BOOBOOK ECOLOGICAL CONSULTING

Insights

The unique charm of Australia’s Glossy Black-Cockatoo

A Glossy Black-Cockatoo feeding on Casuarina seeds

Australia is lucky enough to have six different black cockatoos. Five of these are reasonably closely related to one another. The sixth, the huge Palm Cockatoo of northern Cape York, is a quite different bird altogether and also occurs in Papua New Guinea. The smallest of the remaining species is the Glossy Black-Cockatoo Calyptorhynchus lathami. They are sometimes referred to as “Glossies”.

Distinctive characteristics and appearance

The Glossy Black-Cockatoo is a medium sized bird, 48cm long with a weight of up to 420 grams. To put that in perspective, it’s about one-and-a-half times the size of a Galah, with an obviously longer tail. Glossies have mainly black plumage, but their tails have striking panels of colour, easily seen as the bird flies away. Males have solid bright red panels, while those of females are orange-red and yellow, with black bars across them. The females also differ from males in having extensive patches and scallops of yellow on the head. Interestingly, some recent work has shown that it is possible to identify individual females by their unique patterns of yellow on their heads.

A collection of Glossy Black-Cockatoo tail feathers
Photograph: Jill Shepherd

Juvenile birds differ from their parents in having many small yellowish spots over their breast, upper wings and head. Glossies can be confused with the Red-tailed Black-Cockatoo, but that bird is much larger and has a prominent rounded crest that it raises when excited or alarmed. Their ranges overlap in inland southern Queensland, but Glossies prefer dense forest types.

Though glossies do have a distinctive wheezy wailing call, they are generally quieter than other black-cockatoos, indeed all the cockatoos. Quiet and unobtrusive for most of the time, they are probably easily overlooked unless one hears them chewing their food – more on that later.

Habitat and distribution

Glossies are found from eastern Victoria northward to central Queensland. North-eastern New South Wales and south-eastern Queensland are strongholds for the species. Interestingly, at each end of their range there is an isolated population at a distance from their nearest neighbours. To the southwest, there’s a well-known and studied population on Kangaroo Island. In the north, it has only quite recently been discovered in mountainous country north of Townsville.

In south central Queensland Glossies are found in two distinct habitats: Brigalow-Belah forests on clay plains, and dry eucalypt forests and woodlands of hills. The reason for this is that they have a specialised diet, consisting of the seeds of several species of “she-oak”, which are in the Casuarina and Allocasuarina genera.

Feeding habits and specialised diet

Glossies chew the cones of trees such as Belah, Forest Oak and Hairy Oak, extracting the nutritious seeds from their hard, protective cover. A sure sign of the presence of these birds is the accumulation of chewed cones, termed “orts”, beneath trees where they’ve been feeding. Studies have shown that Glossies will sample the cones of a lot of trees but only occasionally stay in a single tree for extended feeding bouts. It seems they choose cones with the biggest seeds that provide the best return for the effort of chewing apart the tough cones.

A pair of Glossy Black-Cockatoos
Photograph: Brayden Stanford

Reproduction and parental care

Their specialised diet and their fussiness about choice of cones means that they require large areas of she-oak forest to support them. It also means that it’s hard work to produce young and Glossy pairs almost always produce only one young per year. That youngster lives with its parents for up to nine months, learning the ropes. Glossies nest in large tree hollows, usually in a eucalypt.

Conservation status and threats

Because these birds have a specialised diet patchily distributed across the landscape, and have a low reproductive output, they are at risk from loss of habitat. Clearing of “she-oak” communities, like the Belah forests, has left only small patches, not all of it containing high-quality cone-producing trees. Additionally, land clearing has reduced the availability of tree hollows.

Wildfires are another significant threat in removing feeding and nesting habitat. The huge fires of 2019-2020 burned over a third of known Glossy habitat and destroyed at least temporarily the “she-oak” layer in many forests, as well as burning down many hollow-bearing trees. These historical and current threats have caused Glossy Black-Cockatoo populations to decline, and the Queensland government has listed them as Vulnerable to extinction.

Conservation efforts and hope for the future

Glossies will travel across open country, moving from patch to patch. They would probably be in even worse circumstances if they did not have this ability. A patch of mature Belah planted at the Roma Bush Garden over twenty years ago has been visited by a Glossy family, as has an isolated tree on Long Gully. The Belah at these sites feature prolific production of large cones, choice food for the Glossies. This gives hope that replanting projects and protection of suitable nest trees will help keep the unique and lovely Glossies as a part of our landscape into the future.

For more information about local and endangered fauna please contact us, and for more specific information on the wildlife on your property please visit our fauna surveys page.

Main photograph in the header: Ken Griffiths

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