One of the greatest pleasures in science is discovering that you were wrong. This project was one of those rare occasions where the data gently nudged us away from our predictions and toward a far more interesting story.
Our laboratory, the Animal Cognition Research Group, studies how animals gather and use information when making decisions. A central question in behavioural ecology and comparative cognition is how individuals balance their own experiences with information gained from others. Social learning can be powerful, allowing animals to avoid costly trial-and-error learning. Yet individuals often differ in whether they copy others or rely on their own knowledge.
For more than a decade, our group has used zebra finches, small, highly social songbirds from the Australian Outback, as a model system to study these questions through the lens of nest building. Nest building is a useful behaviour to study because it requires hundreds of decisions, from selecting materials to determining where and how they are used, and those decisions directly influence reproductive success.
In previous work, we found that zebra finches do not simply copy one another. Instead, their use of social information depends on context. That naturally led us to ask a deceptively simple question: could stable individual preferences explain why some birds copy while others do not?
The question itself has surprisingly deep roots.
Nearly a century ago, naturalist power couple Henry and Felicia Williams described birds in their Connecticut garden repeatedly selecting coloured nest materials. They intentionally left out dyed wool for the birds to collect and, in their delightful 1939 book The Private Lives of Birds, wondered whether individual birds might have favourite colours. At the time, there was no straightforward way to determine whether these apparent preferences reflected genuine individual differences or simple chance. If you ever stumble across a copy of this wonderfully observant and witty book, I highly recommend it.
Science often celebrates entirely new ideas, but sometimes progress comes from revisiting wonderful old observations with better tools.
Almost 100 years later, we had the opportunity to test the Williams' idea experimentally. The project was led by our postdoctoral researcher, Dr. Ben Whittaker, and brought together a wonderful team at different career stages. One of the co-authors, Henry Swartwood García, joined our laboratory as a Mitacs Globalink Research Intern from the Universidad de las Américas Puebla in Mexico, spending a summer in Edmonton contributing to the project. Simran Gill, then an undergraduate researcher at the University of Alberta, and Julia Self, an MSc student in the laboratory, also played key roles. One of my favourite aspects of science is watching people at different stages of their careers collaborate to answer questions that none of us could have answered alone.
The first challenge was determining whether colour preferences were actually consistent through time. If a bird preferred cerulean blue one week and neon pink the next, colour preference would be little more than random noise. Instead, we found the opposite. Individual zebra finches displayed remarkably repeatable preferences for coloured nest-building materials. Some birds consistently preferred one colour, while others consistently preferred another. Even female zebra finches, which rarely carry nesting material to the nest themselves, showed repeatable colour preferences. Although females typically rearrange materials deposited by males rather than collect them, they too appear to have consistent preferences for the materials that make up their future home.
That finding alone was exciting because repeatability is one of the hallmarks of meaningful individual differences.
But the real surprise came when we combined these data with earlier social learning experiments from our laboratory.
We originally expected that birds with strong preferences might still copy the majority if enough social information accumulated. Instead, we found that an individual's initial preference was a remarkably good predictor of how it responded to social information. Birds with weaker preferences were more likely to adjust their behaviour after observing others, whereas birds with stronger preferences tended to maintain their original choices.
The finding changes how we think about social learning. Rather than viewing animals as simply copying or ignoring others, our results suggest that social information is filtered through each individual's existing preferences. In other words, the same social information can lead to different decisions depending on who receives it.
The project also reflects our laboratory's commitment to open science. As with all of our empirical papers over the past several years, we have made both the raw data and annotated R code publicly available alongside the publication. We hope this transparency makes our work easier to reproduce, build upon, and integrate into future meta-analyses, another of my favourite scientific odysseys.
Perhaps my favourite aspect of this study is that it demonstrates the value of curiosity. It began with two naturalists watching birds in their backyard nearly a century ago, and ended with a modern experiment testing the same question using contemporary behavioural methods. It was equally delightful to discuss the Williams' domestic adventures with Ben while planning this project, proving that reading old natural history books can still inspire new science.
I like to think Henry and Felicia Williams would have enjoyed this result. Nearly a century after they scattered coloured wool across their Connecticut garden and wondered whether birds had favourite colours, we were finally able to test their idea. They were right to ask the question. As it turns out, individual preferences do matter, and they help shape how animals use the social world around them.
Perhaps it is the nostalgia of growing up in the woods on a lake in Connecticut that made me feel such a connection to the Williams' pursuit. I have always been fascinated by nests because they are among the few animal artefacts we can hold in our hands: physical records of the countless decisions birds make while gathering information about their world. Better yet, they are available to all of us. Whether discovered in a country garden like the Williams' or high in the trees of an urban neighbourhood like Edmonton, where magpie nests are impossible to miss once you start looking, nests invite anyone, not just scientists, to stop, look up, and wonder how they came to be.
Please see our original paper: https://link.springer.com/article/10.3758/s13420-026-00723-5
Williams, H. S. (1939). The private lives of birds. Robert M. McBride & Company
Video of a zebra finch male building colorful nests in our laboratory: https://youtu.be/6gDUpzXyI-8
Visit our website for more information about our work or if you would like to join our team: https://sites.psych.ualberta.ca/animal-cognition-ualberta/
For more popsci writing from our team check out these articles in The Conversation: https://theconversation.com/birds-nests-express-their-unique-style-and-past-experiences-216799 and https://theconversation.com/strong-opinions-matter-why-some-birds-refuse-to-follow-the-flock-275905