The term 'Marshland Bird' can be broken down into two crossword solutions: BITTERN (7 letters) and HERON (5 letters). Bitterns are a type of wading bird that are found in wetlands, marshes, and other shallow water habitats. They are known for their loud booming call which is often heard during the breeding season. Herons are also a type of wading bird that inhabit wetlands, marshes, and other shallow water habitats. They are characterized by their long legs and long necks, and they feed on fish, frogs, and other aquatic animals. Both bitterns and herons are common birds in marshland habitats.