All about Swainson’s Hawks

Scientific Name: Buteo swainsoni. This literally translates to their common name, Swainson’s Hawk. They are named for the British naturalist, William Swainson, who had first illustrated the hawk. However, Swainson had mistaken it for a subspecies of the Common Buzzard. It was French biologist Charles Lucien Bonaparte who correctly identified the hawk as its own species and chose to name it after Swainson.

Description: Swainson’s Hawks have two main color morphs. The more common light morph has a white/light cream color belly and under the chin with a reddish chest and dark brown feathers on the back, head and wings. The underside of the wings from shoulder to wrist has a distinct white patch on the upper half. The darker morph has a distinct rufous colored patch on the underside of their wings, instead of white and their brown feathers are darker, sometimes almost black. Dark morph Swainson’s Hawks also have an auburn colored belly. These hawks weigh between 800g and 1100g, with a wingspan of up to 49 inches.

Behavior: The Swainson’s Hawk is also commonly called the Grasshopper Hawk or Locust Hawk due to their affinity for insects. They will land in grassy areas to hunt insects while on foot. They mate for life and are known for being especially territorial of their nest-sites. The male will usually choose the nest-site, but both sexes may take part in nest-building, using sticks, twigs and other debris. Swainson’s Hawks will build nests in trees most of the time. However, southern nesting birds have been seen building nests in bushes only 3 feet off the ground. The female lays 1-5 eggs that will hatch after approximately 34 days. The nestlings begin to fledge around 22 days old- that’s just over 3 weeks old!

Diet: Mainly insects and small mammals. They have been known to eat birds and some reptiles as well.

Conservation: In the mid 1990s, Swainson’s Hawk populations plummeted due to the use of certain types of pesticides in South America. These pesticides not only killed off one of their major food sources, insects, but also poisoned many birds. Thankfully, the banning of those pesticides helped to turn the tide and slowly they rose back to better numbers. Currently the Swainson’s Hawk is a species of Least Concern on the IUCN Red List. They do continue to face difficulties with loss of habitat and the use of other pesticides. 

How you can help: Supporting legislation that protects wild habitats and prohibits the use of pesticides that affect wildlife. Planting native plants will also help encourage native insect species and increase prey for Swainson’s Hawks as well as many other species.

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