When I think of the northern harrier, also called marsh hawk, a couple of experiences come to mind. One occurred in east central North Dakota while conducting my graduate wildlife research project. On that particular day I flushed a female harrier from a patch of tall grass near a clump of hawthorn trees.
I could tell the bird was a female by her color—females are brown, males are gray—and of course by the diagnostic white rump patch that both sexes have. After a brief search, I found her nest with five white eggs inside. Northern harriers build their nests on the ground, which is an uncommon nesting behavior amongst species of hawks.
On another harrier encounter, I was hunting sharp-tailed grouse in Beltrami County along the edge of a hay field and brushy area. I happened to be taking a break at the time, looking across the brushland, when I spotted a harrier flying slowly above the willows. The bird appeared to be hunting.
A moment later, evidently noticing me, the hawk abruptly turned and began flying directly toward me. When the harrier reached me, it circled scarcely a dozen feet above my head looking directly into my eyes. This was the first time I became acutely aware of the owl-like face of the northern harrier.
Now here’s one of the fascinating facts of this elegant raptor. Harriers have a curved, facial ruff similar to that of owls’. Such an adaptation helps northern harriers collect and funnel the faint sounds of scurrying mammals and other prey to the hawk’s ears as they fly a few yards above the ground. In other words, a harrier’s face is a sound reflector, an amplifier if you will.
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Indeed, along with their keen vision, harriers rely heavily on their acute sense of hearing to find and capture prey, whereas other species of hawks are mostly vision hunters. As harriers fly low across marshes and grasslands, wings held in a telltale V-shape while banking left and right, one can easily see firsthand why harriers are such efficient and successful hunters.
Northern harriers will soon be back in Minnesota. And when they return, courtship flight displays will follow. One of the more spectacular aerial rituals in the bird world, courting male harriers will fly to great heights to perform sky dances for an observing female. Diving from some 1,000 feet or higher, male harriers fly in what’s often described as undulating, roller coaster-like flights that can cover a distance of one-half mile or further from start to finish.
Interestingly, male harriers frequently have more than one mate at a time, often two, but sometimes as many as five, depending on the abundance of food. Nest building is shared duty, although it’s the female that arranges vegetation inside the nest bowl to fit her larger body (females are larger than males). After four or five eggs are laid, the female begins a month-long incubation period. Her mate will do most of the hunting during this time and brings food to the nest for his mate to eat.
On the harrier menu is an assortment of prey items. Hunting primarily small rodents like mice and voles, northern harriers also prey on ground squirrels, songbirds, snakes, frogs and toads, and sometimes even larger prey such as rabbits.
Since harriers nest on the ground, nest predation by predators like raccoons, skunks and foxes do occur on occasion, albeit rare. Harriers fiercely defend their nesting territories and are fearless when faced with potential threats. Northern harriers don’t tolerate other harriers within their breeding and nesting territories either. Each sex will chase other harriers away.
I’m looking forward to observing northern harriers once again. Their graceful teetering flight to and fro and low to the ground as they hunt for prey is a welcome sight each and every year. A quiet hawk, northern harriers are among the most unique of Minnesota’s many raptors as we get out and enjoy the great outdoors.
Blane Klemek is a Minnesota DNR wildlife manager. He can be reached at bklemek@yahoo.com.
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