In general, the panel believed that the egg’s viability couldn’t be determined from the video, although two of them commented that a darker patch in the draining egg fluid could have been an embryo. At 19 days old, an embryo would still have been quite small and not especially easy to see given the circumstances. Since we couldn’t come to a definite conclusion, our answer is “No” – we don’t know whether the egg was viable or not. We have some information about embryonic developmental stages here: https://raptorresource.blogspot.com/2017/03/whats-inside-those-bald-eagle-eggs.html
So why did the egg break? Female eagles lay down calcium in their shell gland/uterus, and their large eggs take a lot of calcium. Was she not able to lay down enough calcium to protect her egg from breaking, and if so, why? She may not have had enough calcium available during that stage of egg formation, or something else could be going on with her reproductive system. One member of the panel asked about her age. Female bald eagles and peregrine falcons can experience reduced fertility as they age. They might lay fewer eggs, strangely colored eggs, oddly shaped eggs, ‘smooshy’ eggs, thinly-shelled eggs, or infertile eggs that never hatch. It’s too early to know whether that’s the case, but we will be watching to see if any of those things happen moving forward.
Was she poisoned again? We saw no sign that she was poisoned this year, and the poison from two years ago would not affect her shell deposition now.
Is Mrs. North likely to produce more eggs? The answers were mixed. If she does, it should happen around March 30, or about 14 days after she lost the first one. Other birds of prey, including gyrfalcons and barn owls, take 14 days to recycle after losing a clutch. I really went back and forth about this (19 days is a long time to incubate an egg!) but the answer gave me some hope, especially given that Mr. and Mrs. North are still copulating. We’re crossing our talons, hoping for the best, and keeping a very sharp eye on Mrs. North!
