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A retrospective perspective: evaluating population changes by repeating historic bird surveys

January 1, 2005

Acquiring an accurate picture of the changes in bird populations often involves a tradeoff between the time and effort required to complete the surveys and the number of years spent surveying the bird populations. An alternative approach to long-term monitoring efforts is to collect current data and contrast those with data collected earlier in a similar fashion on the same study site(s). To evaluate changes in bird populations, we repeated two extensive surveys, one in North Dakota (1967 vs. 1992-1993) and the other in the Platte River Valley of Nebraska (1979-1980 vs. 2001), where large areas of native vegetation had been converted to agriculture. We use these examples and others from the literature to illustrate the advantages and disadvantages of using historical data as a frame of reference for population changes.

Publication Year 2005
Title A retrospective perspective: evaluating population changes by repeating historic bird surveys
Authors Lawrence D. Igl, Douglas H. Johnson
Publication Type Report
Publication Subtype Federal Government Series
Series Title General Technical Report
Series Number GTR-PSW-191
Index ID 2000143
Record Source USGS Publications Warehouse
USGS Organization Northern Prairie Wildlife Research Center