A cockatoo on the brink of extinction

Carnaby’s Black Cockatoo (Calyptorhynchus latirostris) family group. Photo: Sandra WallaceA BIRD with lifelong fidelity to its mate and a mournful cry is heading towards extinction in Western Australia. If it were allowed to happen, the demise of Carnaby's black cockatoo would echo the "lack of foresight and rank stupidity" that led to the Tasmanian tiger's extinction in 1936, according to former CSIRO wildlife research scientist Denis Saunders.

He says the bird's only hope is for large-scale conservation programs to be conducted in the state's southwest, a global biodiversity hot spot, to restore its habitat.

Saunders, a world authority who has studied the birds since 1968, says there are unsettling similarities between the cockatoo and the Tasmanian tiger. Both were once regarded as vermin and both had a bounty on their heads.

"In the space of just over a decade - from the 1960s when the bounty came in to the mid-1970s - Carnaby's black cockatoos went from massive flocks numbering several thousand birds to suddenly being in deep trouble," he says. For decades, the big, powerful-beaked birds were considered a threat to orchardists.

The birds also suffered from mass land clearing in the state's southwest that destroyed nesting sites and food sources and caused large flocks to disappear from more than 30 per cent of their former range.

The cockatoos can nest only in the large hollows of eucalypts that are at least 120 years old. Many old hollow trees were felled by land clearing or are on privately owned land. "That's why private landholders have such an important role in conserving these magnificent creatures," Saunders says.

The most ominous sign of looming extinction is a gradual drop in the growth rates of chicks, caused by a lack of food: "It marked the beginning of the end for many flocks." Saunders says farmers in the southwest have commented on the steep decline in Carnaby's black cockatoo numbers, but few other West Australians realise that the conspicuous birds with a mournful wee-lah cry are facing extinction. Flocks still fly over Perth on their way to Kings Park on the city's edge, "but where once huge flocks of thousands of birds blackened the skies, today those flocks are considerably smaller and in many places have simply disappeared".

The largest known population is found at Coomallo Creek, 200km north of Perth, but the breeding cohort has halved to about 45 pairs since scientific study of the flock began in 1969. Scientists are unclear whether the remaining pairs are new or older breeding pairs.

"This information is important because Carnaby's black cockatoos are long-lived birds that mate for life. If few young birds are replacing older pairs, then at some point in the future there could be a much steeper decline in breeding numbers as the older birds pass breeding age."

The cockatoos stay together even as they roam a vast triangle encompassing the northern coastal port of Geraldton, the inland wheatbelt town of Merredin and Esperance on the Great Australian Bight. "In 40 years of observing these birds, we have never seen pairs separate."

Saunders, who also is president of WWF Australia, says the bird's only hope is for humans to preserve habitats important to their survival. "If we don't set boundaries on coastline development and land clearing in every area of this eco-region we will almost certainly lose Carnaby's black cockatoo. But itwill only be one such casualty," he says.

"The southwest is home to thousands of rare plants and animals found nowhere else in the world, creatures like the tiny western swamp tortoise, the one-of-a-kind sunset frog and the noisy scrub bird, which was thought to be extinct until rediscovered near Albany."

Bob Pressey, a conservation planner based at James Cook University in Queensland, says a $360,000 mapping program is under way in the southwest to draw up practical ways of halting the region's loss of rare flora and fauna, including the Carnaby's black cockatoo. The WA Department for Conservation and WWF-Australia are jointly seeking up to $20million from the federal Government to carry out worksuch as fencing, control of invasive species and acquisition of remnant bushland.

"The southwest is loaded with unique species and there's no doubt about its global significance," Pressey says.

"It pops up on every international priority list as a biodiversity hot spot. Specifically, what we can do for Carnaby's and a bunch of other species is to retain the old trees and younger stands of trees."

Says Saunders: "If today's politicians are prepared to let Carnaby's black cockatoo go the way of the Tasmanian tiger, then the state should be prepared to lose many more rare species. Imagine what future generations would think of a government that allowed greed to wipe out a magnificent long-lived bird that is emblematic of the state."