Monday, May 26, 2008

Calyptorhynchus funereus

A flock of Yellow-Tailed Black Cockatoos wheeling slowly over the trees calling to each other with long wailing cries sounding like “whee-la” is one of the characteristic sights and sounds of the timbered country of eastern Australia from Rockhampton in Queensland to Tasmania in the south.

They are predominantly seed eaters but also love to eat larvae of timber boring insects, nectar, pollen and some blossoms when in season.

The flocks we see at Easy Street Retreat compete with the winter flocks of Sulphur Crested White Cockatoos to get at the pecan nuts in the trees on the neighbour's property. The sulphurs obviously don't like competition from the yellows and usually win the harrassment wars that go on when the two species are vying for the same food. The superior numbers of the sulphurs obviously helps. Here's one of the Yellow Tailed Cockatoos, probably a female, with ruffled feathers on a windy winter's day in a red ash tree next to our house:

We rather like the long mounful cry of the Yellowed Tailed Cockatoos and prefer it greatly to the screeching car wreck cry of the Sulphur Cresteds.

They grow up to 800 mm long. Their body plumage is dusky black, with feathers narrowly edged with yellow especially on under parts. They have a small yellow patch on each of their cheeks which is brighter and larger on the female, and a broad band of yellow near the end of the tail with centre tail feathers black. Feet and toes are grey/brown. The male has a dark grey beak while the female's is bone coloured. Chicks are covered in yellow down.

Both sexes construct the nest by chewing the inside of hollow branches to make woodchips high up in large living or dead trees. They usually come back to the same spot to nest year after year. These sites can be 2 – 30 metres up. They usually lay two eggs. After 3-4 weeks continuous incubation by the female, being fed by the male, the gangly completely dependant chick is hatched and fed a diet high in protein from insects and larvae. All cockatoo parents enter the hollow nest backwards – tail first! Usually only one yellowed downed chick survives, and it will stay in the care of its parents for about six months.

They are slow, powerful and buoyant flyers with languid wing-beats. Some people say that they fly away from rain and that a flock flying off into the distance can signal the onset of rain or a storm. With inland drought over the past few years and deforestation of their natural environment more and more Black and White Cockatoos seem to be flying over the great Dividing range to live and find feed and breed with us nearer the coast.

To help these beautiful birds continue, there are some practical things that we can do. Planting Australian native trees is a good start. Banksias, Eucalyptus, Acacias, Casuarinas, Hakeas are suitable. Existing stands of trees where possible should be retained and extended. Old hollow branches on living trees should be retained and dead trees should also be retained. Wooden nesting boxes can be provided in the breeding season between March and October. We can assist with the protection of nest sites from disturbances by feral cats, or birds such as the Indian Mynah. Feral cats can be trapped. Traps for Indian Mynahs, which compete with native birds for nesting sites, can be purchased on the World Wide Web. Domestic cats can be kept inside at all times and provided with a caged run for outdoors. The natural instinct of a cat is to hunt and they hunt both in the daytime and at night. Unwanted cats and kittens should never be dumped. They should be taken to an animal shelter. Doing just one of these things will help to protect cockatoos for future genetations to admire and enjoy.

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