NORTHERN HARRIER
by Rudy Stutzmann, No 1 / 1999
You have seen them flying low 10 to 20 feet over the ground coursing their hunting territory ready to pounce on any unsuspecting prey that they might suddenly come upon. Flying slowly, buoyantly rising and falling with the wind gusts or ridge soaring along the dunes adjacent to Ocean Parkway or maybe methodically flapping in unhurried half wing beats on calm days, the harrier hawk is forever on the move, efficiently using whatever advantages the air can give it to stay aloft and hunt for food.
The Northern Harrier, circus cyaneus, is a member of a worldwide genus of 9 or 10 species and the only one living in North America. In its seasons it can be found from Labrador to Alaska in the north, and to the south it inhabits all of the contiguous 48 states.
Possibly because of its slow flight and extensive northern breeding range this hawk has the longest migration season of any raptor. At Hawk Mountain, Pennsylvania, which has kept a daily migration count of raptors passing its ridge top site since 1934, the young birds start moving southward in mid August while the mature birds linger at their nesting and hunting areas. The far northern birds from eastern Canada might not be seen till the end of November. Because their wintering territory covers most of the continental United States the harriers wintering here could have summered in Canada while our summer residents possible are now far south of the Mason Dixon Line. Unfortunately, we just don’t know.
Each species of raptor is superbly designed to hunt in an environment that gives it the greatest opportunity for success. This explains why the Northern Harrier until 30 or so years ago was named the Marsh Hawk. (At the same time the Sparrow Hawk became the Kestrel.) Flying low over the open fields, swamps, and meadows the harrier whirls and suddenly drops to the earth to catch voles, mice, frogs, rats, small snakes, and occasionally a distracted bird. Recent research indicates that harriers use sensitive hearing to locate prey by sound just as owls do. This would explain the similarity of their facial disks, which we know in owls, helps to focus sounds to their ears.
Ten years ago I could count on observing 10 to 15 harriers on a drive from Jones Beach to Captree. Now I see 2 to 5 such birds. You, too can observe them if you look AND know what to look for.
Unusual among hawks the sexes are dissimilar in color. The mature male is grayish on top, white on the bottom and has black wing tips. His mates (YES) have dark brown heads, backs, and upperwings and are streaked with brown below. All immatures are brown above and have a “buffy cinnamon” color below. In other words they look like their mothers with a hint of dark reddish color on their breasts. But the one identifying mark on all harriers, which is unique to them, is a large white patch on their rump. This mark at the base of the tail is easily seen when the bird wheels and turns in flight. Also, relative to wing span and body length, this hawk has the longest tail of any raptor. The Peterson Field Guide for Hawks gives these measurements: Male - length 16” to 18”, wingspan 38” to 43”; Female - length 18” to 20’, wingspan - 43” to 48”. The above statistics show a common trait of all hawks, namely that the female is one quarter to one third larger than the male. While this size differential may seem strange, nature in its wisdom has provided a way for a hunting species to have access to a wider range of prey, especially while a brood of young is in the nest. A male is capable of carrying a rat in its talons but only the bigger female can transport, say, a rabbit or possibly a muskrat to the nest.
Speaking of nests, harriers are unique among North American hawks in another respect; namely the males are regularly polygamous. A male may mate with as many as three females and will support and defend each nest. Another singular feature of this bird is that it nests on the ground. I came across such a nest at Gilgo East last year while helping to erect an osprey pole. It had survived the winter intact, being on the highest spot in the meadows, a foot or eighteen inches higher than the rest of the area. What instinct or intelligence guided her to build her nest just there?
Besides the unique white patch on its rump and its habit of flying low over the ground, another visual identification is its shape in the air. It is “long, lean, lanky, narrow winged, and long tailed”. The wings angle up in a noticeable dihedral and because of its light wingloading it appears unstable in flight, rocking one wing then another as it reacts to the smallest of wind gusts. They remind one of turkey vultures which also have a distinct wing dihedral and show the same rocking, unstable flight pattern.
Come the middle of September the first hints of fall are in the air. The humid southwesterlies change to northwesterlies and the air is drier, crisper. The air from the Gulf is being replaced by air from central Canada. Nature’s cycles do not change and now it’s time for the winged ones to leave the nesting sites and head to more hospitable climates. The young birds have fledged; they have learned to fly and feed on their own. Now they must face the greatest test of their lives. Sometimes in flocks with their parents and often on their own they must fly south along aerial flyways that have been genetically imprinted into their brains for thousands of years. And with this mass of avian life comes their nemeses, the hawks, which must follow their food supply if they, to are to survive.
To see a small but fascinating scene from this great annual fall event you need only go to parking lot #5 at Robert Moses State Park and walk east a quarter mile to the point where the road makes a U-turn and heads west again. From mid September to the end of November the North East Hawk Watch identifies and counts each hawk as it passes through. The 1997 annual report lists, among others, 2 bald eagles, 247 sharpshins, 1148 American kestrels, 994 merlins, 126 peregrine falcons and 83 harrier hawks. The little falcons, the kestrels and merlins come in low to stay below the stronger winds above. They weave and dart always looking for prey but never slowing down. You may have one of these in sight for one minute before it passes. The harriers search for each gust of lift, accelerate through the eddies and hug the low ground to go below the quartering headwind. They plod, seemingly without effort, but they, too, pass on; it just seems to take forever, which may be three or four minutes. Their apparent complacency has no limits. They acknowledge a car’s right of way if near a highway but no more. Neither harassing crows nor redwing blackbirds appear to disturb their flightpath. In comparison, the merlin, a small falcon from Canada mostly, has an attitude, to say the least. He thinks that the sky is his and resents all who are in his airspace, other hawks included. (Except for the Big P that is, no bird, not even the bald or golden eagle challenges him.) Even crows become quiet and passive when a merlin is headed their way. For a bird weighing, maybe, one seventh to one tenth of a crow that says a lot.
Of all the raptors there is one and only one that stops idle chat, that makes all hawk watchers focus on it till it has disappeared out of sight and which we envy and sometimes wish we could switch places with, if only for a day. That bird is the Peregrine Falcon. Deceptively fast and very strong it powers through headwinds on days that force all other hawks to sit it out in the trees.
The Tundrius form of the peregrine is a migrant down our barrier islands. They are from the far north, many nesting in the cliffs along the north west coast of Greenland far above the Arctic Circle. Through the use of telemetry, tiny transmitters are attached to the bird’s bodies and we are able to track their prodigious flights. One bird left the east coast of the US and flew direct to Bermuda, and after resting flew direct to the Bahamas. Another peregrine, instead of following the curvature of the coastline of the south east states took the direct line over the ocean and came ashore at Jacksonville, Florida a day and a half later. His next stop was at Key West. When last tracked he was headed towards Cuba. You just know that the Caribbean did not pose any threat to him.
So some quiet winter day while driving along Ocean Parkway keep an eye out for that low flying hawk with the white patch on its rump and with a dihedral shape to its wings, and if its wing tips rock up and down in apparent instability, then you have seen a harrier hawk.
P.S. Our harriers are not the only raptors spending the winter with us. There is a resident female peregrine which spends many days and nights on top of the Jones Beach water Tower. She sits on the side away from the heavy wind and rain. A coopers hawk has also been a winter resident for years. It knows where all the bird feeders are at Gilgo and West Gilgo. A kestrel sits on the telephone poles between Cedar Beach and Oak Beach, and a rough legged hawk has taken up residence between Zack’s Bay and Tobay Beach. Also, rough legged and redtail hawks can be seen sitting in the bare trees along Meadowbrook Parkway south of Route 27A.