The marsh harriers are birds of prey of the harrier subfamily. They are medium-sized raptors and the largest and broadest-winged harriers. Most of them are associated with marshland and dense reedbeds. They are found almost worldwide, excluding only the Americas. At the beginning of the 20th century, the marsh harrier was hunted to extinction in the United Kingdom. After being reintroduced from other regions, its population steadily increased until DDT threatened it, along with other raptors, in the 1950s and 1960s. Since, the population has slowly and steadily increased.