Broad-winged Hawk, Buteo platypterus
Late September, specifically September 22 in 2020, marks the autumnal equinox. This event marks the moment the Sun crosses the celestial equator, an imaginary line in the sky above Earth’s equator, from north to south (and south to north in March for vernal or spring equinox). September also marks the beginning of “Hawk Watch,” which extends through November in Michigan. Hawks, as well as other raptors and Turkey Vultures, are counted, largely by trained volunteers, at five sites in the state; Detroit River, Whitefish Point, Mackinaw Straits, Brockway Mountain, and Port Crescent. Each of these sites is strategically chosen since they are locations where the birds can cross relatively short distances across large bodies of water that would otherwise be difficult for soaring birds to travel without expending precious energy. The raptors depend on the rising thermal air currents from the sun-warmed Earth to provide lift and allow them to soar large distances. All that said, sunny days are best for these birds to travel and the best time to sight them traveling as they travel south to warmer climates for the winter.
Broad-winged Hawks are an interesting species locally for a few interesting reasons. The first reason being they are usually seen only for a few weeks during spring and fall migration. Since they spend summers nesting and raising young in dense forests throughout northern and eastern North America but mostly in boreal forests in Canada, they winter in Southern Mexico and South America. While some individuals accept living near humans, even those birds avoid human settlements and interactions. Local sightings are rare except during their long-distance travels. They make their migration flights in large flocks that are commonly called “kettles,” which often contain hundreds of individuals at such heights that they appear as specks of pepper to the naked eye. The fall migration is larger due to the addition of new fledglings, and it typically peaks in Michigan from mid-to-late September. Research has shown that they usually migrate about 4,300 miles, traveling an average of 70 miles per day. When migrating to South America, they avoid crossing large bodies of saltwater. There are several small populations on the Caribbean Islands that are year-round residents, including endangered sub-species with a population of about 100 birds in Puerto Rico.
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Like many raptors, the Broad-winged Hawk is relatively drably colored, but they are easily distinguished from other hawks by a few features. The adult’s body is dark brown with a white belly and chest with horizontal rufous barring. The short, broad wings come to a distinctive point and are white underneath with a dark border on the wingtips and trailing edge. The tail is relatively short with distinctive dark banding. There are two types of coloration; a dark morph with fewer white areas and a light morph that is pale overall. Like most raptors, the females are slightly larger than males. They average 15 inches in length, have a wingspan of about 35 inches, and weigh an average of 16 ounces, approximately the size of the American Crow. Their call is a high-pitched and whistle-like “kee-ee” and is used for communication with their mate and offspring and displays toward intruders or threatening predators, including larger raptors that feed on adults and many mammals that may eat the eggs and young.
They are carnivorous feeding on small mammals, frogs, lizards, insects, small birds, snakes, and crabs. Unlike many raptors, they give special attention to food preparation and will skin frogs and snakes and pluck birds prior to consumption. They rarely drink water and are able to survive with the water present in their food.
If you would like to see a Broad-winged Hawk, I recommend you visit Lake Erie Metropark in Gibraltar, Michigan on a mostly sunny day during September or October. You can also check Detroit River Hawk Watch monitoring at detroitriverhawkwatch.org for count data, events, hawk identification, and other news about migration.
If you wish to learn more about birds you are welcome to attend Blue Water Audubon meetings held at The Point, 5085 Lakeshore Rd, in Fort Gratiot. Please visit our Facebook page, “Blue Water Audubon Society”, for meeting details and be sure to friend us.
Tom Dennis is a free-lance writer, passionate birder, zoologist, creation scientist, and naturalist.