Creature Feature: Sulphur-crested cockatoo

Do you have moves like the cockatoo? Snowball the Eleonora sulphur-crested cockatoo (Cacatua galerita eleonora) knows how to move his body! Check it out:


Snowball’s killer moves resulted in more than a fun video. Prior to Snowball going viral in 2007, many scientists thought humans were the only species capable of musical beat perception and synchrony (BPS). Though “feeling the beat” comes naturally to us, it is actually a very complex process. BPS requires the grouping and segmentation of many different auditory inputs, statistical learning of pattern repetitions over time, and sensitivity to auditory and tonal hierarchies (e.g., knowing the “stable” tones within a specific key). Then, the neural pathways that process all of this information have to be synchronized with neural pathways for motor production [1]. In other words, BPS requires our nervous systems to process the complex musical sounds reaching our ears, recognize patterns in tone and rhythm, and then coordinate the auditory input with the motor output: our fancy dance moves.

Although Snowball’s bobbing and headbanging looks convincingly rhythmic, scientists did some tests to find out whether it was actually the result of BPS. They took Snowball’s favorite song (“Everybody,” as performed in the video above) and created new versions at different tempos. Indeed, Snowball adjusted the rhythm of his body in accordance with the rhythm of the song [2]. Further investigation revealed that the patterns of Snowball’s BPS also paralleled that of human children [3]. Snowball and human kiddos both have a preferred tempo at which they are most likely to move, regardless of the tempo of music being played. For Snowball, this was about 125 beats per minute: a bit faster than “Everybody” (108.7 beats per minute). Additionally, both Snowball and human children are more likely to synchronize their movement to songs with a tempo near their preferred tempo than to songs with faster or slower tempos.

The conclusion: humans and cockatoos both seem to have an internal beat that responds to the rhythms around us!

It is not just BPS that makes sulphur-crested Cockatoos special, though, but also the range of their dance repertoire. In follow-up studies with Snowball, he displayed a total of 14 distinct dance moves! This variety indicates he is not just repurposing habitual motions for mating and walking to dance, but spontaneously generating dance-specific movements [4].


I’ll be in the corner practicing my “shopping cart.”

Since Snowball, plenty of sulphur-crested cockatoos and other parrot species have been observed boogieing to their favorite jams. What makes these birds such good dancers? The leading hypothesis is that their innate vocal learning ability has equipped them with the perceptual and cognitive tools for BPS [5]. This would explain why parrots—with their diverse and developmentally acquired vocal repertoire—will dance spontaneously, but non-human primates do not.

Yet, many birds are vocal learners; only parrots are known to dance. There may be other factors at play. A bit of natural history is necessary to figure out what these factors may be [6].

Sulphur-crested cockatoos are one of twenty-one recognized species of cockatoos. All cockatoos are known for their elaborate crest feathers.

Illustrations of eight species of cockatoo. Image from White et al. [7].

Nested within the sulphur-crested cockatoo species, there are several subspecies. The Eleonora sulphur-crested cockatoo (including Snowball) is native to a specific region: the Aru Islands in Indonesia. Another subspecies, the greater sulphur-crested cockatoo (Cacatua galerita galerita), is much more widely distributed and can be found across much of Eastern Australia and Papua New Guinea, with introduced populations in Western Australia and New Zealand. Sulphur-crested cockatoos typically live in open woodland habitats, but can be found in a wide array of other habitats including grasslands and tropical forests [8]. The size of sulphur-crested cockatoo groups can vary drastically depending on season, time of day, and the abundance and distribution of food in the habitat. Communal roosts are often around 100 birds in size, but can reach up to 2000 [8]! Like many parrots, sulphur-crested cockatoo groups often include other species and have a fission-fusion structure; groups of birds will break off and come back together throughout a single day and over the course of a year. Though most members of the flock are free agents, male and female sulphur-crested cockatoos will form stable pair bonds that last years. These mated duos compete with other pairs for valuable tree cavities that are used for nesting.

Distribution of the greater sulpher-crested cockatoo. Native to orange regions, introduced in purple regions. Image from IUCN Redlist [Source].

In addition to their historical habitats, sulphur-crested cockatoos are also common in Earth’s newest habitat: cities.

Animals that thrive in our cities are often called “urban invaders,” though it is worth noting that this term can be misleading. In most cases the cockatoos were there long before the cities were.

One thing that sets sulphur-crested cockatoos apart from other urban invaders is their long lives. Successful urban invaders often have fast life-histories, meaning they reproduce a lot but have high mortality rates. Examples include rats, pigeons, and most invertebrates. With quick generational turnover, behavioral traits that allow animals to flourish in cities can spread quickly through populations of these species by natural selection. With enough time, these urban invaders may even become “urban exploiters,” specializing in city life and no longer found in their natural environment [9].

Sulphur-crested cockatoos are adept at living in urban settings, and are even considered a nuisance in some cities. Photo by Julian Berry [Source].

Thus far, sulphur-crested cockatoos have outlived all of our research efforts in the wild, so we do not actual know how long they live, only that it is a long time! We do know that they typically reach reproductive age around seven years. This is one of the longest juvenile periods in any bird! This long developmental period indicates a slow life-history, which describes species that have fewer young, but invest a lot of resources into reducing offspring mortality. Instead of adapting to cities through natural selection, it appears sulphur-crested cockatoos have adapted by behavioral plasticity—an individual’s ability to modify its behavior within its own lifetime.

In other words, sulphur-crested cockatoos likely adapted to city life by being flexible, combined with their natural intelligence and problem-solving ability. What we know about the brains of sulphur-crested cockatoos supports this hypothesis. For one thing, their brains are packed super-tight with neurons; at an average of only 10.1 grams, the sulphur-crested cockatoo brain contains about the same number of neurons as the 39.2 gram brain of a capuchin monkey [10]. Within the pallium, a region of the brain with many structures critical to vocal and spatial learning, the sulphur-crested cocakatoo actually has more neurons that most primates! Finally, relative to non-parrot birds and non-primate mammals, sulphur-crested cockatoos take longer to fully develop their neurons, a phenomenon referred to as delayed neural maturation that is associated with greater learning during development and higher rates of behavioral flexibility and innovation [10].

These traits have not always endeared sulphur-crested cockatoos to the citizens of Australia’s urban landscapes. Here you can see what happens when a sulphur-crested cockatoo decides it is NOT HAVING any pesky bird-spikes:


And this one was not going to let anybody stop it from finding a snack:


Cockatoos: 2, Humans: 0

In these videos, the sulphur-crested cockatoos show high motor coordination and the ability to string together sequences of actions to achieve their goals. Both of these skills are helpful in adapting to city life and may also be essential ingredients in BPS [4]. Does cockatoo cleverness play a role in their dancing? To learn more about cockatoo cognition, I spoke with Dr. Lucy Aplin, a Group Leader at the Max Planck Institute of Animal Behavior.

Dr. Aplin’s research group focuses on cognitive and cultural ecology, meaning they try to understand how environmental features shape the evolution of animal brains and societies. One of her projects takes her to Sydney, Australia where she studies how greater sulphur-crested cockatoos have adapted to the urban landscape.

The first thing Dr. Aplin noted when I spoke with her is that cognitive research with sulphur-crested cockatoos is very new, so it is hard to answer any questions definitively yet. But she doesn’t doubt for a moment that they are incredibly smart birds: “You can’t leave your things unattended. If you are not careful, they will unzip your backpack, empty its contents, open your lunchbox, and eat all of your food.”

I confirmed: she was speaking from personal experience.

But the cockatoos are not just out to eat scientists’ lunch. They engage researchers in all manner of social exchanges—from aggressive displays to friendly hair preening—just like they would with other cockatoos. “Often the cockatoos just want to play,” Dr. Aplin adds, describing a time she was following one bird, but two others tagged along by untying her shoes and using the laces like tow-lines.

A sulphur-crested cockatoo poses in Sydney © Wingtag Project.

These complex social interactions may be one element facilitating dancing behavior in sulphur-crested cockatoos. Cockatoos are capable of moving their crest feathers, and may combine these and other physical movement signals with their learned vocalizations to communicate. This integration of vocal and motor communication is another essential ingredient in perceiving and responding to musical rhythm [4]. Social interactions may also help sulphur-crested cockatoos learn other complex behaviors. A colleague of Dr. Aplin’s, Dr. Barbara Klump, has investigated bin-opening behavior. Dr. Klump’s research is still in progress, but so far suggests that sulphur-crested cockatoos may learn the necessary sequences of behavior by first watching other birds open bins.

To learn more about how sulphur-crested cockatoos build long term relationships in their flocks, Dr. Aplin needs data beyond what she can collect through personal observation. To get a sense of where large numbers of birds are moving, and who they spend time with, Dr. Aplin and her team are relying on citizen scientists.  Using the Wingtag app, anybody with an iPhone can take a picture of a sulphur-crested cockatoo that has been tagged and record its location. It turns out some of the cockatoos are quite gregarious, and many of Sydney’s citizens have built special relationships with the birds that come to visit!

By piecing together sightings by different citizens, researchers can keep track of many different birds over long periods of time, identifying behavioral patterns that would otherwise be much harder to detect.


So, in summary, sulphur-crested cockatoos are dexterous problem solvers and capable communicators. Their use of both vocal and motor skills to communicate has resulted in parallels between their brains and those of humans [11], such that we share the highly unique behaviors of spontaneously dancing to music and solving problems. What makes cockatoos so special? Why have they, of all animals, evolved these human-like skills?

“That’s the million-dollar question,” Dr. Aplin says. The benefits of being able to communicate within a large society have likely contributed to selection for their vocal learning abilities [6]. But living in a group is not a sufficient explanation. Though most of Earth’s smartest animals live in complex societies, plenty of group living animals have not evolved the sophisticated communicative and problem-solving skills of cockatoos. Perhaps the sulphur-crested cockatoo diet also plays a role. Sulphur-crested cockatoos are generalists that rely on many ephemeral food sources such as fruits and nuts [8] . Finding and extracting these foods efficiently requires good memory and strong motor planning [12].

Determining how and why a species’ environment selects for traits we consider intelligent will take hundreds of researchers like Dr. Aplin working together to compare factors across the globe. But as we learn more about understudied species like the sulphur-crested cockatoo, a better picture will emerge of why some traits like vocal learning and dancing are so rare.

If you want to play a role in this process, but do not live in Australia, this National Geographic site has useful tools to help you get involved in a variety of citizen science initiatives, including apps similar to Wingspan, like iNaturalist or eBird, that can be used all over the world.

It will take a long time for science to provide answers to these big questions. In the meantime, we have dance to bring us together. Take us out, Lucille!



Alexander Vining is a fourth year Ph.D. Candidate in the Animal Behavior Graduate Group. In affiliation with the Smithsonian Tropical Research Institute, he studies the spatial memory and movement of frugivorous mammals (including the kinkajou) on Barro Colorado Island, Panama. Alexander has a particular love for the elusive animals of the canopy and enjoys any research that brings him into the tree-tops. Follow his work on twitter at https://twitter.com/AVining_Opining


References

  1. Stevens, C. J. (2012). Music Perception and Cognition: A Review of Recent Cross-Cultural Research. Topics in Cognitive Science, 4(4), 653–667. https://doi.org/10.1111/j.1756-8765.2012.01215.x
  2. Patel, A. D., Iversen, J. R., Bregman, M. R., & Schulz, I. (2009). Experimental Evidence for Synchronization to a Musical Beat in a Nonhuman Animal. Current Biology, 19(10), 827–830.
  3. Patel, A. D., Iversen, J. R., Bregman, M. R., & Schulz, I. (2009a). Avian and human movement to music two further parallels. Two further parallels. Communicative and Integrative Biology, 2(6), 485–488. https://doi.org/10.4161/cib.2.6.9373
  4. Jao Keehn, R. J., Iversen, J. R., Schulz, I., & Patel, A. D. (2019). Spontaneity and diversity of movement to music are not uniquely human. Current Biology, 29(13), R621–R622. https://doi.org/10.1016/j.cub.2019.05.035
  5. Patel, A. D., Iversen, J. R., Bregman, M. R., Schulz, I., & Schulz, C. (2008). Investigating the human-specificity of synchronization to music. August, 1–5.
  6. Bradbury, J. W., & Balsby, T. J. S. (2016). The functions of vocal learning in parrots. Behavioral Ecology and Sociobiology, 70(3), 293–312. https://doi.org/10.1007/s00265-016-2068-4
  7. White, N. E., Phillips, M. J., Gilbert, M. T. P., Alfaro-Núñez, A., Willerslev, E., Mawson, P. R., Spencer, P. B. S., & Bunce, M. (2011). The evolutionary history of cockatoos (Aves: Psittaciformes: Cacatuidae). Molecular Phylogenetics and Evolution, 59(3), 615–622. https://doi.org/10.1016/j.ympev.2011.03.011
  8. Styche, A. (2000). Distribution and behavioural ecology of the sulphur-crested cockatoo (Cacatua galerita L.) in New Zealand.
  9. Partecke, J. (2014). Mechanisms of phenotypic responses following colonization of urban areas: from plastic to genetic adaptation. In D. Gil & H. Brumm (Eds.), Avian Urban Ecology: Behavioral and Physiological adaptations (pp. 131–142). Oxford University Press.
  10. Olkowicz, S., Kocourek, M., Luèan, R. K., Porteš, M., Fitch, W. T., Herculano-Houzel, S., & Nemec, P. (2016). Birds have primate-like numbers of neurons in the forebrain. Proceedings of the National Academy of Sciences of the United States of America, 113(26), 7255–7260. https://doi.org/10.1073/pnas.1517131113
  11. Jarvis, E. D. (2004). Learned birdsong and the neurobiology of human language. Annals of the New York Academy of Sciences, 1016, 749–777. https://doi.org/10.1196/annals.1298.038
  12. O’Hara, M., Mioduszewska, B., Haryoko, T., Prawiradilaga, D. M., Huber, L., & Auersperg, A. (2019). Extraction without tooling around-The first comprehensive description of the foraging- and socio-ecology of wild Goffin’s cockatoos (Cacatua goffiniana). Behaviour, 156(5–8), 661–690. https://doi.org/10.1163/1568539X-00003523

Main image of sulphur-crested cockatoo [Source]


Edited by Jessica Schaefer.

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