A chip off the old block

3 January 2003


A pair of sulphur crested cockatoos with no respect for their historic surroundings have been spotted taking a bite out of the ancient stonework in the Quadrangle.

The birds recently started chipping away at sandstone facings in the corner near MacLaurin Hall, built in the early years of the last century.

Staff in nearby offices were alerted by the noise of chunks of stone falling on to the roof of the cloister below. The University's facilities management office is keeping an eye on the situation, but Derek Hallam, assistant director of environment and heritage, is used to dealing with wildlife incursions. A recent survey found more than 80 species of flora and fauna living in the ecosystem around the University clocktower.

Mr Hallam said the birds were possibly attracted by the salts which leach through the stone in water and crystallise at the surface, causing the surface layer to break away.

But Dr Chris Dickman, a lecturer in biological sciences, said the birds were probably using the stone to sharpen their beaks rather than extract any nutritional value.

"Cockatoos need to maintain beak condition to ensure they are able to crack open their natural food including nuts," he said. "These animals may have discovered the University's stonework is ideal for beak-sharpening.

"Unfortunately, they are likely to come back and perhaps even tell their mates, so the stonework could end up being defaced unless the birds are persuaded to move."

Associate Professor Garry Cross, a bird health specialist in veterinary science, said he would be interested to see what seeds the birds were eating.

"In Africa and South America, psittacine birds eatfood that would be toxic were it not for their habit of eating clay off river banks immediately after ingesting the toxic seeds," he said.

"This presumably neutralises the ingested toxin, much like humans put cream on strawberries which neutralises the oxalic acid.

"But sulphur crested cockatoos also like to chew - perhaps these two are just passing the time while listening to lectures."

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