Behavioral ecology of the Swainson's Hawk (Buteo swainsoni) in Washington

Technical Report · Mon Dec 01 04:00:00 EST 1980

DOI:https://doi.org/10.2172/6600005· OSTI ID:6600005

Fitzner, R E

This study examines the breeding ecology and behavior of the Swainson's Hawk (Buteo swainsoni) on its breeding ground in southeastern Washington. Seasonal movements and distribution of the buteo are also described. The birds were observed from blinds, or filmed by Super-8mm time-lapse cameras, during courtship, nest building, egg laying, incubation, and nestling and post-fledging development. Food habits were examined during the nestling and post-fledging periods. Snakes, especially the abundant Western Yellow-bellied racers, were a prey staple, and insects became an important food source during the post-fledging period. It was apparent that Swainson's Hawks feed on smaller and more diverse prey than sympatric buteos (Red-tailed and Ferruginous Hawks), thus reducing competition with neighboring congenerics. Interactions with buteos and other raptor genera were observed, and nearest neighbor distances measured. Organochlorine pesticides in prey species consumed by Swainson's Hawks are concentrated from prey to predator through the food chain. The hawk pellets (regurgitated castings) would contain those concentrations and could easily be monitored without sacrificing any part of the food chain.

• Research Organization: Battelle Pacific Northwest Labs., Richland, WA (USA)
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 6600005
• Report Number(s): PNL-2754
• Country of Publication: United States
• Language: English

Related Subjects

510100* -- Environment
Terrestrial-- Basic Studies-- (-1989)
54 ENVIRONMENTAL SCIENCES
ANIMALS
BEHAVIOR
BIOLOGICAL ACCUMULATION
BIRDS
DIET
ECOLOGY
FOOD CHAINS
HABITAT
NORTH AMERICA
PACIFIC NORTHWEST REGION
PESTICIDES
PREDATOR-PREY INTERACTIONS
REPRODUCTION
USA
VERTEBRATES
WASHINGTON