Incubating begins as the female lays the first egg and lasts about 35 days. The clutch of one to three eggs is completed within three to six days. Both parents share in the task of incubating.
Both male and female eagles form a brood patch--a bare spot on their abdomen where they can press their skin directly against the eggs to keep them warm. The female's brood patch is bigger and more feather-free than the male's because she incubates the eggs more often. While one eagle sits on the nest, the other is hunting for food or perching nearby to protect the nest.
Eggs must be kept warm, shaded from harsh sunlight and protected from predators. During incubation, an adult will poke around the nest with its bill arranging nest materials and also standing to turn the eggs – it may roll egg(s) carefully with balled feet or its bill, then rock side to side as it settles back over the eggs.