Barbara J. King

Friday Animal Blog

Zebra Finch Pairs with Matched Personalities Make Better Parents

January 21, 2011

Normally, my beat is mammals: primates, elephants, cetaceans and others who share humans’ taxonomic order. Doing research for a new book, though, I find myself reading more and more about the complex emotional lives of birds. This week I stumbled upon a new article by Wiebke Schuett, Sasha R.X. Dall, and Nick J. Royle in Animal Behaviour online, called Pairs of zebra finches with similar ‘personalities’ make better parents, that fits right in with this nascent focus.

I can come up with a quartet of reasons to blog about this article. Despite the title’s regrettable retreat into scare quotes, here are scientists unafraid to dive headlong into the arena of animal personality.

Schuett et al. define personality as “consistent, stable, individual differences in behavior across time and/or contexts.” They measure zebra finch personality in terms of the birds’ exploration of a novel environment and aggressive responses to a mirror. Additionally measured was the degree of consistency in behaviors by individuals.
Second, the findings are downright cool. It’s a somewhat dense paper both methodologically and statistically, but a pair of results strikes me as key:

* Male and female foster parents “that had been rated as both highly exploratory prior to pairing and highly aggressive after breeding fostered chicks that were in better condition than pairs of any other behavioural combination.” The point of the foster-parenting aspect is that genetic contributions to the next generation are controlled, with the difference-that-makes-a-difference more likely to be the behavioral input of the parents.

* When individuals within a pair were similarly consistent in their behavior—that is, similarly consistent or inconsistent—the offspring also did best.

The why behind these findings remains unclear, another reason to be intrigued by the paper. For a long time now, my primate work has focused on a process called co-regulation in social behavior: the considered and contingent back-and-forth between two primate social partners that allows them to solve problems or negotiate outcomes together (or sometimes that causes them to fail at problem-solving or negotiating).

Could the nature of the unfolding co-regulated sequences in like-behaving pairs versus others play a role here? The authors note that videos of the foster parents provisioning the offspring helped them not at all in understanding the benefit of similar personalities. They speculate that individuals with different personalities may favor different “response rules” when interacting with offspring, and that a reduction in sexual conflict is probably at the root of the results. If it were me, I’d look in future experiments at videotaped sequences for greater co-regulation in birds of like versus unlike personalities.

Finally, this paper reveals a gold mine of testable hypotheses. Birds aren’t birds aren’t birds. That is, what holds true for zebra finches may not hold true for other bird species, and further testing should show whether these results are widespread in pair-bonding birds.

Naturally, I am given to wondering about whether this study could be extended to those relatively few primate species who raise offspring via mated pairs. The marmosets and tamarins of South American are one good example; extended families of siblings surround the primary pair and everyone, not least the father, pitches in to carry and feed the newest crop of twins, heavyweights for the nursing mother. Would mothers and fathers of similar personalities do better in terms of infants’ condition than others?

I’ve always been a little uneasy, though, about the ethics of cross-fostering work. In any species with emotional bonds—birds or mammals-- is it really okay to snatch hatchlings or newborns and allot them to strangers in the name of science?


  1. January 22, 2011 8:58 AM EST
    very easy to observed the complex emotional lives of chickens. problem solving, child rearing, choosing to be gay or straignt, establishing "pecking order" communicating with chicken words understandable to humans, responding to human verbal commands, all this and more, plus a fresh egg from each hen every day, and they get to live happy chicken-normal lives! j
    - jeane
  2. January 22, 2011 9:14 AM EST
    Jeane, I wonder if growing up with chickens, then, kids would-- as much as growing up with dogs, say-- have an enhanced appreciation of and sensitivity to animal emotional complexities?
    - Barbara J. King

Selected Works

Why are animals so irresistible to us? Why do we live with and care so deeply about them? From the famous "art caves" of ice-age Europe, to the ancient villages where animals were first domesticated, to stories of apes, whales, dogs, and cats doing fascinating things today, King weaves together a scenario about the animal-human bond that encompasses our past, present and future.
Can scientists discover a prehistory of religion just as they have traced the evolution of technology, language, and art? What does compassion in chimpanzees, or burial patterns in our human ancestors and Neanderthals, tell us about the origins of religion? In Evolving God, named a Top Ten Religion Book for 2007 by the American Library Association, Barbara King explores these questions.
How do chimpanzees, bonobos, and gorillas-- the African apes -- communicate using body postures and gestures? Using her many years of experience studying these apes, Barbara King answers this question in a book that offers a new perspective on the evolution of language.