Some Observations on the Behavior of Captive Bald Eagles Before and During Incubation
Preincubation and incubation behavior were studied in two pairs of captive Bald Eagles. During the preincubation period, perching together, nest building and repairs, copulation, mutual billing and stroking, courtship feeding, and pseudoincubation were observed and described, and the frequency was quantitated. During incubation, activities concerned with nest maintenance, nest relief, and feeding were observed and quantitated. The time the Bald Eagles left the eggs exposed during incubation varied significantly with changes in the ambient temperature and wind velocity. A significant correlation was found between the average time the eggs were left exposed (min/h) and the wind chill index, with eggs being exposed least when the cooling power of the air was the greatest.