True Love Matters. Learn Why With Zebra Finches

We can’t really pinpoint what love is, but overwhelmingly love seems to be the main ingredient for a long-lasting, committed and affectionate relationship.

If this holds true for human society, why wouldn’t it apply to birds as well? A team of researchers from the Max Planck Institute for Ornithology, Germany found that a different pattern of attraction takes precedence over the ‘good genes’ choice when it comes to zebra finches.

As it happens, zebra finches choose partners with which they form monogamous couples, start zebra finches families and share responsibilities with view to attending to their offspring and raising them.

And while a certain number of females pertaining to other bird species are attracted to the males that perform the best mating dance or the best wooing routine or have the brightest plumage and longest tails, females of the zebra finches are certainly more picky.

Researchers couldn’t pinpoint what exactly factors in when talking about attraction between a female and a male zebra finch. However, it went beyond the good genes approach when it came to mating.

Conducting their research on a captive population of 160 zebra finches, the research team separated two groups of zebra finches, each comprising 20 males, respectively 20 females. The birds were housed in common aviaries where the non-breeding season saw the free forming of 20 pairs of zebra finches. Everything must have looked rosy in paradise as the females had chosen the partners they wanted.

However, half of them were soon after torn from their happy couples and force-paired with other males. To make sure that they get a fair chance to breeding, the researchers assigned the unlucky female zebra finches male partners that had been previously chosen by other females.

The breeding-season came and all of the pairs thus formed were nested in individual cages to force pair-bonding. Three of these pairs, as well as three zebra finches pairs from the free-formed pairs were brought back to the communal aviaries where they bred and brought approximately three broods to the world.  

The experiment didn’t end here. Of the 20 pairs formed before the first breeding season, both force-paired and free-paired, another two thirds were torn from their couples. They were brought back to the aviary where they had to find a new partner. Half of them draw the lucky ticket when they remained in their newly free-paired couple, while another half experienced force pairing once more. One third of the birds were left in their already formed pairs from the first breeding season.

What the researchers observed is that choosing their partners freely and not being forced into a pair yielded better results regarding the offspring. Zebra finches who had freely chosen their male partner started families where the offspring a 37 percent higher chance of surviving. Not only were the zebra finches chicks stemming from these pairs better protected, but they benefitted more from the male’s presence around the nest.

In the other nests, the disgruntled zebra finches females had laid less eggs. They also lost a higher number of eggs and three times more eggs were found unfertilized. Whatever chicks did hatch in the nests of the force-paired zebra finches couples had a higher rate of mortality, particularly in the first 48 hours of life as the male left the nest more often during this period.

As such, it looks like for the zebra finches, choosing a partner to their own liking bodes well for the future of the species. When forced into pairing, the females reacted in a fussy manner. They didn’t wish to synchronize their behavior pattern and showed it by flying in opposite directions than the males.

When choosing a partner to their liking, they were far more receptive and more inclined to copulate far more often. Talking about monogamy: in forced zebra finches pairs the male strayed from the nest and looked for other females to woo and mate with.

The results of the study are published in the PLOS One journal.

Photo Credits: Flickr