Couples with similar personalities make much better parents than those with different dispositions - at least in the world of zebra finches, researchers at the University of Exeter have revealed.
They found the birds expressing strong personality traits, such as aggressive behaviour or a willingness to explore did a much better job of raising young if they had a like-minded partner.
Where couples were markedly different in personality, chicks didn't fare as well - being less well fed and in poorer condition.
"In the case of zebra finches, to be good parents you need to be able to coordinate your behaviour so that while one parent is searching for food, the other is feeding the chick. It's a lot easier to co-ordinate your behaviour if you're similar in the way you go about things," Sasha Dall, an author of the study said.
Researchers focused in on the 'personalities' of a group of zebra finches. They were able to establish that some showed consistent patterns of behaviour, normally either reflected in different levels of aggressiveness or willingness to explore.
Often the traits were combined, but some finches didn't demonstrate them at all.
Then couples were artificially paired together - with a selection of couples who were like-minded and some who had no common traits. When mated, eggs were swapped between nests in order to distinguish the advantages of genetic, as opposed to the behavioral compatibility of parents.
Experts then studied the animals while they were feeding their chicks, and monitored the progress of hatchlings to see which couples were doing the best job as parents.
"We found that if birds were highly exploratory and their partners shared that trait, their offspring were in really good condition. It was the same for highly aggressive birds. If only one parent showed the trait, the chicks fared less well," Nick Royle, another author on the study, said.
The finding was published in the journal Animal Behaviour.