. Distribution and abundance of winter populations of bald eagles in Illinois. Bald eagle. Illinois Natural History Survey Biological Notes No. 129 Southeast Alaska. Northwest Interior Maine/ Nova Scotia I \\ Florida Breeding Area Represented by Bandings Fig. migraioi \ |)"l) Scrviii- 1986) Oilohii icmM-rics (IS. lisli . U ildlile most likely to occur. Areas covered in the Christmas bird counts are generally those surroimding the loca- tion of local Audubon Society chapters. Bald eagles observed on the Christmas bird counts ranged from 256 in 1974 t
. Distribution and abundance of winter populations of bald eagles in Illinois. Bald eagle. Illinois Natural History Survey Biological Notes No. 129 Southeast Alaska. Northwest Interior Maine/ Nova Scotia I \\ Florida Breeding Area Represented by Bandings Fig. migraioi \ |)"l) Scrviii- 1986) Oilohii icmM-rics (IS. lisli . U ildlile most likely to occur. Areas covered in the Christmas bird counts are generally those surroimding the loca- tion of local Audubon Society chapters. Bald eagles observed on the Christmas bird counts ranged from 256 in 1974 to 767 in 1986 (Table 3). Differences in dates of counts, areas coveted, skills of observers, and weather conditions and the emphasis placed on counting eagles as opposed to other species create variability among the inventories (Table !5). Whereas counts for a single year vary widely, there are several instances when the changes between years are similar. Kxamiiiation of eagle numbers in Table 3 reveals that both the INHS and Fawks inventories show intreases from 1961 to 1962, decreases from 1962 through 1964, and increases fiom 1964 to 1965 and from 1977 tiirough 1979. Such similarities in trends suggest that patterns of changes in eagle nimi- bers in Illinois are real and demonstrate the impor- tance of more than one type of amnial count. Moving .3-year averages of the aiuuial winter. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Havera, Stephen P; Kruse, Glen W. [Champaign, Ill. ] : Illinois Natural History Survey
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