Little drummer birds

Little drummer birds

Australia’s Palm Cockatoos have wowed the world with their drumming displays, and the instruments they craft for each performance. But is this an ancient behaviour, spawned thousands of years ago, or something they picked up from humans? Rob Heinsohn and Christina Zdenek speculate on the likely origin of this fascinating ability. 

This article appeared in the autumn 2024 issue of Australian Birdlife magazine. For more great reads, become a BirdLife Australia member and receive our quarterly, award-winning magazine in your mailbox. 

Wandering through the rainforests and woodlands of Kutini–Payamu (formerly Iron Range) National Park on Cape York Peninsula, you might be lucky enough to hear a steady tap, tap, tap coming from the forest edge.

With a lot of stealth you may track down the source of the sound, a gorgeous male Palm Cockatoo. Slaty-black with a massive bill, bright-red cheek patches, and tall erect crest, his left foot will be clutching either a stick or a grevillea seed pod, and he will be striking this ‘sound tool’ against the tree. He may occasionally pause to let out a piercing whistle or harsh cry, and probably has an audience – a female – just a few metres away, keenly watching his every move. 

Drumming in Palm Cockatoos was first reported to science in the 1980s by naturalist Graham Wood who noted how rare it is for animals to manufacture tools used in displays. In almost all other cases where non-human species fashion a tool, it is to help them find or process food. The classic examples include chimpanzees using twigs to retrieve termites, and the sophisticated probing tools of New Caledonian Crows. The manufacture of a drumming tool by Palm Cockatoos is unique among non-human species, and like human rock stars, they put their heart and soul into the performance. 

Our research on Palm Cockatoos over 25 years, including observing over 80 drumming events, has established strong parallels between their drumming and human music. Alongside the production of sound tools (effectively musical instruments), we found that they drum rhythmically, and that each male has his own distinct style. One cannot help but think about the famous human drummers who have their own drumming ‘signatures’ (we even dubbed two of the more prolific males Ringo and Phil, after drummers Ringo Starr and Phil Collins).

Some males were slow and steady in their beat, others were faster, and some added little flourishes between more regular rhythms. We found that drumming is part of a sophisticated display males use to impress females at mating time. The package includes head bobbing, crest erection, blushing the red skin on their cheeks, combinations of over 27 different types of calls, making the tool and, finally, drumming. Our observations also show that drumming plays a large role in territorial defence, and we have no doubt that males can tell each apart by their drumming signature alone.

The manufacture of a drumming tool by Palm Cockatoos is unique among non-human species, and like human rock stars, they put their heart and soul into the performance. 

Where drumming began

Although we understand why drumming occurs, it is less clear where and how it arose. Interestingly, drumming with tools is most common on the east coast of Cape York Peninsula around the Iron–McIlwraith Ranges, and occurs only occasionally in other populations on Cape York Peninsula (e.g. Weipa region, Bamaga). To our knowledge it has not been recorded in New Guinea, although males there stamp their feet without using a tool. This suggests that tool-assisted drumming arose on Cape York Peninsula, and most likely in the Iron–McIlwraith Ranges.

Australia is fortunate because, thanks to ancient land-bridges that disappeared when sea levels rose, many New Guinean species found their way to the southern side of the narrow Torres Strait. Examples include green pythons, spotted and grey cuscuses, Southern Cassowaries and Eclectus Parrots. Palm Cockatoos are also primarily a New Guinean species, where they occur in lowland rainforests. On Cape York Peninsula they occur in greatest density in woodland within one kilometre of the rainforest edge. A matrix of rainforest and woodland on Cape York provides large tracts of suitable habitat where they dwell in long-term pairs. Together, these pairs defend the scarce tree hollows and the extensive nest platform inside they need for nesting.

The ancient land bridges and changing climate give important clues as to why the east coast is the epicentre of Palm Cockatoo drumming. These land bridges have come and gone over the Pleistocene period for at least the last few hundred thousand years. For example, Australia and New Guinea were joined 150,000 years ago, but separated by 120,000 years ago. Then they were joined for at least 100,000 years before separating once more roughly 8,000 years ago. Over these periods the climate has periodically dried out, leaving rainforest very limited at times.

Throughout these fluctuations the rainforests of the Iron–McIlwraith Ranges persisted. Sometimes they joined a continuous expanse up and down the coast, and at other times they acted as an isolated refuge for rainforest-dependent species on Cape York Peninsula. Our research showed that the Palm Cockatoos on the east coast are in fact quite distinct from the others on Cape York Peninsula because of their long isolation. They are genetically different, have several different calls, and we also know that their rainforest habitat is only weakly connected to the rest of Cape York Peninsula. The fact that drumming occurs there so much more than elsewhere on the peninsula suggests that it started there and has been limited from spreading to other populations.

An old trick or a new one?

The questions of when and how Palm Cockatoo drumming arose are intriguing. It is entirely plausible that they started drumming a very long time ago (possibly hundreds of thousands of years), perhaps taking their habit of foot-stomping to the next level when excited during nest building. A drumming culture may then have persisted in the old Palm Cockatoo population that continually occupied the rainforest refuge of the east coast while other populations arose and died out.

We know that only a few other species understand rhythmic beats the way humans do, and these seem to be the ones that learn their vocalisations throughout life like songbirds, parrots and whales. The classic example is Snowball the Sulphur-crested Cockatoo, who is very good at picking the beat and bopping along in time to popular music. Palm Cockatoos regularly handle sticks when building the nest platform inside the hollow, so it’s possible that long ago, a creative male might have started tapping a stick against the tree trunk and found doing it rhythmically the most pleasing. If a watching female showed her approval, then say no more.

More recently we have tried flipping this thinking on its head and, given the strong analogy of their drumming with human music, wondered if there is a more direct link between Palm Cockatoos and our own species. Could the Palm Cockatoos have learned how to drum rhythmically by watching humans do it? After all, one of the abilities people value so much in pet parrots is their remarkable ability to imitate.

We can think of two ways this second scenario might have unfolded. Palm Cockatoos, though there first, have shared the Iron–McIllwraith area with Indigenous people for at least 60,000 years. The Kuuku Ya’u, Wuthathi, Kanthanumpu, Uutaalnganu, Umpila and Kaanju peoples of that region used drums and have highly rhythmic ceremonial music and dances. It is not hard to imagine a spying, eavesdropping male Palm Cockatoo starting to tap his foot to the beat. There would have been many opportunities over the millennia for this to develop into tapping with a stick or pod, and for it to spread throughout the population.

The second possibility is that the drumming was only copied from humans in the last few decades under entirely different circumstances. Palm Cockatoos come into Lockhart River, the major community near the Iron Range, in the dry season to forage on beach almonds. They are culturally important to the local people, very tame, and spend a lot of time feeding in the yards of houses with big beach almond trees. This means that they are often up close and personal with the people, sometimes even peering in the windows from tree branches. The newer Lockhart River (24 kilometres north-west of ‘Old Site’) was established in the 1960s, just when people started using big speakers to play loud rock music. We think it’s entirely possible that Palm Cockatoos started to appreciate a rhythmic beat at this time. One piece of evidence that supports this idea is that the tempo of upbeat 1960s and 1970s rock music (such as the Rolling Stones) averaged about 120 beats per minute, which is exactly the tempo Palm Cockatoos prefer. Again, a bright male Palm Cockatoo may have watched, listened and started tapping his foot, then a tool, to the beat. The quick spread through the entire population could have occurred via a cultural revolution such as those seen among birds and whales where entire song cultures can change in just a few years.

The hypotheses about how and when drumming by Palm Cockatoos arose all seem plausible and at this stage are hard to tease apart, although we are fairly confident that it started in the Iron–McIllwraith Range area. Our research on their conservation has recently led to a strong case for them to be uplisted to Endangered in Australia. The birds face many threats and the small population in Australia is declining quickly. We feel more hopeful now that we can argue their case to improve funding for conservation research and get them the protection and land-management they need. Our demonstrations of just how remarkable their drumming behaviour is, and indeed how alike they are to humans, can only help the cause.

Rob Heinsohn is a Professor of Evoluntionary and Conservation Biology at Australian National University, and Christina N. Zdenek is a postdoctoral researcher at the University of Queensland. They started the Palm Cockatoo Project in 2009. 

Not so little drummer bird…

Also known as the ‘goliath’ cockatoo, the Palm Cockatoo is Australia’s largest parrot, measuring up to 60 centimetres in length. They live for a long time – possibly as long as 90 years in captivity, though their lifespan in the wild is unknown. Like many cockatoos, Palm Cockatoos are very intelligent, and have so far evaded any attempts to capture and tag them so that more can be learned about their habits and movements.

Palm Cockatoos are slow breeders, with females laying only one egg every second year. With their high rate of nest failure, each pair generally raises only one young every ten years – not nearly enough to halt their rapid population decline. There are thought to be about 1,500 Palm Cockatoos left, and this number is predicted to halve in the next three generations.

Palmies are ‘picky breeders’ according to Zdenek, and the shortage of suitable tree hollows is a huge problem for the species. Inappropriate fire regimes, along with land clearing for bauxite mining in the Weipa area, are the main cause of hollow shortage. Zdenek’s team has put many hours into clearing around the base of precious nesting trees to save them from fires, but this is only a short-term solution to problem that requires better protection of habitat, and a return to the ‘cool burns’ employed by Indigenous people, to maintain and protect the habitat that Palm Cockatoos need.

Thanks to the research carried out by Heinsohn and Zdenek and their colleagues, the Palm Cockatoo was uplisted to Endangered under Queensland law in 2021. At a federal level, the Palm Cockatoo is still considered ‘Vulnerable’, though Heinsohn and Zdenek’s research, along with the most recent Action Plan for Australian Birds, recommends an Endangered listing. Late last year, the Palm Cockatoo was included on the IUCN Red List for the first time.

Our research on their conservation has recently led to a strong case for them to be uplisted to Endangered in Australia…we feel more hopeful now that we can argue their case to improve funding for conservation research and get them the protection and land-management they need.

Our demonstrations of just how remarkable their drumming behaviour is, and indeed how alike they are to humans, can only help the cause.