The Northern Harrier is a medium-sized raptor that breeds on wetlands, bogs, prairies, farmland, marshes, grasslands, swamps and other open areas. The raptor frequents the San Dieguito River Park corridor from the coastal areas up into the foothills.  

 

Northern Harriers are one of the few raptorial birds known to practice polygyny. That's where one male mates with several females. Up to five females have been known to mate with one male in a season. Northern Harriers are sexually dimorphic, meaning the males look different than the females. The males are gray in color with a distinctive white band above the tail while the females show varying shades of brown with the same distinctive white band. Northern Harriers build their nests on the ground or on a mound of dirt or vegetation. Nests are made of sticks and are lined inside with grass and leaves.

A typical harrier hunts on long wings held in a shallow V in its low flight during which the bird closely hugs the contours of the land below it. Most harriers hunt primarily small mammals. Preferred prey species include voles, rats and ground squirrels. Up to 95 percent of the harrier's diet comprises small mammals.

Harriers hunt by surprising prey while flying low to the ground in open areas, as they drift low over fields and moors. The harriers circle an area several times listening and looking for prey. Harriers use hearing regularly to find prey, as they have exceptionally good hearing for diurnal raptors, this being a function of their owl-like facial ruff that can reflect sound.

Scan the open fields and low lands next time you're out in the park and you are sure to find the Harrier gliding with ease.