The Newcastle woman reported that within a week of the pecking incident she experienced pain, swelling and redness near the injury site.

Doctors at the Calvary Mater Newcastle treated her with antibiotics and anti-fungal drugs. But after 16 days in hospital the woman developed gangrene and the next day surgeons amputated her left leg above the knee.

The offending bird was a magpie her daughter had kept as a pet.

Infectious-diseases physician Paul Wilson presented the details of the case in the latest edition of The Medical Journal of Australia.

Dr Wilson said the case was ''particularly unusual''.

''Firstly, by the mechanism of injury:people getting infections after being pecked by birds isn't very common to begin with,'' he said. ''And, secondly, the actual organism was an uncommon one that doesn't cause human infections very often.''

A biopsy revealed that a fungus called Saksenaea vasiformis, an uncommon human pathogen, caused the infection.

Dr Wilson wrote that an infection of this kind was first observed in 1977 in a young man who had sustained a severe skull trauma in a motor vehicle accident.

A total of 29 cases of human infection arising from the action of this fungus had since been reported in English-language medical literature.

Dr Wilson said the infection in the magpie case might have been less severe had the woman not been a former smoker and had pre-existing circulation problems.

''She might not have needed amputation had her circulation been OK to begin with,'' he said.

In his paper, Dr Wilson referred to other, more serious infections relating to trauma involving birds, including septic arthritis of the knee after a chicken bite and a fatal brain abscess caused by a rooster peck.

But Dr Wilson said infections caused by bird peckings were rare.

''I don't think the general public needs to be too worried,'' he said.