Speed-dating experiment proves birds fall in love too

SEEWIESEN, Germany, Sept. 15 (UPI) -- Birds form relationships not unlike humans do: choosing a partner not based purely on objective aesthetic and performance standards, but on attraction and compatibility.

According to a new speed-dating study (involving zebra finches, not people), mates appeared to choose each other for reasons invisible to the outside observer. In other words, attraction is idiosyncratic -- not easily predicted by an algorithm.

But why? The speed-dating experiment suggests this manner of pairing off (or "falling in love," as humans might call it), makes birds happier and more likely to successfully reproduce.

In the experiment, some birds were allowed to freely choose their mate, while others were forced into cohabitation (an "arranged marriage"). When left to their isolated aviaries to mate, freely chosen mates copulated more frequently, produced more eggs and had a higher survival rate among their newborns.

While males tended to give the same amount of attention to their mates, forced or chosen, females were less likely to receive their advances if the pairing was forced.

The new study, published in the journal PLOS ONE, makes it clear that zebra finches form pairs based on behavioral compatibility, not genetic. The research also proves that freely chosen pairs are reproductively more successful.

But, as the researchers from the Max Planck Institute for Ornithology acknowledged, they can't be sure whether reproductive success and more attentive parenting is the result of a motivation to cooperate or compatibility intrinsic to proper pairing of personalities.

"The mechanisms behind such behavioral compatibility," researchers wrote, "in terms of willingness or ability to cooperate with certain individuals and in terms of coordination between partners need further study, in particular in the context of offspring provisioning."