Cooperative Waterfowl Research - W-80-R 
Vol. 24, Mo. 2 
Page 5 
F. C. Bell rose, S. P. Havera, 
G. A. Perkins, H. K. Archer 
Each year state and federal biologists and qualified volunteers across the 
nation brave the January weather to conduct the Winter Waterfowl and Eagle 
Survey by land, water, and air. This cooperative nationwide survey begins the 
first Monday of the year and is completed whenever local weather conditions 
permit during the following k days. This census serves as a rough index to 
yearly changes in the populations of ducks, geese, swans, coots, and bald eagles 
and also delineates their winter distribution. 
In Illinois, Robert Crompton of the Havana Laboratory participated during 
January in the Winter V/aterfcwl and Eagle Survey by aerially censusing the 
Illinois and Mississippi River valleys and various selected reservoirs and 
cooling lakes throughout the state. Illinois winter censuses vary substantially 
from year to year because of weather; therefore we have compared the 1981 totals 
with 1976-80 5~year averages for evaluation. 
Ducks surveyed in the Illinois River valley in winter I 98 I totaled 172,000, 
a decrease of 17% from the 5-year average. Conversely, in the Mississippi River* 
valley there were an estimated 162,000 ducks, a 15% increase over the 5-year 
average. Censuses of reservoirs and cooling lakes across the state revealed a 
W increase in birds in northeastern Illinois and a 30% decrease in the central 
and southern part of the state. The total number of ducks in the Illinois 
winter survey decreased 7% in 1931 from the 1976-80 average, a smaller reduction 
than might be expected from the low totals for fall I 98 O (Ml/RL 24(1):6). 
Twenty three hundred Canada geese, 1,000 of which were the giant race, were 
observed on the Illinois River valley winter survey as compared to 24,000 on the 
Mississippi River. These totals represented a 12% decrease and a 65 % increase, 
respectively, from the 5-year averages. Canada goose numbers were up slightly 
to 65,000 on the cooling lakes and reservoirs in central and southern Illinois 
and increased 10% statewide over the 1976-80 average. Few snow geese and 
insignificant numbers of coots have been censused in the 1 976 - 8 1 winter surveys. 
The 267 bald eagles counted in the Illinois River valley during the 1981 
winter survey represented a 5% increase over the 1976-80 average. In the 
Mississippi River valley, bald eagle numbers were up 15% to 437 over the 5-year 
average of 380. Only small numbers of bald eagles disperse to cooling lakes and 
reservoirs in Illinois and contribute little to the statewide population. 
The 1981 survey indicated a slight shift in the winter distribution of 
waterfowl from the 1976-SO average. Ducks and geese were more concentrated in 
the Mississippi River valley and less abundant in the Illinois River valley. 
The use of cooling lakes in northeastern Illinois by all species of waterfowl 
increased, whereas the cooling lakes and reservoirs in central and southern 
Illinois were used less by ducks and about the same by Canada geese. 
Results from the Winter Waterfowl and Eagle Survey will provide a better 
understanding of population dynamics and distribution of the censused species. 
