Birds choose mates with same 'market value'

London, Oct 8 (ANI): Birds prefer to choose a mate who appears to be as attractive as themselves and has the same "market value", reveals a new study.

In the research, boffins found that female zebra finches never tried to play out of their league and happened to choose low-quality males rather than their superior competitors.

Marie-Jeanne Holveck and Katharina Riebel of Leiden University, the Netherlands, separated zebra finch chicks into either small groups of two to three chicks or larger groups of five to six chicks.

This was done because birds that grow up in big broods have fewer resources devoted to them and will be of a lower quality-weaker, weedier and poorer singers.

After the chicks had grown up, both low and high-quality females were placed in a cage where they could choose to listen to either a low or high-quality male song by pecking one of two red buttons.

Out of the 24 birds observed, every low-quality female chose the low-quality male song, and the high-quality females opted for males with high-quality songs.

The researchers then tested how birds of the same and different quality mated and found that in a cage together, birds of the same quality were much quicker to mate than mismatched birds.

When a low-quality female did mate with a high-quality partner, her eggs were larger-which, the authors said, was because the female knows she is doing better than she deserves, and will invest more nutrients into the eggs she lays.

Zebra finches mate seasonally, so they might not have time to wait around for Mr Perfect and mating out of their league could result in "divorce" if the male leaves for a higher-quality female.

The authors claimed that the finding echoes a popular perception that humans choose partners who they think are as attractive as themselves, or have the same "market value".

If perceived market value can affect mate choice in such diverse species, it could be a general phenomenon, said Holveck.

The study was published in the Proceedings of the Royal Society. (ANI)