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Wisconsin Natural Resources magazine

Wisconsin Natural Resources magazine

February 1997

Falcon. Photo by Eugene and John Jacobs, © 1997

Talon show

Wisconsin's hunting hawks send this admirer soaring into raptures on raptors.

Christian W. Cold


Photo © Eugene and John Jacobs
Buteos | Accipters | Falcons | Hawk or owl?

Traveling down a rural road in central Wisconsin can be uneventful in mid-winter. The passing expanses of barren, plowed fields appear lifeless, relieved only by occasional stretches of yellow-brown grass.

"Idle land," some would say – a misnomer of enormous proportions. A bustling community lives within those protective mantles of sod and weathered plant residue. How do I know? There – up in that distant elm – I can see the dark vertical profile of a hunting bird, waiting in mute anticipation. It's a rough-legged hawk, a recent arrival from the far north.

Feathers fluffed to conserve energy, one foot tucked up into its dark belly feathers, the hawk appears aloof to its surroundings. Suddenly, the broad, fluffy profile becomes sleek, the head raised, alert. With partially opened wings the hawk steps off its perch and descends in a steep dive to the grass. A flash of feathers and the hawk disappears. Moments later the bird launches itself skyward, flapping heavily toward the elm. As the hawk cleans its beak on the perch, I realize it has just eaten something, probably one of several meadow mice whose brief story will conclude today.

Hawks are noticeably absent where intensive land use impoverishes the landscape. Some feed on an assortment of animals and can survive on whatever prey is available, while less adaptable hawks must move on to places that can supply their special dietary needs. The presence or absence of hawks can tell us a lot about the quality of habitat in an area. Occurring at low densities wherever they exist, hawks rarely have a significant impact on prey populations. Rather, it is the availability of prey that has the greatest influence in most predator/prey relationships.

A hawk is a raptor – Latin for "to snatch." The term refers to any bird with grasping feet and taloned toes. The design of the feet reveals the general occupation of each species of hawk, owl, eagle or osprey. Hawks with long toes are bird-catchers; they need long toes to snag something as fast as a bird. Short-toed hawks are mousers; they pounce cat-like on small animals. As for those hawks with large feet and black, grappling-hook talons...they're capable of capturing and consuming just about anything.

Buteos

Hawks are divided into several groups according to their flight profiles. Broad-winged birds soaring at lofty heights are typically classed as buteos.

The red-tailed hawk (Buteo jamaicensis) is Wisconsin's largest buteo. It's a heavily-built bird with large feet. Commonly found along woodland edges and open savannas, the red-tail is in strength and temperament the most powerful and spirited of the buteos. Where other hawks keep to the cover of trees, the red-tail will boldly swagger across an open field. The red-tail's menu features everything from insects to woodchucks. Ultimately, most adult red-tails become confirmed mousers, though they can switch to other prey should the ranks of mice thin.

Come October, another large buteo arrives in our state. The American rough-legged hawk (Buteo lagopus), an Arctic bird, comes to Wisconsin pastures and marshlands to pass the winter with meadow mice. With its feathered tarsus and small, specialized feet, the rough-leg must confine itself to areas where mice are abundant. Rough-legs are mottled shades of brown, with dark wrist patches and plenty of white on the tail. Juveniles sport a broad dark belly band; other individuals may be dark throughout. The rough-leg's habit of perching on tree tops or hovering in place over open fields will distinguish them at a distance. Buena Vista Marsh in Waushara County is one of the best places to observe rough-legged hawks in the state.

Hidden within mature riverbottom forests and swampy woodland lives another large buteo, the red-shouldered hawk (Buteo lineatus). More delicate than the red-tail, it prefers to hunt for small rodents, snakes, amphibians and the occasional bird rather than struggle with a kicking rabbit. Look for a banded tail, a rusty breast and shoulders, and a sickle-shaped panel of white on the primaries. The red-shouldered hawk has suffered from the fragmentation of large blocks of floodplain forest, and is now listed as a state-threatened species. When openings are created in red-shoulder habitat, feisty red-tails may move in and set up housekeeping, displacing the former tenants.

A near-replica of the red-shouldered hawk is the little broad-winged hawk (Buteo platypterus). About the size of a crow, the broad-wing is probably the most common summer resident hawk north of Wausau. A neotropical species, this snowbird gathers in great flocks, or "kettles" during September and departs for the tropics. The broad-wing prefers mixed forests of various sizes, especially near standing water. In these woodlands it finds large insects, snakes, frogs, toads and rodents. Listen for its faint, drawn scream – the only Wisconsin hawk whose voice trails up in pitch.

Accipiters

Some woodland hawks are classed as accipiters. With shorter wings and longer tails than buteos, accipiters are designed for rapid maneuvers beneath the tree canopy. Their long toes reveal a bird-eating habit, but mammals are well-represented in accipiter diets.

In general, juvenile accipiters are brown and they are easily confused with other hawks. As adults, the accipiters develop distinctive gray feathers on their backs (dorsal surfaces).

The largest, most powerful and aggressive accipiter is the northern goshawk (Accipiter gentilis). The "gos" is a massive bird of red-tail proportions but slimmer stature. Adults are slate-grey above and light beneath. Look for an almost-white brow line above each blood-red eye to quickly identify an adult gos.

Goshawk populations follow the cyclical ebbs and flows of snowshoe hare and grouse. Considered a rare bird wherever it is found, the gos prefers large, older stands (40 years or more) of mixed hardwoods and conifers for nesting. Once considered an "old-growth" species, the gos may also benefit from certain types of early successional woodlands. A mature aspen is often selected as the nest tree, probably due to the open flight path afforded by its broad, open crown. Aspen stands also support many of the prey species the goshawk prefers.

Sensitive to disturbance near its nest, the gos may abort a nesting attempt. The goshawk may be listed as a species of special concern or state-threatened status after more data is gathered on its distribution and density of the species in Wisconsin.

Smaller cousin to the gos is the Cooper's hawk (Accipiter cooperii). Formerly a state-threatened bird, the "Coop" recently emerged from its high-risk status when surveys revealed a significant distribution of nesting birds throughout the state. The Coop resembles the broad-winged hawk in size and color, but has a more streamlined profile and longer legs and toes. Fond of feeding on birds, the Coop also relishes chipmunks, small squirrels and young rabbits. Cooper's hawks may be found in a variety of woodland settings, including urban areas. They are common summer residents in many central Wisconsin communities.

Our smallest accipiter, the sharp-shinned hawk (Accipiter striatus), may be no larger than a robin. As with other accipiters, the female may be as much as 30 percent larger than her mate. A skittish little dynamo, the "sharpie" may be distinguished from the strikingly similar Cooper's hawk by its smaller size and distinctly squared-off tail. The sharp-shin keeps to the shelter of conifers where small birds may be ambushed.

Most sharp-shins breed in the boreal forests of Canada. Wisconsin nesters seek dense conifer plantations as far south as Waushara County. Sharp-shins are highly migratory, following their principal food source, small perching birds and songbirds. Come mid-September, migrating sharp-shins may be observed in large numbers near Duluth, Minnesota or along the Lake Michigan shoreline.

Falcons

American kestrel. Photo by Herbert Lange, © 1997
The beautiful but diminutive kestral or "sparrow hawk" hunts the roadsides and farmlands.

© Herbert Lange

Falcons are the elite members of the raptor corps. Equipped with large, dark eyes, streamlined profiles and long, sickle-shaped wings, most falcons favor open spaces. The American kestrel (Falco sparverius), a robin-sized bird of roadsides and farmland, is our most common falcon. Often seen on power lines the kestrel sits with teetering tail and bobbing head until a summer grasshopper or wintering mouse or songbird draws its attention. Over open fields, a kestrel may suspend itself with quivering wings above some small object of interest.

The male, or "tiercel," is adorned in tones of powder blue and brick red, with bold bands and crisp flecks of black-on-white; his display of color is rivaled only by a drake wood duck in full nuptial dress. Females are a rich rust with profuse, fine bands of black. A cavity nester, the kestrel typically selects an abandoned shelter of the northern flicker, a woodpecker. (The flicker has many of the same field markings as the kestrel.) Kestrels will quickly settle in properly designed and placed nest boxes.

The merlin (Falco columbarius), a pigeon-sized falcon formerly called the "pigeon-hawk," is an uncommon resident of Wisconsin. A bird of the northern forested lake country, the merlin is one of the few falcons that uses a stick nest. Males are dark grey, females are brown; both sexes lack the crisp markings of the kestrel. Identify a merlin by its dark coloring and boldly-banded tail, which is often splayed out before the bird perches. You'll see them in fall along Lake Michigan, following the migrations of other birds – the merlin's principal food.

The peregrine falcon (Falco peregrinus), a dark, crow-sized bird, was until recently considered extinct east of the Mississippi River. Pesticides interfered with the peregrine's reproduction. After the use of DDT was banned in 1972, peregrines began a gradual recovery. Today, with the assistance of falconers and captive breeding projects, peregrines have been reestablished through releases in Midwestern metropolitan areas, where tall buildings serve as surrogate cliffs. Peregrines attack pigeons and medium-sized birds by hurtling into the prey from a great height in a breathtaking "stoop." Arctic peregrines, a separate subspecies, may be observed along Lake Michigan in September.

Wisconsin's largest falcon is rarely encountered by the casual observer. The gyrfalcon (Falco rusticolus), enormous by falcon standards, may appear in either dark or light plumage. The gyrfalcon has a varied diet that includes larger birds and hares. Fond of ptarmigan on its Arctic homeland, the gyr has a predisposition to open-country sharp-tailed grouse and prairie chickens. Gyrs can sometimes be seen in winter near the Duluth/Superior harbor, patrolling the bleak coastline in search of gulls and pigeons.

Hawk or owl?

The northern harrier (Circus cyaneus) is an anomaly among hawks: It has the facial features of an owl. Alerted by sound, the harrier turns its head toward the subtle movements of rodents in tall grass, sedge meadows or cattail marshes. With acute vision and exceptionally long legs, the harrier sails just above the vegetation, stalling to deftly snatch some small morsel from the ground. Males are chalk-blue with long wings tipped in black. The females are brown throughout. Both sexes display a white rump patch in flight. Harriers make their nests on the ground – often in hay fields, which may be cut before the young can mature. Horicon Marsh in Dodge County and the Buena Vista Grassland in Waushara County are good places to observe harriers.

Whether buteo, accipiter or falcon, the sight of a hawk in flight stirs us. Scanning the landscape, cruising over the grass, hurtling down from the clouds like a feathered thunderbolt...witnessing a hawk in action is to witness a wonder of life.

Christian W. Cold is a DNR wildlife technician and educator who has spent 25 years on the wing surveying nesting raptors in the Great Lakes region. He has been a falconer since 1970.