Studies and Surveys
- 20mm Survey
- Fall Midwater Trawl
- Fish Salvage Monitoring
- Historical Surveys
- San Francisco Bay Study
- Smelt Larva Survey
- Special Studies
- Spring Kodiak Trawl
- Striped Bass Study
- Sturgeon Study
- Townet Survey
- Zooplankton Study
Other BDR Links
7329 Silverado Trail
Napa, CA 94558
2109 Arch Airport Rd
Stockton, CA 95206
Acting Regional Manager:
Stanislaus River Report
Return to Report Index
Stanislaus River Basin and Calaveras River Water Use Program|
Threatened and Endangered Species Report - March 1995
Bay Delta and Special Water Projects Division, CA Dept. of Fish and Game
Sharp-shinned HawkAccipiter striatus
California Department of Fish and Game "Species of Special Concern"
Life HistoryThis jay-sized hawk is small and slim bodied. It measures 10 to 14 inches in length and has a wingspan of 20 to 28 inches. The sharp-shinned hawk can be distinguished from the Cooper's hawk by its shorter and squarer tail which often appears notched when it is folded. Additionally, the sharp-shinned hawk has a proportionately smaller head and neck. The adults have a dark back and rusty-barred breast. The immatures are dark brown above and streaked with rusty colored underparts. The sexes are very similar in plumage but the females are noticeably larger than the males (Clark and Wheeler 1987).
Breeding is conducted April through August with a peak in activity in late May, June, and July. This hawk usually nests in dense pole and small-tree stands that contain conifers and are cool, moist, and well shaded. These stands frequently have little cover and are near water. The nest is a cup or platform that is in dense foliage against a tree trunk or in the main crotch. The nest is usually placed between six to 80 feet above the ground and is the most conspicuous nest of all the accipiters (Call 1978). The nests are usually located within 275 feet of water. The clutch averages four to five eggs with an incubation period of 34 or 35 days which is shared by both adults. The young fledge in approximately 60 days.
North facing slopes that contain plucking perches are a critical requirement for the sharp- shinned hawk. Plucking sites are locations, usually within the nesting territory, where the hawk perches to deplume and dismember its prey (Evans 1982). Roosting cover of intermediate to high canopy forests is also a requirement, but it will nest is dense stands that are in close proximity to open areas.
The diet of the sharp-shinned hawk is primarily small birds that are usually no larger than jays. Small mammals, insects, reptiles, and amphibians are also taken.
Findings and ConclusionsHabitat loss is the primary reason for decline of this hawk.
The sharp-shinned hawk occurs along the Stanislaus River in migration and as a winter resident (Reeve pers. comm.). Any project that would affect flows of the Stanislaus River and thus the riparian corridor, would impact the sharp-shinned hawk.