Eagles flock to Mighty Mississippi

SPRINGFIELD – Bald eagles gravitated toward the Mississippi River this year according to counts compiled by participants in the annual Mid-Winter Bald Eagle Survey.

The largest population of the eagles spotted were found along the Mississippi River (73 percent of the overall total), followed by 19 percent of the count found on the Illinois River and 8 percent sighted on the remaining survey points. Surveyors reported that 63 percent of the total eagles counted were adults and 33 percent were immature. An eagle’s white head and tail may not appear until they are nearly five years old. This field mark is not always clearly visible depending on the eagle’s location and movements; therefore a small number (5 percent) were listed as “unaged.”

Those who helped count eagles braved extremely cold temperatures earlier this winter to conduct the annual count along the Mississippi, Illinois, Kaskaskia and Wabash rivers in Illinois. Additional survey points at Crab Orchard Lake, Horseshoe Lake Conservation Area and Carlyle Lake combined for a total of 45 possible survey points.

The counts reported for 2010 total 1,185 eagles. Surveyors noted that 95 percent of the water surface was frozen and that several of the survey points were not safely accessible due to high river levels and flooded roadways. Over the last five Mid-winter Bald Eagle Surveys, 2,922 were counted in 2006, 1,920 in 2007, 4,292 in 2008 and 3,030 in 2009.

Most of the eagles that spend the winter in Illinois nest in the northern Great Lakes states and Canada. The open water in our large rivers and available fish make Illinois an important wintering area for the birds.

Many of the volunteers remarked that 2010 was harsher than previous years and some commented that heavy fog interfered with their counts. “Our volunteers here in Illinois repeat this process year after year, braving terrible winter conditions,” commented Tom Clay, Executive Director, “without their dedication this survey could not go on.”

This annual survey, coordinated by the Illinois Audubon Society was taken between the dates of December 30, 2009 to January 13, 2010. Nationally, this effort is conducted by the U.S. Army Corps of Engineers (USACE). The goal of the survey is to maintain the long-term, national coordination of the surveys collected, analysis of that data, and reporting the results.