The Northern Harrier nests on the ground in a slightly elevated area or in thick vegetation. In all forms there is a white rump patch. The male is a pale gray. The female is brown on the back with a buffy breast that has streaks on from the breast to the belly. Male and female juveniles look very much like the adult female northern harrier but the juveniles have a very pumpkin colored breast and belly and few or no streaks.
Northern harriers have a facial disk similar to that of an owl.
Older field guides may call it the marsh hawk. Northern harriers hunt by flying low in seemingly random patterns across a field or marsh. Northern Harriers can be seen at Hawk Hill in the Marin Headlands during the fall raptor migration. Harriers hunt by sound more than other raptors. The facial disk directs the sound of prey to their ears in much the same way that an owl's facial disk does.