Palm cockatoo populations projected to halve in 50 years
Ornithologist Robert Heinsohn has been studying palm cockatoos for more than 20 years. He was one of the first people to record their famous ‘drumming’, where the bird fashions a drumstick from a loose branch and begins banging it on a tree. Each cockatoo has its own rhythm, choosing different combinations of tree-tapping, squawking and wing flapping, hence its species’ nickname ‘Ringo Starr’.
“When I see a palm cockatoo performing its display in the remote forests of Cape York Peninsula [Queensland] my spine tingles at the privilege of having been allowed to study them for so long and look into the inner workings of their private world,” Rob says.
But in a new paper, published today in Biological Conservation, Rob, along with his colleagues at the Australian National University, are sounding the alarm.
According to the research, populations of palm cockatoo, of which only an estimated 2000 are left in the wild, are projected to be half the size in 50 years. Palm cockatoos produce one successful offspring every 10 years. This slow reproduction rate, paired with the threat of habitat destruction, has set the palm cockatoo on a dangerous trajectory.
There are three existing populations of palm cockatoo in Australia, all within the Cape York Peninsula. There’s one within the Iron and McIlwraith Ranges on the eastern side of Cape York, a population within the inter-connected patches of rainforest on the western side of the Great Dividing Range, and a population within the forest patches closer to the tip of Cape York.
Using data from a long-term monitoring project and new information about breeding biology, the researchers examined exactly how connected these three individual populations of palm cockatoo are, and found that good breeders in one population were not compensating for the lower reproduction rates of another population.
“We worked out that the other populations are not doing well enough to support Kutini-Payamu National Park (east) – in fact the opposite occurs and Kutini-Payamu is a ‘sink’ that causes the other two populations to also decline,” Rob says.
The poor outlook for the palm cockatoos makes it eligible for an endangered listing through the International Union for Conservation of Nature (IUCN), which the researchers believe is a critical next step.
“Our paper is a clarion call to governments and the public saying that we risk losing palm cockatoos in Australia if we don’t find ways to arrest their slide,” Rob says
“They are very long lived and occupy habitat in remote areas. It’s taken incredibly hard and arduous work over 20-plus years to work out their conservation status.
“We hope that the very bad news that they qualify as endangered will provide the impetus to provide them with more active protection and management.”
The east coast population of palm cockatoos isn’t reproducing quickly enough to replace birds that die naturally. “The population is in fact likely to be ageing, just like human populations when the birth rate drops too low,” Rob says.
On the west coast, he says a lot of palm cockatoo habitat is being lost to broad-scale habitat clearing for bauxite mining. “Over 5000 square kilometres of bush are ear-marked for clearing for bauxite mining in the next 20 years making it essential that mining companies find improved ways to identify and preserve palm cockatoo habitat.”
Less than ideal land management is also taking its toll. “Palm cockatoo habitat is being badly affected by large fires that burn the woodland and destroy nest hollows each dry season. Fire regimes have changed since Europeans started managing the landscape and are much ‘hotter’ and more destructive these days.”
Rob says the paper is a clear warning. “We hope this analysis shows that we cannot take the apparent continuing presence of palm cockatoos for granted.
“It’s too easy to just assume that all is well in the remote north of Australia. But all is clearly not well, and we hope this ‘warning shot across the bow’ enables conservation actions to save the species while there are still sufficient birds left for this to be possible.”