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Assessing Threats to the Swainson's Hawk
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Swainson’s Hawks generally breed throughout North American grasslands and migrate south to winter in specific regions in Argentina. International concern exists about massive die-offs of these hawks on their wintering grounds due to pesticide poisoning in 1995-1996. Population numbers of Swainson's Hawks are declining in many portions of their range. This study radio-tracks Swainson's Hawks in breeding grounds in North America and in wintering grounds in Argentina. This research indicates the extent to which North American nesting populations use natural and modified habitats across the nonbreeding-season range. USGS scientists are also investigating the extent to which local nesting birds might be threatened by habitat loss and environmental contaminants in South America. Specifically this study describes migratory routes, important stopover sites, and staging areas used by Swainson’s Hawks. Results help relate hawk distribution to land uses, environmental contaminants, and other threats.
Kochert, M.N., McKinley, J.O., 2008, Use of body mass, footpad length, and wing chord to determine sex in Swainson's hawks: Journal of Raptor Research, v. 42, no. 2, p. 138-141. [Highlight] [FullText] Catalog No: 1821 Varland, D.E., Smallwood, J.A., Young, L.S., Kochert, M.N., 2007, Chapter 13- Marking techniques In Raptor Research and Management Techniques: Blaine, WA, Hancock House, p. 221-236. [FullText] Catalog No: 1976 Canavelli, S.B., Bechard, M.J., Woodbridge, B., Kochert, M.N., Maceda, J.J., Zaccagnini, M.E., 2003, Habitat use by Swainson's Hawks on their austral winter grounds in Argentina: Journal of Raptor Research, v. 37, no. 2, p. 125-134. [Highlight] [FullText] Catalog No: 1208 Goldstein, M.I., Bechard, M.J., Parker, M.L., Kochert, M.N., Lanusse, A.E., 2000, Abundance, behavior and mortality of Buteo swainsoni near San Francisco, Cordoba, Argentina in 1997: Hornero, v. 15, no. 2, p. 117-121. [FullText] Catalog No: 676
Kochert, Michael N. - Research Wildlife Biologist
Phone: 208-426-5201
Email: mike_kochert@usgs.gov
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