Male great tits have divergent personalities, the competitive jock and the brainy problem solver, and those personalities can influence their ability to compete for food.
Credit: Roy and Marie Battell
Not often do you find a good-looking jock who has nerd-level computer smarts. Turns out the same goes in the wild, but the divergent personalities among wild male animals do not seem to hurt their ability to obtain food, new research suggests.
"We have seen a lot of variation in ability to compete in individuals," study researcher Ella Cole, of Oxford University, told LiveScience. "There seems to be a trade-off between ability to compete and cognitive ability. If you are bad at competing, you might be good at finding resources in other ways."
The researchers studied members of a species of perching bird, great tits, in the lab and in the wild to see how these personality tests translate into behaviors in nature. Individuals with bold and aggressive personalities seemed to be better adapted to the here and now, because they can outcompete against other individuals; still, in the long term, this competitive personality is costly in energy and health. And so what the more shy personalities lack in competitive abilities, they make up in staying power. [Read: Animals Have Personalities, Too]
The researchers first brought some of the wild birds into the lab to assess their personalities. They placed the birds in a room containing fake trees and watched how far they roamed. Wide roamers got higher "exploration behavior" scores than did close-to-home birds.
Then the researchers took these birds to task: The tits had to solve a problem, which included retrieving worms from a platform by moving a lever. Only 44 percent of the birds were able to solve the problem. Their ability and how quickly they solved it provided the birds' "problem solving" score.
These behaviors are personality traits; they stick with the birds for their entire lives.
Then in the wild, the researchers replaced the tits' normal feeders with ones containing only one feeding hole, so the birds would need to compete for eating time.
They found that the birds that had scored highest on "exploration behavior" — those with the bold, outgoing personalities — were the best at competing for time at the feeder. The birds that scored high on the "problem solving" scale spent less time competing over food.
"There are indeed consequences of these behaviors, but … the competitive ability of an individual is not a measure of its quality, but part of a behavioral strategy," Kees van Oers, a researcher at the Netherlands Institute of Ecology who wasn't involved in the study, told LiveScience in an email. "This shows that being the most successful at a feeder does not imply being the best overall."
The study didn't determine which came first, the behavior or the personality. It could be that the problem solvers don't need to compete as much over the feeders because they can find food elsewhere, and the costs of competition can be high.
While researchers don't think these different personalities affect the birds' overall ability to survive, they could have an impact on reproduction, since mating is based on dominance, which is dependent on a competitive nature. The researchers plan further studies on this subject. [Top 10 Swingers of the Animal Kingdom]
Erik Matthysen, a researcher at the University of Antwerp in Belgium who wasn't involved in the study, observed that it was a "valuable step toward explaining why some individuals are more successful than others in natural populations."
The study was published today (Sept 20) in the journal Proceedings of the Royal Society B: Biological Sciences.