Why Australian behavioural biologist Lucy Aplin is fascinated by birds and how she wants to clarify a fundamental question of life with her research project on sulphur-crested cockatoos in Sydney.

Lucy Aplin likes birds. They are her life’s programme. Little Lucy often accompanied her father, a zoologist, on research excursions to the Australian outback. He was interested in reptiles, she in birds. «When I was five, I got my first pair of binoculars and from then on there was nothing else for me but birds,» she tells us with a laugh. Today, the charming Australian is a successful behavioural biologist working on the cultural evolution of birds. She currently concentrates on a large research project that focuses on the learning and adaptability of sulphur-crested cockatoos to urban habitats. As a result, Lucy Aplin works at the research site in Sydney in the summer and at the University of Zurich in the winter.

Birds are similar
to us in many ways
and at the same time
rather alien.

Lucy Aplin has just returned from Sydney. We are sitting with her at the round table in her office at the Department of Evolutionary Biology and Environmental Studies on the Irchel University campus. From the large poster on the wall, a good dozen cockatoos of all species and sizes are looking at us. We ask, what is it about birds that fascinates her so much? «Birds are so close to us; we encounter them almost everywhere, every day. They are one of the most successful species, evolutionarily much older than us, but just as intelligent as mammals. They are similar to us in many ways and at the same time rather alien. They have cognitive abilities, can learn and pass on knowledge, but their brains are built completely differently than those of mammals. A bird’s brain is small and compact, does not have the furrowed grey mass like that of mammals. But under the microscope we see that the density of neurons in a bird’s brain is very high, higher than in mammals. It contains almost as many neurons as the much larger brain of a mammal. But unlike mammals, there are no free spaces in a bird’s head. They have to keep their weight to the absolute minimum so that they can fly and they are very efficient at this, much more efficient than mammals.» We want to know whether there are any bird species that she particularly likes. Lucy Aplin smiles and points to the cockatoos on the poster. «I am particularly fascinated by parrot species. These long-lived intelligent animals have a pronounced social life, are very adaptable and can live in a wide variety of habitats.»

From the great tits

«Another bird species that excites me is the great tit,» Lucy Aplin continues. «I like it because it is so enormously adaptable. This little generalist can live almost anywhere and eat almost anything. The great tit is one of the few species that has been able to adapt very successfully to the habitat shaped by humans. Their population has almost doubled in Europe in the last 50 years. The reason for this is that great tits react very quickly to changes and can change their behaviour.» For her doctoral thesis, Lucy Aplin worked intensively with great tits. She investigated how new information spreads in a great tit population and showed that the social structure of great tits is almost ideal for this. To do this, the behavioural biologist conducted the following experiment: she taught some captured great tits (demonstrators) to open a small ‘puzzle’ feeder and access food by sliding a door to the left and other demonstrators to the right. After a week, she released the trained birds, placed the same puzzle feeders all over the forest and observed how the great tits reacted.

Birds learn by observing
and precisely imitating
the behaviour of
conspecifics.

The other birds watched how their trained conspecifics obtained the food at the boxes and began to imitate their behaviour. Within a very short time, the information spread among the great tits that food could be found in the box if the flap was pushed to the side. Because the birds copied and used the same side as the originally trained demonstrators (both sides were always equal and available), Lucy Aplin was able to prove that great tits learn new behaviours very quickly and that adaptations to new situations spread throughout the entire population in a short time. «Birds do not specifically pass on new behaviours. They learn by observing the behaviour of conspecifics and then imitate it. And they are very open to innovations. It took a week to teach the captured great tits the new behaviour. In nature, it took their conspecifics just five minutes from the moment of observation to the application of the new technique,» Lucy Aplin remarks. But how do birds in their habitat come to discover new opportunities and make use of them? There are studies from great tits that answer this, too. According to these studies, it is individual, particularly innovative «clever» birds that try out new things and play a pioneering role. «But the crucial point is: innovations are rare,» the researcher adds. «They may occur once or twice within a generation. But since information spreads very quickly among birds and they absorb the innovation, this is enough to change the behaviour of an entire population. Incidentally, we also observe this in cockatoos.»

to the cockatoos

This brings us back to the favourite bird species of the behavioural biologist. Cockatoos are widespread in Australia. Sulphur-crested cockatoos form large roosting groups in big cities like Sydney. Lucy Aplin has been dreaming of doing research on cockatoos since she was a student. A coincidence made the dream come true. «The opportunity arose when I visited my brother on holiday in Sydney during my PhD studies in Oxford. On the street I saw sulphur-crested cockatoos wearing wing tags. That’s cool, I thought, someone is doing research on cockatoos. Until now, hardly anyone here had worked with cockatoos. I contacted the research group and asked if I could use new methods to do social network studies on sulphur-crested cockatoos. They thought it was a good idea and I got a Visiting Fellowship at the Australia Museum in Sydney.» Lucy Aplin subsequently worked on several research projects at the Max Planck Institute for Behavioural Biology in Germany and at the Australian Museum in Sydney focusing not only on great tits but also on the popular white bird with a yellow crest of feathers on its head. «I was interested in how the culture of a bird population and the rapid dissemination of information contribute to the animals’ ability to continually adapt their behaviour to the changing environment, especially to rapid urbanisation. For this, the sulphur-crested cockatoos offered ideal conditions.»

and to the culture of birds

Lucy Aplin designed an ambitious project with which she wanted to investigate the culture and culture change of the sulphur-crested cockatoos from various points of view and find answers to a fundamental question of life: is the decisive factor for successfully opening up new habitats and thus ensuring the continuation of the species the ability to innovate, learn socially and form a culture, not only in humans but also in other species? The behavioural scientist understands the «culture of a bird population» as the sum of the skills and knowledge that the birds of a population have acquired through observation and that they share over a certain period of time and adapt to new conditions when necessary. With her project «CULTURES ADAPT», Lucy Aplin was awarded an ERC Starting Grant from the EU Research Commission, funded by the Swiss State Secretariat for Education, Research and Innovation (SERI). For the past two years, the behavioural scientist has been studying the population of sulphur-crested cockatoos in Sydney with two postdocs and two PhD students. She is focusing on three aspects. The first is about the different habitats, the food supply, the demography and the social structure of the sulphur-crested cockatoos in three different neighbourhoods in Sydney. The location, movement, feeding and calling behaviour of the birds are studied. Lucy Aplin and her team obtain the information through sophisticated systematic observation methods and through Citizen Science, the cooperation of committed residents who report their observations and experiences of sulphur-crested cockatoos via an app. The second aspect focuses on learning behaviour and the dissemination of innovations. To this end, Lucy Aplin’s team conducts diffusion experiments. They teach a selected breeding pair at each of three different roosts in the city to accept a new food or to fetch food from a feeder. The team then observes whether this behaviour catches on with the other birds at the roost and spreads to other roosts. The third aspect focuses on two mechanisms of cultural change: completely new innovation and cultural innovation due to changed resources.

A «cultural arms race»
is underway between
the population and
birds over access
to the rubbish bins.

Lucy Aplin designed her project based on her study «innovations for opening bins», in which she showed how sulphur-crested cockatoos manage to open bins in Sydney’s neighbourhoods with ever new tricks to get to food. The residents of the quarters weighted down the lids of their rubbish bins with stones. But the clever birds have quickly learned to push the stones off the lids and open the bin. There is a real «cultural arms race» going on between the population of the neighbourhoods and the birds for access to the bins. «The exciting thing is that a direct interaction between people and birds can be observed here, which mutually influences the behaviour of the birds and the people,» Lucy Aplin sums up.

The SERI-funded ERC Grant offers the ambitious researcher the unique opportunity to work for five years with a team on a topic in behavioural research, where findings only emerge over a longer observation period. «Innovations, changes in behaviour and the emergence of new cultures do not take place within days or weeks in birds. They take years. Thanks to this funding, my team and I can observe the same bird population over a longer period of time from different perspectives at the same time and thus gain new insights. Without this grant, I would probably have divided the different aspects of research that I can now tackle in parallel into individual projects and sought funding for them. But that would probably not have brought the same results.» What will she be dealing with when in 2027 the project is completed, we ask Lucy Aplin at the end of our conversation. «I will certainly continue to study the behavioural flexibility of birds and, of course, parrot species,» she replies with a wink. As we say goodbye to Lucy Aplin, it seems to me that the cockatoos on the poster on the wall are also winking at us.