21 October 2013

Death by chocolate - Why human food poses a danger to clever kea

This blog post was written by postgraduate student Helene Rohl as part of the course, Research Methods in Ecology (Ecol608). Helene revisits a Lincoln University research area that look at the risks that waste has for kea published in 1998.

Kea are the only true mountain parrots in the world and are endemic to (only found in) the Southern Alps of New Zealand. Kea belong to the most intelligent bird group in the world, but sometimes their cleverness is counterproductive. 

Picture by anjuli_ayer
Some smart kea, for example, have learned to open the lids of rubbish bins to get to all the 'delicious' scraps we throw away. That this isn't healthy for them is probably obvious to every reader. But, what you may not know, is that people's favorite treat, chocolate, caused the death of an innocent, healthy kea at Aoraki/Mt Cook Village. Brett Gartrell from the New Zealand Wildlife Health Centre at Palmerston North and Chris Reid from the School of Biological Sciences at Wellington found this unfortunate fact during their examination of a dead kea and published their findings in the New Zealand Veterinary Journal in 2007. Chocolate, especially the dark variety used for cooking, contains natural toxins (theobromine, caffeine and theophylline) that can be lethal, if consumed in high doses. It seems that the 20 grams of chocolate that the adult male kea had eaten, was too much for the poor chap. Although this is the first reported case of a wild parrot dying due to chocolate consumption, the toxicity of chocolate to animals is not unknown. It has already been shown that chocolate can cause death in dogs.

Rubbish bins aren't the only human food source jeopardizing kea. Other curious kea prefer to explore the places where our scraps eventually end up: rubbish dumps. This sounds even more harmful compared to just one rubbish bin which is why Mark Jarrett investigated rubbush dump dangers for kea in his Master thesis at Lincoln University in 1998 . Mark discovered that some kea at the Arthur's Pass rubbish dump suffered from lead poisoning. The source of lead poisoning isn't necessarily the rubbish dump itself. It is more likely that the attractive source for lead poisoning are nail heads in huts or other building materials which are found outside of the rubbish tips. The rubbish dumps, concludes Mark Jarrett, may pose a threat to individual kea, but don't endanger whole kea populations, since only young and unexperienced kea get injured or die.


Picture by Brent Barrett
In fact, human food is a danger to kea in several ways: First, kea are mostly vegetarians, eating mainly roots, bulbs, leaves or fruits and occasionally some insects. But the human waste that they eat contains a lot of fat and sugar, doing the kea no good (as it does, by the way, to us humans, too!). Second, if young kea don't learn how to search for natural food (because they rely on our scraps) they may starve when they can't find something eatable in winter. Third, if leftovers or rubbish are easy accessible for kea, it may act as an invitation to explore the place, leading to more mischievous behaviour and risk of accident. 



Picture by Jem Copley
Another chapter of human and kea food associations is the feeding of wild kea, especially by tourists. Kea enchant the unknowing among us with their cheekiness and beauty. And before you can say 'tasty treat' tourists end up giving cookies to these clowns of the sky, ignoring happily the 'don't feed the kea' sign.





So for the future bear in mind: Keep kea away from chocolate! They aren't bird-brained at all, but human food does them no good.


Picture by Kiwihausen

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