Mating birds that are left to choose their own partner have healthier relationships, a recent study has revealed.
Zebra finches that shunned human attempts to matchmake them had a 37% higher reproductive success rate.
The study was done by researchers from the Max Planck Institute for Ornithology in Seewiesen, who looked at the reproductive success rates of the finches.
The team found that when zebra finches pair off with mates they chose, although they don’t lay more eggs, the eggs are more likely to be fertilised.
However, when the pairs were matched together by humans, the researchers observed a larger number of infertile eggs in forced pairs.
In addition to this, the pairs that resulted from free mate choice were more successful rearing their young from hatching to independence.
Malika Ihle, Bart Kempenaers and Wolfgang Forstmeier from the Max Planck Institute for Ornithology said: “An ideal mating partner may provide good genes for the offspring but may also enhance the number and quality of his offspring through being a good parent. However, within a given species there is often little agreement about who actually is the most attractive partner.
“Hence there are individual preferences that may reflect the need for compatibility of the partners’ behaviour or genes. To date it is largely unknown whether the suppression of such individualistic mate choice would result in fitness consequences.”
For the experiment, the researchers first allowed free mate choice amongst bachelor zebra finches, which meant they were able to exclude the birds that no one wanted to mate with.
After this, half of the pairs were split up, and forced to pair with the preferred partner of another bird.
After these two groups of birds were given time to create a stable bond, they then reared young in communal breeding aviaries.
The researchers found that eggs of forced pairs were more likely to be unfertilised, buried underneath the nesting material, or simply disappearing.
In addition to this, after hatching, the rate of offspring mortality was higher in the nests of forced pairs.
Malika Ihle, first author of the study said: “The majority of the young died within the first 48 hours.”
And interestingly, males trapped in a forced partnership were not as present and caring for its offspring during these critical days.
The main takeaway from the study was that the researchers believe, and indeed showed, that behavioural compatibility plays a crucial role in choice of mate.
Wolfgang Forstmeier said: “In socially monogamous animals, the matching of partners may be particularly important in order to motivate each other and to coordinate and share the various tasks.”
The team said that an individual’s opinion about their ideal partner should be taken seriously, because the compatibility of pair members can have important consequences, not only for the behaviour as a pair, but ultimately for their biological fitness.
Read more about the study here.