WunderPhotos®

The photo of this hawk was taken at the Wildlife Rehab Centre in Ils Des Chenes, Manitoba. The Swainson's Hawk is named after William Swainson, a British naturalist. It is colloquially known as Grasshopper Hawk or Locust Hawk, as it is very fond of locusts and grasshoppers and will voraciously eat these insects whenever they are available. Their breeding habitat is prairie and dry grasslands in western North America. They build a stick nest in a tree or shrub or on a cliff edge. This species is a long-distance migrant, wintering in Argentina. It is a breeding resident almost throughout North America. The Swainson's Hawk ranges in size from 17–22 inches long and weighs 1.1–3.7 lbs. There are two main color variations. Over 90 percent of individuals are light-morph; the dark morph is most common in the far west of the range. The Swainson's Hawk is probably the longest migrant of any North American raptor. The flight from breeding ground to South American pampas in southern Brazil or Argentina can be as long as 14,000 miles. Each migration can last at least two months. They leave the breeding grounds from August to October. Fall migration begins each clear day on which a wind blows in the general direction of travel. Birds gain altitude by soaring in circles on a rising thermal and then set their wings and close their tails as they glide, slowly losing altitude until they find another thermal and rise with it. Thus, waves and small groups are strung out across the sky. The birds gradually head southwards toward Central America where virtually the entire population funnels through the Isthmus of Panama. Concentrations over locations like Ancon Hill, Balboa, and Panama City are spectacular. In the Andes, it migrates along a narrow corridor and rarely strays off course; for example, it was only recorded in the Serranía de las Quinchas of Colombia – just 100 km or so off its usual migration route – in 2000/2001. The habitat of Swainson's Hawk consists of open and semi-open country – deserts, grasslands and prairies – in both its breeding and wintering ranges. It favors wild prairie, hayfields, and pastures over wheat fields and alfalfa fields, which may offer its prey too much cover. It requires elevated perches for hunting and a supply of small mammals such as young ground squirrels as prey for its nestlings. The breeding distribution of the Swainson's hawk is tied very closely to the distribution of various small mammals for this reason. In Saskatchewan, for example, the distribution of Richardson's ground squirrel and the Swainson's hawk are precisely the same.