It was not the Red-tail they were after. And in its talons it held a lifeless magpie. Northern Harriers hunt on the wing during the day cruising low over open fields or marshlands with their wings held in a V-like pattern. The birds systematically search an area by flying 5 to 30 feet above the vegetation. When prey is located, the Harrier either stalls in flight and pounces, or hovers like a helicopter for a better look, or a better listen.
Harriers have an owl-like face.
The concave facial disk and relatively large off-set ears enable the bird to use triangulation of sound to help locate prey such as mice, voles, juvenile rabbits, frogs, pheasant chick, and other birds in dense vegetation. Now, I would add Black-billed Magpie to their prey menu, although magpies may represent a minute fraction of the Harrier's diet. Females construct most of the nest in tall weeds or reeds often on top of a low bush or knoll on dry ground. In the Moab sloughs, Harriers are winter residents but may be observed in summer. They are not known to nest in the sloughs.