The natural inquisitiveness of keas, combined with the sweet taste of some lead-based products, is endangering its health and population numbers.

Dr Jenny Youl, a veterinarian in the University’s New Zealand Wildlife Health Centre in Palmerston North, has discovered high levels of lead in the population of wild keas living around Mt Cook.

Dr Youl’s preliminary results from research undertaken in collaboration with the Department of Conservation and behavioural researchers from Victoria University, indicate that at least seven of 10 dead wild kea from the Mt Cook area died from toxic levels of lead in their body.

Dr Youl says that 16 of the 18 samples from live wild keas had lead levels greater than the allowable level in humans (0.1mg/l). Two of the birds sampled had levels high enough to cause serious disease and death.

She says lead is ubiquitous throughout the New Zealand environment due to its presence in construction materials, shot, petrol, paints and batteries. It can also be sweet tasting and may be sought out by animals feeding in a contaminated area. She says the particularly inquisitive and destructive nature of kea and the fact that they learn through manipulation of objects has lead to incidences of ingestion of foreign substances. Likely sources for kea are lead head nails and lead flashing on old huts and homes.

She says lead toxicity in potentially declining populations of birds such as kea may have detrimental population effects, and its effect at even low levels can be detrimental. While higher levels of lead can cause obvious clinical signs like vomiting and ataxia, lower chronic levels are known to cause a reduction in intelligence and learning ability. Even once exposure stops, lead may be stored in bones, which is a risk for laying females using their bones to form egg shell.

Massey vets will continue working with the Department of Conservation to collect samples to determine the extent of the problem in the Mt Cook area and other populations of kea in the South Island.

Local conservation staff in the area have been working to identify the source of lead and produce a plan to reduce exposure, and this information will be used to reduce lead exposure in other kea areas.