Finch Moms Manipulate Birth Order to Protect Sons

Credit: Copyright 2005 Alex Badyaev
A mated pair of House Finches (Carpodacus mexicanus) and the mites that infest their nests.

Bird Moms Manipulate Birth Order to Protect Sons
Hormonal changes affect egg laying and development


September 19, 2006

According to a new study by scientists at the University of Arizona, female house finches are able to change their hormonal makeup to ensure male birds hatch later, grow faster and spend less time in the nest than their sisters. The strategy is nature's way of protecting vulnerable male hatchlings that appear to be more sensitive to nest-marauding mites than their female siblings are.

Once breeding female finches are exposed to mites, their bodies make hormonal changes that affect the order of egg laying and accelerate development of their sons while they're still in the egg. The scientists say that helps make sure male chicks are exposed to mites for a shorter period and allows both the sons and daughters to survive long enough to leave the nest.
And not to worry, the researchers say, the male chicks that grow up during mite season end up just as big as ones from the mite-free time of the year.

The work, which is scheduled to be published in the early online edition of the Proceedings of the National Academy of Sciences the week of Sept. 18, was funded by the David and Lucile Packard Foundation, the National Science Foundation and the Silliman Memorial Research Awards.
-NSF-

Courtesy of the National Science Foundation

What can I say? Birds never fail to amaze. D. B.