Cameras set up on a bald eagle nest near Vian in the Sequoyah National Wildlife Refuge captured a heartbreaking incident this week.
A bald eagle had laid two eggs on the nest last month. As the eggs began to hatch, something unexpected happened. A male bald eagle picked up one of the eggs and dropped it out of the nest. The female then abandoned the nest and the remaining egg.
Here's what Sutton Center Director of Conservation Dr. Steve Sherrod wrote about what happened:
"Yesterday, March 18, was one of perplexing behavior by the eagles nesting at SNWR. Accounts captured on the cameras and witnessed by video observers show visible, independent movement in one or both eggs, with an apparent yellow blob beyond the top of one egg in the nest. The female that was incubating became upset, was vocalizing, left the nest, and returned with the male. At least one of the eggs appeared misshapen at that time, as if either hatching or partially broken. One of the adults then appears to pick up the misshapen egg in its beak and drop the egg over the edge of the nest. Incubation of the single egg left in the nest then continued, but today, March 19, the remaining egg has appeared unattended for over 6 hours at the time of this writing and will likely no longer be viable.
I have studied and maintained raptors for much of my life and have either hatched in captivity or have overseen captive hatching of nearly 300 bald eagle eggs and many more hundreds of peregrine, gyrfalcon, and prairie falcon eggs. Unfortunately, I cannot say with absolute confidence just exactly what happened yesterday with this bald eagle pair, but I have a reasonable idea. It is likely that at least one if not both 2014-2015 Sequoyah bald eagle eggs were hatching with almost completely developed chicks in the process of turning or rotating within and breaking out of the shell(s). Both captive breeding and wild breeding peregrine falcon adults have been observed, in rare cases, to pick at hatching eggs with their beaks, sometimes appearing to “assist” the young out of the egg shells. Usually, no “help” for the hatching chicks is exhibited or needed. On very rare occasions, adult falcons have been observed to continue picking at the cracked shells and actually into the hatching chicks, so that the latter are either killed or eaten by the adult. Older (about 2 week) peregrine chicks have been consumed by adult falcons in very rare instances as captured by nest cameras.
During the hatching process the chicks often, although not always, vocalize. A chick that is having trouble completing the rotational turn during hatching or in freeing itself from the shell halves can vocally protest rigorously. Also, a hatching chick that is sickly can remain inside, weak, and silently pass, or can protest vocally while continuing to struggle. This is especially true when the chick has a yolk sac infection, often resulting from bacteria invaded through pores in the egg shell. Such infections are usually fatal for the chick. Adults might react to the complaining chick by trying to brood it, feed it, or by eventually killing it, sometimes feeding the deceased chick to the other chicks in the nest or sometimes discarding the individual out of the nest. Such behavior might function to actually spread the infection or might serve as conservation of energy for the family group. If the second Sequoyah bald eagle egg ends up deserted, it could possibly be infected as well. We do know that when eggs are warm from incubation, and an adult must get off the eggs to eat or otherwise departs during a rain storm, the cold rain on top of dirty, but warm eggs, facilitates invasion by bacteria on the shell. (For that reason, we always clean eggs in captivity with a warmer solution than the temperature of the incubated egg). Without tests for disease in the deceased eggs/chicks, or without ability to hear chick vocalizations we can only speculate about what might have happened in this instance at Sequoyah, but the preceding scenario is likely."