The Northern harrier is a slender, medium-sized hawk characterized by a noticeably long tail, bold white rump patch, and owl-like face. Commonly encountered in large expanses of open country, its main hunting technique is through use of a distinctive buoyant, gliding flight low over the ground that relies heavily on visual as well as auditory cues to detect prey.
The larger females have rich brown upperparts while adult males are mostly light to medium gray, sometimes appearing almost ghostly silvery-white. Males are noted for their high-spirited and acrobatic courtship displays, in particular a series of dives and barrel rolls in multiple loops that serve as a means of advertising territory occupancy.
The Northern harrier is common during summer and migration in open habitats east of the Cascades, with numbers decreasing in most areas during winter. An exception is in the lowlands of Umatilla and Morrow counties, where the harrier is common in winter due to an influx of wintering birds. The harrier also remains common year-round in the Klamath Basin and is the second most commonly encountered wintering raptor at Malheur National Wildlife Refuge.