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Aerial inventory of the North Fork began in November of the second field season. • Date Adults 11/01/79 0 11/14/79 1 (helicopter) 11/29/79 0 12/19/79 0 02/26/80 0 On the helicopter flight of November 14. several side creeks were examined. This route is detailed on the accompanying flight map, and was flown only once because of the low number of eagles seen and the risks involved. Ground surveys were conducted from Delta to Paonia Reservoir along Highways 92 and 135 on January 10 and April 17, 1979 with numerous stops to check the river with binoculars. No birds were seen on either day; however. only a small section of the river can be surveyed ef- fectively from the road. This route was driven again on December 12, 1979 with similar results. It is interesting to note that only adult birds were seen on the North Fork in the first season. This may be explained by: (1) the type and abundance of prey available for the wintering bald eagle (the relatively less experienced immature birds may not be able to use the available food), and (2) by the greater visibility of adult birds. Flights in • fixed-wing aircraft which do not scare birds off their perches, pro- bably give incomplete counts of young birds. Dave Kenvin, District Wildlife Manager (DWM) in Paonia, provided some historical information on bald eagle use in the North Fork. Nis sight- ings have been marked on the topographic maps in orange. In talking with him, the general trend in past years has been for eagles to be dispersed in side drainages in the Fall, and then to move down to the open water of the rivers as these creeks freeze. The small sample of eagle sightings in the second field season does little to either sup- port or refute this. A local resident, Marlene Christopher. reported that over the last several years she has observed bald eagles along Anthracite Creek. the North Fork and at Paonia Reservoir in January and February. EAGLE USE Most observations on this stretch of river were of birds perched in large cottonwoods. No hunting by eagles was observed along the North Fork, but since most surveys were aerial, there were no opportunities for long-term observations of individual birds. Use of the North Fork by bald eagles peaked in late January-early February of 1979 (see Figure 12). Throughout the winter, the eagles perched along the river, with few spots appearing to be favored, perhaps indicating that birds perched near carcasses or other transitory food sources. No night • roosts were located. Use of the North Fork by bald eagles in the winter of 1979-80 appeared to be much lower than that previously seen (see Figure 13).