Bird moms manipulate birth order to protect sons

A newly hatched house finch (Carpodacus mexicanus) and its not-yet-hatched siblings.New research indicates that bird moms protect her sons from the blood-suckers by laying male eggs later than those containing their sturdier sisters during mite season. It’s a remarkable find. Nature never fails to amaze.

"Sons are more sensitive to the mites than daughters," said Alexander V. Badyaev of The University of Arizona in Tucson. "Mothers minimize sons' exposure to mites by laying male eggs later than female eggs. As a result, the males are in the nest fewer days."

Males that grew during mite season did more of their development in the egg before hatching. Their mothers accelerated their sons' growth, both in the egg and after they hatched. The male chicks that grow up during mite season end up just as big as ones from the mite-free time of the year.

Link: ScienceDaily
Image: © Alex Badyaev
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