Palm Cockatoos – The Rock Stars of the Rainforest

Anyone who knows me outside of my zookeeper uniform knows that I am a massive heavy metal fan. Give me a sludgy breakdown and a mosh pit any day. So, it should come as no surprise that some of my favourite birds at the park are the ultimate rock stars of the avian world, the goliath palm cockatoos (Probosciger aterrimus). I think their punk-rock crests and entirely midnight-black plumage give them a really alternative vibe. We are incredibly lucky to have four of these gothic birds here at the park, Johnny and Nora and their two youngsters, Bernie and Ernie.

In the wild this species calls the rainforests of New Guinea, the Aru Islands and the Cape York Peninsula in Australia home. They are the largest cockatoo in the world, stretching up to 60cm in length and weighing in at over a kilogram. They also have a flash of red skin on their cheeks, and the depth of the colour there can vary depending on their mood from grey to crimson. If they are feeling shy they can fluff their feathers up to completely cover up this patch of bare skin.

Goliath palm cockatoos are canopy dependent, diurnal birds. They spend their mornings foraging in pairs or small family groups, communicating through an incredibly complex vocal repertoire that includes piercing whistles and harsh screeches. They have specialised feathers which are coated in a fine, powdery down which they spread over themselves when they preen to help keep them dry during heavy rainforest downpours.

Everything about these birds is built for survival in the tough rainforest canopy. Like all parrots, they have zygodactyl feet, with two toes facing forward and two facing backward, which give them a vice-like grip on swaying tree branches. Their beak is so strong that they can effortlessly slice open hard fruits and crack tough nuts that we would need to use a nutcracker for. Their bill shape is also completely unique as the upper and lower mandibles do not fully meet, leaving a gap where you can see their red, black-tipped tongue which contains a specialized bone that allows the bird to use it like a human uses an index finger. It is also packed full of nerve endings, the perfect appendage to expertly hold and peel food inside their mouth.

If you think their looks are wild, wait until you hear about their behaviour in the wild. They are the only bird in the world known to manufacture and use its own musical instruments. Males will break off a thick branch from a tree, hold it in their foot and tap rhythmically against a hollow tree cavity to amplify the sound, creating a thumping beat that can be heard up to 100 meters away! What’s even cooler is that researchers have noted every male has his own unique drumming style and signature rhythm. They are also incredibly meticulous, males don’t copy each other’s instrument designs, making drumsticks tailored to their own personal preferences. While we don’t see Johnny break off sticks very often, he absolutely loves stomping his feet to create a rhythmic beat. As a metalhead, watching their courtship display is one of my absolute favourite things to witness at the park.

Their nesting habits are just as hardcore. Unlike other cockatoos that look for sheltered tree hollows, palm cockatoos nest in massive, open-topped hollows. To stop their eggs from getting waterlogged during tropical downpours, they line the bottom with a thick, porous mattress of chewed-up twigs. Rainwater flows straight through this natural drainage system, keeping the egg safe and dry. Watching Johnny and Nora creating matchsticks of wood and dropping them into their nest is a key breeding behaviour we look out for here at the park.

When it comes to the actual breeding cycle, these birds don’t rush anything. After a successful drum-solo courtship, the female lays just a single egg per clutch. Both parents share the duties during an incubation period of 30 to 33 days. Once the chick hatches, the real marathon begins. Palm cockatoo chicks take an incredible 100 to 110 days to fledge. That is the longest fledgling period of any parrot species on the planet! Even after they leave the nest, the youngsters stay fully dependent on their parents for several weeks while they learn to fly and navigate the canopy. To sustain all that growth, their diet consists of some of the most nutrient-dense foods in the forest. They mainly target the oily nuts of the Canarium (kanari) tree, alongside various wild fruits, pandanus palm nuts, and leaf buds, as well as insects and wood-boring larvae. Their exact lifespan in the wild remains unknown to science, but like most parrots they possess unbelievable longevity in zoological care upwards of 50 years.

Sadly, life in the wild is becoming difficult for these incredible birds. Goliath palm cockatoos are listed as Near Threatened on the IUCN Red List, and their populations are rapidly declining due to a number of threats.

A big issue for these birds is that they have an incredibly slow reproductive rate. They don’t start breeding until they are around 7 or 8 years old and females only attempt to breed once every 2.2 years on average. Because of this, their natural breeding success rate is the lowest of any parrot species with a wild pair often only raising one chick successfully to adulthood every ten years.

Habitat loss from agriculture, mining and logging is destroying the ancient trees they rely on for nesting. Additionally, this species faces direct pressure from targeted poaching for the pet trade, localized competition for nest hollows from other birds and severe storms that destroy their habitats driven by climate change.

Their low reproductive success also means they are incredibly difficult to breed in zoos as well. They have a complex courtship and can be very picky with choosing a mate and often delay their first breeding attempt. Johnny and Nora joined us back in the Spring of 2020, and while they were showing all the exiting signs of breeding, they kept failing at the egg stage, damaging their eggs before they could hatch. Our two youngsters, Bernie & Ernie, were hand-raised by the park’s owner, Tony. He is always sharing updates and live streams on his TikTok channel, so make sure to follow TikTok Tony (@ant4w) to see what they are up to. I’m keeping my fingers crossed that we’ll be able to find breeding partners for these two when they mature in the future, even if that means they eventually move to a different zoo to support the species.

If you would like to see our palm cockatoos you can find Johnny and Nora next to our hyacinth macaws. As for the youngsters, Bernie and Ernie, they can currently be found in our aviaries right opposite their parents in our long flight aviary for now. We often get asked if they make good pets, but parrots are definitely not your average cuddly companions. They are highly intelligent, incredibly loud and destructive, and demand a massive amount of specialized care. But for a bird nerd and metal fan like me, spending my days around them makes this the best job in the world. Next time you are passing the aviaries, see if you can spot their rock-and-roll personalities in person!

By Becky, Head of Birds