Friends of the Swainson’s Hawk is dedicated to the survival and recovery of the California Sacramento/Central Valley population of Swainson’s Hawk. We want to see this population flourishing in our region for all the generations to come. The California population numbers between 700 and 1,000 breeding pairs, roughly 10 percent of the historic population. Our region's Swainson's Hawk population numbers less than 1,000 and is vulnerable to extinction in California, due primarily to habitat loss. It is concentrated in Yolo, Sacramento and San Joaquin Counties and has no known interaction with other populations. Click on FAQ for more information about Swainson's Hawks.

Most of the world’s Swainson’s Hawks nest outside of California and migrate to South America each year. This population is referred to as the Great Basin or Great Plains Swainson’s Hawk population. You can find lots ofinformation on this population of 450,000 plus hawks on the web. They do not breed with California Swainson's Hawks, nor do they winter in the same locations.

The Swainson's Hawk of the Central Valley . . . 10 mg video . . . .2.4 mg video
o are found primarily within 70 miles of downtown Sacramento between March and September.
o are 18-21 inches long, males smaller than females and tend to be light as compared with dark females. Known for aerodynamic skill and long distance flying.
o nest in tall trees, often near rivers, creeks and canals, close to alfalfa, row crops, grasslands, and pasture lands.
o feed primarily on small rodents and insects. Very adaptable to agriculture. Follows agricultural operations to take advantage of prey exposure from plowing, discing, and burning.
o Migrate primarily to western Mexico (60%); also can migrate to Colombia (18%) and as far as northern Argentina (22%).

Wildlife biologists in the Sacramento area, including Mike Bradbury, Jim Estep and Dick Anderson have tracked migratory patterns by outfitting hawks with satellite transmitters. This group, and their colleagues collectively known as the Swainson's Hawk Technical Advisory Committee, have made available information, photographs and diagrams on this and linked pages. The most recent migration study --Owen's Valley-- is described in the link below.

Summary of migration study results from Mike Bradbury, 1999.
Maps of migration patterns of Swainson’s Hawk courtesy of Swainson Hawk TAC
Trip Reports by FOSH, Visits to Swainson's Hawk Mexican wintering grounds: 1998 Report; 2007 Report

Map of nesting range in Central California, courtesy of Swainson's Hawk TAC

Owens Valley Migration Study 2003