Re: Sat., March 17, 2018 - Eaglet moving in the nest; no parents.

Posted by NewMexiKen on Mar 18, 2018; 10:07am
URL: http://bald-eagles-of-broward-county-florida.17.s1.nabble.com/Sat-March-17-2018-Eaglet-moving-in-the-nest-no-parents-tp7574892p7574893.html

Beautiful photos! Also a good question about the eaglet's gender--

The supposition that "P Piney 19" is a female eaglet is based upon the probability (3:1 or even as high as 9 out of 10) that it was the first-hatched of the brood. If, as we believe, there was a second eaglet which subsequently disappeared it could have been another female, as two females can be very aggressive towards one another. If she had been the second-hatched, then the first may well have been a male which would be at a great disadvantage because the female quickly outgrows and out-competes him. We cannot be certain but ground observations pretty well pinpointed the laying of the first egg and the hatching date, which was 34 days later. On average, Bald Eagle eggs take 35 days to hatch.  See this article:

"By examining the effects of sex, growth, and hatching asynchrony on the relative size of sibling bald eagles, I show that the probability of brood reduction is not equal among broods of different sex composition. The hatching sequence of male first and female second was predicted to have the greatest chance of experiencing nestling mortality. This type of brood is rare in bald eagles because there is a sex-dependent hatching sequence whereby the first egg in mixed-sex clutches is predominantly female (93%)"

Influence of Sibling Competition on Nestling Sex Ratios of Sexually Dimorphic Birds

https://www.journals.uchicago.edu/doi/abs/10.1086/284498