In a magnificently thought out piece of research, biologists have discovered that forced coupling among birds may be a bad thing, with zebra finches, for example, far happier to choose a mate.
By setting up a speed-dating system, the study looked at birds that chose a mate, in comparison to those arbitrarily paired off, to see how compatible they were.
What transpired was a vast difference in the survival of offspring, with 37pc more chicks surviving from parents that had chosen a mate.
The nests of non-chosen pairs had almost three times as many unfertilised eggs as the chosen ones, a greater number of eggs were either buried or lost, and markedly more chicks died after hatching.
Most deaths occurred within the chicks’ first 48 hours, a critical period for parental care during which non-chosen fathers were markedly less diligent in their nest-care duties.
A clever, twisted study
The way the researchers conducted the test was quite simple, and a bit twisted. They got 160 zebra finches and divided them by gender.
Then they put them into batches of 20 females and 20 males, to find a mate. One group paired off, researchers leaving them to it.
For the other group, though, they stepped in and paired together birds that had not chosen each other.
Science isn’t kind.
Surprisingly, or perhaps unsurprisingly, the non-chosen couples weren’t as affectionate, copulated less frequently and were, basically, not great parents.
Birds mating: none of your business
Overall the authors found that birds choose their partners for personal reasons, to personal taste, and we can’t really work out what it is they look for.
“The percentage of nestlings that died before reaching independence was twice as high if chicks were raised by assigned pairs,” said Malika Ihle, the lead author of the study published in PLOS.
“If a chick hatched in such a nest, it only had a 50pc chance of surviving,” said Malika, according to Science.
“To me, love is a peculiar attraction toward a specific individual that is not necessarily shared by other choosing individuals.
“It seems that the chosen pairs, those ‘love marriages’, invested more into reproduction, were more committed, more faithful, and more motivated to raise their family.”
This will no doubt lead to further research into animals kept in captivity, and could lead to a greater understanding of why some breeds simply don’t reproduce enough in these circumstances.
Main image via Shutterstock