Does sex-biased hatching order in bald eagles vary with food resources?

This is the authors' abstract. We don't add key points for this paper.

:In birds that exhibit sexual size dimorphism, hatching asynchrony, and siblicide, the probability of nestling mortality and the cost of rearing young may vary with different combinations of sex and hatching sequence. When food abundance varies spatially and temporally, parents may maximize their fitness by manipulating their primary sex ratio. We examined the sex and hatching order of nestling bald eagles (Haliaeetus leucocephalus) over 17 years on one lake and 5 years on another. The lakes are approximately the same size, but differ dramatically in eagle density and prey abundance. In years when the number of eaglets fledged was high (suggesting higher food abundance), there was a significant bias in the first-hatched chick toward the larger sex (females), and broods with a first-hatched male and a second-hatched female (MF broods) were under-represented. In years with lower productivity, and on the lake with lower food abundance, there was a male-bias in the population sex ratio of nestlings and the first-hatched egg. Variation in sex ratio and hatching order may relate to the probability of siblicide associated with MF broods, or the differential cost of raising the sexes.