Swainson's Hawk

Buteo swainsoni

Large flocks of Swainson's Hawks migrate between their winter grounds in southern South America and breeding grounds in the western North American Plains. While their normal breeding habitat is open prairie land and forested riparian corridors, they also nest in trees near farmsteads and towns. Because they are very tame, and frequently perch near roadsides, uninformed target shooters often shoot them (Terres 1987). They usually build their medium-sized, shallow nests on smaller branches away from the main tree trunk.

In 1907 Widmann reported one Lawrence County site and several in adjacent states. The Swainson's Hawk is currently listed as Endangered in Missouri.

Code Frequency

Swainson's Hawks can easily be detected and identified as they soar on slightly raised wings. Nests are easily located in late April before becoming shrouded by leaves. Because most Atlasing effort occurred later, Swainson's Hawks may have bred undetected in some blocks where found.

Distribution

In addition to the locations shown on the map, several nests located outside blocks produced young between 1986 and 1992. These nests were located in suburban Springfield near houses and schools, and were scattered throughout the surrounding counties in tree rows between mixed croplands and pastures. Summering Swainson's Hawks have been reported sparsely from western Greene County and southern Vernon County in southwest Missouri. Robbins and Easterla (1992) reported them in several counties in west central Missouri with Barton County being the most frequented area.

Abundance

Scattered records from southwestern Missouri indicate perhaps as many as 5-10 nesting pairs within the state annually.

Phenology

The Swainson's Hawk arrives in March and April and departs in late August and September (Robbins and Easterla 1992). Adults on nests have been observed by the authors in late April and early May.

Breeding Evidence

Reported in 8 (<1%) of 1,207 blocks.

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