An unexpected discovery has been made by ornithologists in Ohio.

Female birds seem to invest extra energy in giving to poor-quality genes bearer offspring a reasonable start. This was observed at least in house finches ( Carpodacus maximus ).

Female's organism can deposit different levels of health-promoting nutrients in their eggs, conditioned by social and environmental factors.

Previous researches in birds from the order Passeriformes indicated that females were more likely to invest in the eggs carrying the genes of high-quality males.

Kristen Navara, from Ohio State University in Columbus, made her research on house finches.

In this species, the sign of health and good gene quality is represented in males by the redness of the feathers.

Red feathers mean the male has enough energy to invest it in high quality plumage.

But the measurements showed another story.

Eggs from matings with drab feathered males were 2.5 times richer in yolk antioxidants, including vitamin E and three carotenoids, which color the plumage red.

"That shows the house finches have a different strategy," Navara says.

House finches have a lifespan of 2-3 years, so it extends over only 1 or 2 mating seasons.

It makes sense for them to increase the health of eggs fertilized by low-quality, "ugly" fathers in order to compensate for their deficiencies and improve their own reproductive exit.

"They're trying to make the most of the reproductive event," she says.