Re: APRIL 10: One eaglet seen in nest-- other has been killed

Posted by NewMexiKen on Apr 12, 2016; 9:58am
URL: http://bald-eagles-of-broward-county-florida.17.s1.nabble.com/APRIL-10-One-eaglet-seen-in-nest-watch-for-second-tp7574461p7574464.html

Yes, Kathy it is very sad to learn that the older and more aggressive eaglet killed the younger one. I feared it was being cowed into laying low or even already injured by the older one when I posted my message. Siblicide is one of the eagles' keys to success, as it gives the surviving eaglet a much better chance of becoming an adult.

As you may know, the first eaglet is more likely to be a female than a male, and she is larger than the male at all ages.  The second is more likely a male, so there is a 1:1 sex balance. The first-hatched, if a female, is more likely to kill a second female, perhaps because it eliminates a competitor while still small and weak.  A female and male sequence is the most successful combination for survival, maybe because the male learns its place in the hierarchy and does not challenge the female. This also assures a balance between the number of males and females as adults. If the first-hatched is a male the entire brood has less chance of surviving than if the first is a female.

Since south Florida eagles developed an instinct to breed much earlier than those up north, there were inherent advantages-- less heat stress on the eaglets and better prey availability when they are growing fastest in February and March. Let's hope that Pride and Jewel can provide for the single eaglet and see her fledge successfully sometime in late summer.

If you have a higher-resolution photo I would like to see it.