|
Evaluation of Midwinter Bald Eagle Counts
Completed
Web Site:
http://ocid.nacse.org/nbii/eagles/
Each January, several hundred individuals count eagles along standard, non-overlapping survey routes as part of a nationwide Midwinter Bald Eagle survey. The USGS assumed responsibility for overseeing the count in 1992. Objectives were to establish an index to the total wintering bald eagle population in the lower 48 states, to determine eagle distribution along a standardized survey route and period, and to identify previously unrecognized areas of important wintering habitat. A new analysis using the count data from 1986 - 2005 shows counts of wintering bald eagles increasing nationwide at a rate of 1.7% per year. Increases in counts over the 20-year period were highest in the northeast portion of the United States, with a 6% increase each year. In contrast, counts in the southwest portion decreased 1.2% each year over 20 years. Seventy-six percent of survey routes north of 40 degrees latitude had increasing count trends, but only 50% of routes south of 40 degrees latitude showed increasing trends. In April 2007, the USGS established a partnership with the U.S. Army Corps of Engineers to maintain the long-term, national coordination of the survey, data analysis, and reporting. For more information, see http://ocid.nacse.org/nbii/eagles/.
Website- The Midwinter Bald Eagle Survey Results and Analysis 1986-2005 [Link], Steenhof, K., Bond, L., Dunn, L.L. Steenhof, K., Bond, L., Bates, K.K., Leppert, L.L., 2002, Trends in midwinter counts of bald eagles in the contiguous United States, 1986-2000: Bird Populations, v. 6, p. 21-32. [Highlight] [FullText] Catalog No: 1196 Kaltenecker, G.S., Steenhof, K., Bechard, M.J., Munger, J.C., 1998, Winter foraging ecology of bald eagles on a regulated river in southwest Idaho: Journal of Raptor Research, v. 32, no. 3, p. 215-220. [FullText] Catalog No: 500
Midwinter Bald Eagle Counts, 1986-2005
Fitzpatrick, Martin - Deputy Center Director
Phone: 541-750-1032
Email: Martin_Fitzpatrick@usgs.gov
 |
