Xcel Energy’s Fort St. Vrain eagles rode the big storm out last weekend. Despite an astonishing twelve or so inches of snow, Ma kept the eggs covered through most of it. Male and female eagles both incubate eggs, but females usually cover the nest at night and through bad weather. A female eagle’s larger body size and brood patch helps her stay still for longer periods of time and apply more heat to the eggs and young beneath her.
Unfortunately, falling ice broke one of the eggs at around 12:00 MT on March 15. Pa Jr. had just flown out of the nest in response to Ma’s vocalizations when a chunk of ice fell and cracked an egg. When Pa flew back in, he ate it. Neither he nor Ma stepped on the egg or ignored their clutch. They did the best they could under very difficult circumstances.
Why, when eagles spend so much time caring for eggs and young, do they eat broken eggs and (often) young that die? In the wild, nothing goes to waste. The broken egg could not be fixed and it provided a free source of valuable protein and calcium for Pa. Although eagles clearly have internal lives, instinct still governs a lot of their behavior. When the egg broke, it went from smooth round child to something that needed removal from the nest. Broken eggs won’t produce young or help incubation and brooding, but they will provide food for living eagles. Pa’s response was a fitting way to remove the broken egg while caring for the eggs that survived. Life isn’t always easy in the wild.
The Raptor Resource Project