Northern harrier: the "Marsh hawk"

By Kathy Urffer

The Northern harrier (Circus cyaneus) is a native, permanent resident of our area. This medium-sized raptor, formerly referred to as the "marsh hawk," has been listed as endangered in New Jersey since 1984, and is listed as threatened in New York. We should count ourselves lucky that it nests in various areas of the Meadowlands, including, at various times, Teterboro Airport, the marshes of Bellmans creek, and on the Empire tract, the controversial sight that had been slated for development by the Mills Corporation (see Tidelines: Winter 2002, Fall 2002).

The Northern harrier hunts on the wing and uses its hearing to locate prey. It is a beautiful and efficient flyer and can cover up to 100 miles a day seeking small rodents and birds to eat. During courtship, the male performs an intricate aerial dance. Harriers generally have about 4-5 young in a clutch and parental care is offered by both parents. The young stay dependent on the parents for about a month before they are fledged and off on their own. Because the stick and grass nest is built on the ground (unusual for hawks), open prairie and wetland habitats are important to the preservation of this species.

Harriers were abundant in this region until the beginning of the 20th century when their numbers began to dwindle. More recently, declining numbers during Christmas bird counts from the 1950s to the 1970s coincided with extensive dredging and filling of coastal wetlands in New Jersey during the same period. Additionally, the use of DDT in the 1950s and 1960s caused reproductive failure due to brittle shells that broke easily. The use of this chemical had a similar effect on many of our raptor species. DDT was banned in 1972 but residues in the form of DDE may still plague the species.

Current threats to the Northern harrier include ongoing pesticide use and the loss of breeding habitat, specifically the filling of wetlands and the development of grasslands habitats.