Appearance

Male Red-tails have glossy black plumage with stunning, bright red tail panels. Females are quite different but equally spectacular – they are one of the most brightly marked subspecies of Red-Tail.

They have duller brown-black plumage but the feathers of their head, neck and parts of their wing are speckled with yellow. Viewed from below, their body is barred in pale orange-yellow. Their tail barring can be almost all pale yellow or pale yellow grading to pale orange-yellow at the tip. Females have an off-white bill which one volunteer suggests looks like the birds are carrying golf balls! Males have a grey bill. Juveniles are difficult to distinguish from adult females from the age of 1 to 3 years.

Seasonal Behaviour

Through Spring and early summer, the breeding season, Red-tailed Black-Cockatoos are generally seen alone or as family parties of 2 to 3 birds. During autumn and winter it is more common to see the birds in larger flocks. Several flocks of 100 birds and a single flock of 245 birds were seen during the 2005 annual count.

Range and habitat of the South-eastern Red-tailed Black-Cockatoo

Click image for enlargement (pdf Format)

 

Feeding

Red-tailed Black-Cockatoos are specialist feeders, relying almost entirely on the seeds of Brown and Desert stringybark (Eucalyptus baxteri and E. arenacea) and Buloke trees (Allocasuarina leuhmannii).Clearing of these feed trees is considered to be the main threat to long-term survival of Red-tails. Unlike Yellow-tails which happily feed on seed from introduced plantation pines, Red-tails haven’t found an alternative food source.

Management of remnant bushland also impacts on seed production. Too frequent burning of stringybark forest has been shown to contribute to reduced seed crops (Koch 2004). Stock grazing, particularly by cattle, results in ringbarking. This is mainly due to cattle rubbing up against the trunk. Eventually this leads to the tree dying.

Ringbarked stringybark

Dr Paul Koch, a biologist researching factors influencing food availability found that some food shortages are natural and due to Desert Stringybark fruiting on a three year cycle and Brown Stringybark on a 2-4 year cycle. Red-tails will feed on the species that has fruited most recently, preferring the softer seed capsule. Stringybark will retain the seed in the capsule on the tree, however as it matures, it hardens and requires more time and effort to extract the seed. This is critical for a nesting pair as it means the nest may be left for unusually long periods of time, resulting in nest failure.

 

Effects of Fire on Food

The amount of seed produced by stringybark trees is substantially reduced for up to 10 years following a fuel reduction burn or wildfire.  In order to maximise the amount of seed available for Red-tails the Department of Sustainability and Environment will limit fuel reduction burning in stingybark forest within the range of the Red-tail.  DSE is also investigating low intensity fuel reduction burning techniques to reduce the impact on stringybark seed production.  Timing fuel reduction burns to avoid years in which stringybark forests are carrying heavy crops of newly matured seed capsules will also help to minimize the impact of fire on Red-tail feed trees. 

Remnant buloke is mostly restricted
to roadside remnants or scattered paddock trees

Buloke occurs on heavier, more fertile soils favoured for agriculture. Only about 2% of buloke remains across the Red-tails range. The birds move to Buloke areas in late summer and autumn to feed on the seeds. Unlike stringybark, buloke does not retain the seed in the capsule. 

Stringybark woodland

Red-tails leave a tell-tale litter of twigs and chewed capsules (“chewings”) beneath their feed trees

Scattered paddock trees  (Research undertaken by Department of Sustainability and Environment predicts that based on current rates of clearing no paddock buloke will remain by 2040. )

Areas where centre pivots are being installed recorded loss of scattered buloke as high as 39% over a 15 year period from 1982 to 1997.

 

Fuel reduction burn

 

Nesting

As with many other parrots and cockatoos, Red-tails nest in deep hollows that have formed in very large, old eucalypts. Most nest sites are found in Red Gums (E.camaldulensis) but Red-tails will also nest in stringybark (E.baxteri and E.arenacea), Manna Gums (E. viminalis) and Yellow Gums (E.leucoxylon). Some of these trees are more than 200 years old.

Many nest sites are in farming paddocks in dead trees, ringbarked over 100 years ago to improve pasture. Legislative changes have been introduced across the Red-tail range to protect these trees. Hollow trees benefit lots of birds, mammals and insects that are beneficial to farmers because they eat agricultural pests. Where possible it is of great benefit to retain them. If landholders wish to remove dead, hollow trees advice should be sought from a local Department of Sustainability and Environment Office in Victoria or Department of Environment and Heritage in South Australia. Refer to the Contacts page.

Protecting trees with hollows, encouraging natural regeneration and planting for the future will help to ensure that Red-tails have access to suitable nest trees both now and in the future.

Nest trees are collared with galvanised iron to prevent Brush-tailed Possums taking eggs or chicks from the nest. 

Signage to promote legislative change

During the breeding season (spring and early summer), Red-tailed Black-Cockatoos are generally seen alone or as family parties of 2 or 3 birds. Red-tail chicks take a relatively long time to fledge – it’s almost 3 months from when they hatch to when they can leave the nest.

This places extra pressure on the parents as they are restricted to sourcing food from areas within a few kilometers from the nest. A major cause of nest failure in years when seed availability is low has been attributed to females leaving the nest to supplement the food brought to them by their mates (Jarmyn 2000).

South-eastern Red-tailed Black-Cockatoos
incubate a single egg

A chick at about 1 week of age

A chick at 5 weeks

Juvenile males closely resemble adult females in plumage characteristics until they are about 3 years old.  (Female bird to the right)