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SWAINSON'S HAWK (Buteo swainsoni) STATUS Federal: None State: Threatened Other: CNDDB Special Animal DESCRIPTION The plumage of Swainson's hawks is extremely variable and there are many different recognized color phases. The body length averages 21 inches and the wingspan is approximately 52 inches. Although this species is about the same size as a red-tailed hawk, the Swainson's hawk can be easily distinguished by its long, narrow pointed wings and the gray-brown tail with about 6 narrow dark bands and a wider dark terminal band. The Swainson's hawk is also somewhat smaller than the Red-tailed hawk. DISTRIBUTION Swainson's hawks breed in Canada and the western United States and winter in southern South America (principally Argentina). Currently, Swainson's hawks are summer breeders in California with approximately 80% of the pairs nesting in the southern Sacramento and northern San Joaquin Valleys. Swainson's hawks arrive in California between late March and early April. The nesting season occurs from May through mid-August. This species generally migrates through the interior of California in late August through September (CDF&G, 1988). Historically, Swainson's hawks were common nesters from lowland southern California and southern coastal valleys through the Central Valley and up into the Great Basin region of northeastern California. There were also smaller nesting populations in the southern Sierra Nevada/White Mountains and the Mojave/Colorado desert region(Bloom,1980). HABITAT PREFERENCES Swainson's hawks typically utilize tall, densely foliaged trees such as cottonwoods and oaks as nest sites. These sites may occur in both agricultural fields and riparian areas. Foraging habitat includes native grassland, pastureland and alfalfa fields. Occasionally during the fall, large flocks of migrating Swainson's hawks gather in agricultural fields in the Central Valley to forage on grasshoppers and other large insects that are easily captured in recently plowed or mowed fields (Beedy and Granholm, 1985; Ehrlich,Dobkin and Wheye, 1988). Nests are sometimes used perennially.