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Siblings are special. Be they protector or tormentor, friend or foe, the relationship between siblings is like no other. They witness each other’s childhoods — sharing parents, history, secrets and advice.

Even among some bird species, siblings can be powerful role models — eclipsing even their parents’ influence — according to a study from the ɫ��ɫ, and the Max Planck Institute of Animal Behavior.

published in the journal PLOS Biology, is the first to examine social learning strategies in juveniles in the wild where the species has some, but not extensive, parental care.

“Much of our knowledge about social learning in juveniles stems from species with extended periods of parental care, including humans,” said lead author Sonja Wild, who was a postdoctoral research associate with ɫ��ɫ and the Max Planck Institute when the study was conducted. “A lot of learning occurs from parents because offspring and parents spend so much time together. But what happens with knowledge transfer when parental care is limited?” 

Learning life skills

Using the songbird Parus major, commonly known as the great tit, as a model species, the researchers found that siblings and other adults can be key sources for learning life skills when parents are rarely present. This alternative pathway helps explain behavioral similarities in families with limited parental input. 

“When they leave the nest, they know nothing,” Wild said of the species. “They can’t feed themselves or find shelter. All they have is about 10 days of parental care to figure everything out. The offspring would like to extend that time. They follow their parents around and keep begging, but the parents are exhausted and start pulling back. So the selection pressures are really strong for offspring to quickly figure out how to find food themselves.”

Puzzling behavior

To understand the social learning strategies of the young birds, the authors presented 51 breeding pairs and their 229 newly fledged offspring with feeding puzzles for 10 weeks. The birds could solve the puzzles by sliding a door to the left or right to reach a tray of mealworms. 

“Fully automated puzzle boxes allowed us to collect high-resolution data on hundreds of microchipped birds,” Wild said. “This produced tens of thousands of solves that helped disentangle the pathways of learning and the decision-making strategies the juveniles employed during their transition to independence.”

After tracking the birds’ solving behavior for 10 weeks, they found the birds were more likely to learn to solve the puzzle if their parents were skilled at solving it. However, the young birds’ solution strategies were much more strongly influenced by how their siblings and non-parent adults solved the puzzle. 

Of the first learners of each sibling group, nearly 75% learned from adults who were not their parents, while about 25% learned from their parents. Of the subsequent learners in each group, about 94% learned to solve the puzzle from their siblings. 

Resilience and conservation

Understanding animal behavior can be valuable for biodiversity and wildlife conservation. 

“The more diverse animal cultures are, the more resilient populations are to extinction and able to deal with environmental fluctuations,” Wild said. “Such species are less vulnerable because they have many different role models from which to get cultural and socially learned information.”

The study’s additional co-authors include Gustavo Alarcón-Nieto from the Max Planck Institute and Lucy Aplin from the Australian National University, Max Planck Institute and University of Zurich.

The study was funded by German Research Foundation and a Max Planck Society Group Leader Fellowship.