. Distribution and abundance of winter populations of bald eagles in Illinois. Bald eagle. Fig. number of bald eagles tountecl per inventory at areas within the Central Illinois River Region, 1972-1986. Fig. number of bald eagles counted per Lower Illinois River Region. 1972-1986. 0 to ^ of tlie total eagles observed, and the overall proportion of immatiires was ^ for all inven- tories. The mean number of eagles inventoried per cen- sus flight is illustrated in Figure 24. ,\reas with the most use by bald eagles intluded Chautauqua National Wildlife Refuge (F
. Distribution and abundance of winter populations of bald eagles in Illinois. Bald eagle. Fig. number of bald eagles tountecl per inventory at areas within the Central Illinois River Region, 1972-1986. Fig. number of bald eagles counted per Lower Illinois River Region. 1972-1986. 0 to ^ of tlie total eagles observed, and the overall proportion of immatiires was ^ for all inven- tories. The mean number of eagles inventoried per cen- sus flight is illustrated in Figure 24. ,\reas with the most use by bald eagles intluded Chautauqua National Wildlife Refuge (Fig. 25), Crane Lake, Clear Lake, Cuba Island, and Jack Lake (Appendix). .\11 of these areas are privately owned except the 4,500-acre (1,822-ha) Chautauqua Refuge. al in late September and early October and spring dejiaiture by eailv \pv\\ were similar to those in the Cential Illinois Ri\er Region. Eagles arri\ed in the Lowei Illinois Ri\er Region approximately 1 week earlier than in the Cential Illinois River Region in 2 of the 15 years inventoried. Peak population counts have occurred from 2 De- cember until 18 March; the latter is also the date of the highest 1-day count of .345. The proportion of immatures seen on indixidual censuses ranged from. 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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