London: Birds learn new foraging techniques by observing others in their social network, a new study led by Oxford researchers has found.
This 'copycat' behaviour can sustain foraging 'traditions' that last years, said researchers who studied how innovations spread and persist in wild great tits (Parus major).
The study involved experiments with eight local populations of great tits in Wytham Woods, Oxfordshire (UK).
In five of the populations two male birds were trained to slide a puzzle box door either to the left or to the right. In three control groups two males were captured but not trained.
The birds were then released back into their original populations to act as 'innovators', together with puzzle boxes that revealed a tasty mealworm reward when opened from either side.
Electronic tags on the birds recorded how the two box-opening methods spread in each of the local populations through social network links.
Despite both methods working equally well, the team, led by Oxford University researchers, found that each experimental population strongly favoured the puzzle-solving solution that had been introduced by the trained birds.
The preference for this arbitrary solution increased over time, forming a stable tradition. In the control populations, by contrast, it took much longer for birds to learn to solve the puzzle box.
When the experiments were repeated a year later each population still favoured their own 'traditional' method even though only 40 per cent of each population of 75-100 birds were survivors from the previous year.
The researchers were able to show that, even when birds discovered both ways of opening the puzzle-box, they were much more likely to use the behaviour that was dominant in their local population; in other words, they conformed to the behaviour in their local population.
The research, reported in the journal Nature, is the first experimental demonstration of the spread of culture, and the operation of conformist learning in a wild non-primate.
"We were able to experimentally demonstrate that sustained foraging traditions can occur in wild great tits," said report author Dr Lucy Aplin of Oxford University's Department of Zoology.
"This appears to have been partly due to a process of conformity - the birds were preferentially copying the majority behaviour," Aplin said.