Kea with lead poisoning
Other than slight weight loss noted by the Department of Conservation’s monitoring report, Andrew showed no other obvious clinical signs of lead poisoning. Symptoms of heavy metal poisoning in birds can include:
fluffed up feathers
lack of appetite
vomiting and/or regurgitation
green watery droppings
and, in severe cases sudden death (Bird Vet Melbourne, n.d.; Burwood Bird & Animal Hospital, n.d.).
Andrew was radiographed to ensure that the source of his lead poisoning wasn’t internal and from something he had consumed. His radiographs showed no signs of lead. In his natural environment, Andrew may have come into contact with lead by chewing or licking lead head nails, old lead paint and lead flashing on huts, sheds and/or houses. He could have also come into contact with lead at rubbish dumps, from car wheel weights, lead shot and bullets. Unfortunately, when Andrew and other kea find a source of lead they chew on it because it’s soft and it tastes sweet. Even when a bird doesn’t present with clinical signs of lead poisoning, elevated blood lead levels can result in poor reproduction, starvation, and early death due to predation or misadventure (Department of Conservation, n.d.).
Andrew began his first round of chelation therapy on the evening of 11 August 2016. He was prescribed 0.2ml Edetate Calcium Disodium (Calcium EDTA) given intramuscularly into his pectoral muscles twice daily for five days. Chelating agents like Calcium EDTA bind to toxic metal ions allowing the lead to be excreted in urine (Flora & Pachauri, 2010). Each Calcium EDTA injection was supported with oral fluids to help Andrew’s kidneys excrete the lead and to help prevent kidney damage. Andrew received 20ml Hartmann’s solution/compound sodium lactate with 1.25ml 40% dextrose added with each chelation treatment. The fluids were warmed in a water bath to 38°C and administered via a metal crop tube.
After Andrew’s initial five-day treatment, his blood was retested two days after his final treatment. The results showed that his blood lead level had dropped to 0.15mg/L. He was given five days off for his kidneys to recover and then his second round of chelation therapy began. The aim was to get his blood lead level under 0.05mg/L. His second round of treatment finished on the morning of 26 August 2016 and his subsequent blood test showed his blood lead level was under 0.05mg/L. He was released in Arthur’s Pass National Park on 3 September 2016.
Admission date: 11 August 2016
Release date: 3 September 2016
Species: Nestor notabilis / parrot
Breed: New Zealand kea
Kea are the world’s only alpine parrot. They are endemic to New Zealand and they are only found in the South Island’s alpine environment. Despite their high visibility in our National Parks and alpine environments they are nationally endangered with population estimates of only between 1,000-5,000 birds (Department of Conservation, n.d.).
Age: Juvenile, under 3-4 years
Reason for admission
In response to Arthur’s Pass kea having died from lead poisoning in early 2016, the Kea Conservation Trust tested the blood lead levels of 5 Arthur’s Pass kea including our patient named Andrew. Andrew was found to have very high lead levels, 0.634 mg/L. Currently accepted safe blood lead levels for birds are 0.05 mg/L.
Nursing considerations during hospitalisation
While treating Andrew there were several nursing considerations we had to be mindful of. One of the biggest concerns was that Andrew would learn to associate us and other humans with food. Kea learning that humans are a source of food is one of the main ways they come into conflict with humans, and it is one of the leading causes of their population decline. Human food is also for the most part quite toxic and/or too high in sugar for kea. This meant that with each feed (morning and evening) we had to remove Andrew from his cage, secure him in a smaller cage and place him in the consultation room while we prepared his food and water, and cleaned his cage. We would then return him to his cage where the food and water had “magically” been replenished!
Another important consideration was getting the balance right between enrichment feeding and allowing Andrew to easily access his food as he was still an ill bird. As kea are highly intelligent it was important to provide environmental enrichment so that he didn’t become bored and develop stereotypies like body rocking. Often Andrew’s food was used to provide enrichment and food was placed in numerous items like pine cones, containers, card board tubes, children’s toys and boxes. Sometimes this meant that he could easily access his food and sometimes subsequent cage cleaning and weighing Andrew’s remaining food showed that he wasn’t necessarily able to access all the available food. This was something we had to monitor very closely to ensure that he wasn’t missing out on essential calories.
As with most of the birds receiving treatment at the Wildlife Hospital, it was also important to keep ourselves relatively quiet and calm. This meant that we didn’t spend time talking or playing with Andrew. This is probably one of the hardest parts of working with our wildlife as it’s very natural to want to offer comfort and support by talking to our patients.
Bird Vet Melbourne (n.d.). Heavy metal poisoning. Retrieved September 20, 2016 from http://www.birdvetmelbourne.com/heavy-metal-poisoning/
Burwood Bird & Animal Hospital (n.d.). Heavy metal poisoning in birds. Retrieved September 20, 2016 from http://www.bird-vet.com/heavyMetalPoisoninginBirds.aspx
Department of Conservation (n.d.). Kea. Retrieved September 12, 2016 from http://www.doc.govt.nz/kea
Department of Conservation (n.d.). New Zealand Wildlife Diseases. Retrieved September 12, 2016 from http://www.doc.govt.nz/wildlifediseases
Flora, S. J. S., & Pachauri, V. (2010). Chelation in metal intoxication. Retrieved September 30, 2016 from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2922724/