white bird that is often seen wading in shallow waters. The HERON is a long-legged wading bird that hunts for fish in shallow waters. Finally, the CRANE is a large bird that is often seen standing in shallow waters. All of these animals are common inhabitants of marshy areas.