Biology and breeding of the Red-tailed Cockatoo. PART I

January 27th, 2016 | by Julie and Barry Blanch
Biology and breeding of the Red-tailed Cockatoo. PART I

Red-tailed Black Cockatoo are found in most Australian states and territories except for the Australian Capital Territory (situated in the southern part of New South Wales), and Tasmania.

This species can be noisy and boisterous especially in the evening or diurnal and are often seen flying high overhead in small flocks, sometimes mixed with other cockatoos. The Redtails usually fly at considerable height and tend to fly rather slowly with intermittent deep flapping wingbeats.

Generally, the Redtails can flock up to 500 birds especially in the north eastern areas or when the birds are concentrated at some food source. Otherwise, they are normally rather shy of humans. Most of the Red-tailed Cockatoos are not considered to be completely migratory although some subspecies will exhibit some annual seasonal movement following food sources.



In northern and central Australia the Macrorhynchus, Magnificus and Samueli will often forage on the ground. During the summer wet season in the northern parts and areas experiencing high humidity in the Northern Territory both the Macrorhynchus and Magnificus will fly to the south of their range. The Naso subspecies also move to the north of their range after breeding following the fruiting and maturing seed pods of the Kauri and Mauri trees. Graptogyne in the south eastern regions move throughout their range following the seasonal availability of their preferred food the Brown Stringy bark and Allocasuarina luehmannii (buloke) nuts.

The two southern subspecies – the Graptogyne and Naso, are almost exclusively arboreal and are rarely observed feeding on the ground.

a)Macrorhynchus – prefer solitude and typically fly only in pairs or in a trio

b)Magnificus – are large flock birds.

c)Samueli – both Northern and Coastal Wheatbelt Samueli are regarded as flocking birds although degradation of land for agricultural purposes in some areas of southern Queensland (QLD), northern New South Wales (NSW) and some Western Australia (WA) mid central and inland areas.

d)Graptogyne – will flock but during the breeding season keep to the family group

e)Naso – we have observed a flock of approx. 25-30 birds drinking at a roadside waterhole at sunset during early April and then breaking up into smaller groups on dark and during the early morning hours.



Wild Calyptorhynchus banksii banksii, female(c) Lubomir Tomiska


Wild Calyptorhynchus banksii banksii, male (c) Lubomir Tomiska



These unique cockatoos are found in varying habitats that range from dense tropical monsoonal and subtropical rainforests of Northern Australia (Macrorhynchus and Magnificus) down to shrublands and grasslands through eucalypt, she oak or bulokeand acacia woodlands in Central and Southern Australia (Samueli). The bird is dependent on large, old eucalypts for nesting hollows, although the specific gums used vary in different parts of the country.

In the south the subspecies also inhabit areas of dense eucalypt forest and sparsely timbered grazing country. Habitat loss in some areas of both C. b. naso and C. b. graptogynedue to deforestation for logging and agriculture — has directly resulted in decreased populations in their respective range. However recent land recovery programs are raising awareness by encouraging landholders to implement improved management of affected habitats.

The bird is dependent on large, old eucalypts for nesting hollows, although the specific gums used vary in different parts of the country.



Distribution map (c) J & B Blanch


Macrorhynchus (C. b. macrorhynchus)

Found in the northern parts of Arnhem Land and Kakadu in the Northern Territory through to the Kimberley region and the north-west coast of Western Australia. There is only 2 seasons in these areas – monsoonal ‘wet’ and ‘dry’ with either the seasonal summer downpour rains or hot dry winter months.

This harsh region experiences high recordings of rainfall of 1500 mm in the summer wet season. The high rainfalls, from November–April with associated humidity, very hot temperatures 33° – 39° C allows large amounts of vegetation, especially the grasses to flourish and grow to up to 1 metre in height.

By late winterit is dry, with very little to no rain and slightly cooler mid -year temperatures 31°- 33° and it is not uncommon for 80% of all tinder dry vegetation areas to be burnt, mostly unchecked. In some areas there is small yearly control burning fire regimes instigated to clear the grassland habitats. The Macrorhynchus take advantage of the after effects of the fires and have been recorded foraging for grass seeds and wood larvae. They consume sorghum grass seeds, fruits and flowers of the eucalyptus, acacias grevillea, banksia and melaleuca trees and shrubs.



Macrorhynchus females have creme tail feathers, not orange like in other subspecies (c) Lubomir Tomiska


Breeding in the wild is during the dry season months, March to early July while in the aviary situation our records have found the breeding season can extend over a longer period from March until early August. Nesting sites are usually relatively close to a water source. In the Kimberleys there are the unique bloodwood (Eucalyptus collina) and Red Gum (Eucalyptus camaldulensis) that the macrorhynchus will nest in.

The C. b. macrorhynchus birds mature into their adult plumage from their 4-5th year. The young cockbirds retain the ‘spots’ well into the 4th year. Aviary bred Macrorhynchus have been known to commence breeding before obtaining their complete adult plumage. Mature female macrorhynchus are heavily marked with’ spots’ especially on the wing bend while the mature male bird has a sooty black body feathering with a long black vent and blood red wide baring in the tail. The young chicks are larger and have sparse body down and a distinct bald patch on the crown, although not scientifically proven distinguishes them from both the smaller Samueli and the larger Magnificus.



Magnificus (C. b. banksii)

Also known as ‘Magnificus’ this subspecies is predominantly found in both tropical savanna inland and coastal rainforest areas of northern Queensland. The range these large birds inhabit is a large area from the Gulf region and Cape York Peninsula in the extreme north down to the Fraser Coast region in the south of the state, particularly during the winter months. Magnificus are nomadic within their habitat.

There are a number of habitats in the vast far north including dry scrubland, mangrove swamps, monsoon forest and flood plains. In the far northern regions during the mid- summer months – December through to March, (better known as the big wet season) when temperatures range from a humid 33° C – 40° C+  influenced by yearly tropical monsoons, cyclones and unstable conditions resulting in huge rain falls of over 1800 mm and flooding.

During the extremely humid wet the birds move up to the high tablelands and out to the western drier areas or to more southern areas where conditions are not as humid and temperatures are slightly cooler. The daily temperatures in the north during the dry winter months, May – October range 12° C (overnight) – 27° C, conditions can remain humid and in some inland areas become drought like, as the rainfall is variable.



Calyptorhynchus banksii banksii represents one of two larger subspecies (c) Julie & Barry Blanch


Massive numbers of Magnificus flock, up to around 1500 birds and more, during the dry season months and are considered pests by small crop farmers especially those that grow peanuts. In some areas permits are issued to farmers to shoot the foraging birds in an attempt to deter these cockatoos with little to no impact. Controlled burning of extensive grassland areas is carried out during the ‘dry’ season – November through until April, especially in the grazing, north western gulf areas causing loss of some breeding sites and food supply. There are reports of Magnificus foraging on the ground for seed, larvae and grubs.

Conditions during the winter months June through September throughout the more southern areas of their range there is very little to nil rain. Although some areas with considerably milder conditions, from September through to November can expect rainfalls between 17 mm- 50 mmto fall providing abundant food sources for the birds.

Magnificus gain their mature plumage and begin to breed during the 4th year. Depending on the season these birds usually have a slightly longer breeding season than the Macrorhynchus. In the aviaries our Magnificus breeding season commences early April with some birds still laying mid-September. Some of the birds from areas that overlap in the Macrorhynchus subspecies natural range can exhibit characteristics of both with creamier barring in the tails of the hens and male birds having a larger beak.




author: Julie and Barry Blanch, Australia

Title photo: (c)Peter Campbell. This file is licensed under the Creative Commons Attribution-Share Alike 4.0 International, 3.0 Unported, 2.5 Generic, 2.0 Generic and 1.0 Generic license.  GNU Free Documentation License


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