Lee the kakapo. Photo: Auckland Zoo.

After being successfully treated for lead poisoning at Auckland Zoo, Lee, a male kakapo died following a three-hour emergency operation.

A post-mortem examination has confirmed that Lee died from a small tear in the side of his crop - the sac-like part of the bird's digestive system where food is stored before it enters the stomach. This tear caused food to escape into the surrounding tissues, resulting in severe inflammation. Vets also discovered several areas of thinning in the crop wall, which they say could have predisposed Lee, an older bird of unknown age, to this type of injury.

"A tear in the crop is the equivalent of a stomach rupture in a human with the resulting, and often fatal, peritonitis," says the zoo's New Zealand Centre for Conservation Medicine (NZCCM) senior vet, Dr Richard Jakob-Hoff. "While working to repair this injury, Lee's heart stopped twice, but we managed to resuscitate him. However, he went into cardiac arrest again at the end of the procedure, and this time we were unable to bring him back - the shock on his system just too great."

He said that Lee, a founder kakapo who could be up to 100 years old, appeared to be in good shape, was behaving normally, and continuing to put on weight. However, shortly afterwards he deteriorated and did not digest any of the food from his last feed.

Emaciated

"When he arrived, Lee was emaciated, weighing just 1.2kg, and his survival was seriously in doubt, so gaining body weight was critical if he was going to pull through. Experience shows wild-caught adult kakapo do not readily adapt to eating in captivity, so tube feeding (using a special parrot formula) was the only way to provide adequate nutrition. Over a two-month period, Lee successfully put on half a kilogram, and was ready to be returned to Codfish Island. Tragically, we had no warning signs of this tear to his crop, as all his test results were healthy," says Dr Jakob-Hoff.

Crop feeding - 21 kakapo

The Department of Conservation says crop feeding has been used with great success over the years to nurture kakapo back to health. DOC's technical supporter officer for the Kakapo Recovery Team, Daryl Eason, says since 2001, 21 kakapo have been crop fed and three were fed for periods of two and eight months. He says without such feeding, it is highly unlikely they would be alive today.

"Age seems to be the main difference between these latter three birds and Lee - they were all juveniles, whereas Lee was potentially a very old bird," says Mr Eason.

Ageing population

"This highlights the inevitable - that we're going to see an increase in age-related deaths in kakapo. Forty-six per cent of the current population are of unknown age (at least 27 years) - these are the founding birds transferred from Stewart Island to the safety of Codfish or Little Barrier islands in the 1980s. "Over the coming decades these birds will be reaching the end of their lifespan, so we expect to see the population stay relatively stable, as older birds die and are replaced with young. The health of the population will however, continue to improve as this age structure shifts," says Mr Eason.

"All of this reaffirms that the kakapo population is still very vulnerable, and that the intense management programme we are running is critical to the survival of this species."

Second kakapo being treated

Dr Jakob-Hoff says that the zoo's vet team has also been treating a female kakapo, Sarah, who was flown from Codfish Island to Auckland Zoo on Tuesday 21 October. Sarah, another founder kakapo from Stewart Island, is being treated for a wound to the side of her cloaca (possibly caused by injuring herself on a sharp stick) and subsequent weight loss.

"We had used a soft tube on Lee, but as a precaution for Sarah we will use an even softer tube. However, this is a fine balance, as too soft a tube can also cause problems by folding on to itself," says Dr Jakob-Hoff.

About the kakapo - 90 left alive

• The critically endangered kakapo is the rarest parrot species in the world.
• Total population: 90 on two islands - Codfish Island (Whenua hou) off the north west coast of Stewart Island, and Anchor Island in Dusky Sound, Fiordland.
• Kakapo live many decades. How long is uncertain, but mortality figures indicate that the average life span is 90 years.
• Most original founders from Stewart Island, still living, were found as adults between 1980 and 1989. The last remaining Fiordland male was found in 1975, at the time an adult of unknown age.
• There are 44 female and 46 male kakapo. 20 females and 22 males originate from Stewart Island, and one male comes from Fiordland. The rest have been produced on sanctuary islands, primarily since 1997. No other kakapo is known to survive in their original habitat, due to predation by cats, stoats and rats.
• Breeding: The kakapo population reached an all-time low of 51 birds in 1995. Earlier this year (2008) six chicks were produced from five nests on Codfish Island, a very minor breeding season.

Large breeding season predicted

A large breeding season is anticipated next year on Codfish Island as a result of a very heavy crop of rimu fruit presently forming on the trees. Breeding seasons in successive years is a very unusual event. The last large breeding season was in 2002, when 24 chicks were produced.