The Notorious Nestor notabilis: Conservation of the Clever Kea

Hiking the Edwards-Hawdon Route in Arthur’s Pass National Park a few weeks ago, I had my first encounter with the majestic, yet devious, kea (Nestor notabilis). While stopping to catch my breath, a curious kea hopped over to greet me. I was thrilled to see this beautiful bird for the first time; I admired its verdant, olive coloring and laughed at its inquisitive gesticulations. After taking a 100 (mostly blurry) pictures, I continued on my hike. Little did I know I would meet the kea again.

After living off nuts and fruit for two days, I looked forward to a piping-hot basket of salty fries at Arthur’s Pass Cafe. As a US-native, I knew nothing of the kea’s notorious nature, nor that they terrorize tourists throughout the South Island, particularly those with food. I was no exception. Though I only narrowly escaped the kea’s attempted fry-heist, my interest in the bird blossomed.

The misfortune for the kea began during the 20th century. Populations sharply declined due to farmers’ mass bounty-hunting, followed by stoat (Mustela erminea) and possum (Trichosurus vulpecula) predation and, to make matters worse, the initiation of stoat and possum poison bait which kea have been known to eat. With increasing habitat pressure, human conflict, and accidental poisonings, kea have been listed as nationally endangered. The latest kea census was taken at the end of March with alarming results; the female kea population has plummeted.

Why is kea conservation so important? Well, these local hooligans are full of cheeky chicanery, and are the world’s only alpine parrot. Until recently, however, little research has explored their cognitive capacities. Recent literature is in strong agreement that kea are not just erudite for avians but intellectually on par with elephants and chimpanzees. But how and why did these playful parrots get so smart?

Research suggests that during the Pleistocene glacial climates kea had relatively low food abundance, which spurred their cognitive evolution. Through this glacial period, kea became extremely opportunistic feeders with a diverse diet; and nowadays these birds exhibit no neophobia towards novel foods. The evolutionary history and curios nature of the kea has resulted in an above-average  brain-to-body mass ratio evidencing their advanced cognitive development and behavioral flexibility.

Kea at Mount Aspiring National Park (Copyright Lorena Singer, Taken March, 2017).

In addition to their foraging history, much research shows that the complexity of the kea social structure is correlated to their intelligence. One study tested kea in their understanding of cooperation, behavioral flexibility and patience. Kea were the first non-human animals shown to wait more than a minute for a partner with whom they were cooperating. More impressively, one kea in this study clearly demonstrated a preference for problem-solving with a partner when faced with a complex contraption filled with food. Kea are the first bird species to perform at a similar level to chimpanzees and elephants in a variety of collaborative tasks. Collaboration was imperative for human evolution and our current societies, therefore, the kea’s preference for collaboration has piqued researchers’ interest. Patience is seemingly a cross-species virtue.

Kea are also great problem solvers. When assessed for their understanding of causal relationships, the kea aced the test! Tested with a widely-used technique of string-pulling to access food, the inquisitive nature of kea and rigorous destructiveness came in handy. Of the 19 birds, six birds were immediately able to figure out how to pull the string, while four showed mostly efficient, rather than exploratory actions. Kea demonstrated behavioral flexibility throughout the tests and used a variety of problem-solving techniques. Kea also managed to solve complex technical tasks through identifying that certain techniques would result in the desired outcome (i.e. food dispensed). This means that they could identify the properties and uses of certain objects; that is toddler-level cognition!

There is so much more to learn about these wily parrots, but first action must be taken to conserve kea populations. A prominent bird conservation issue in New Zealand revolves around the is the use of pellets containing the poison 1080 for possum control. This is a heated debate as there are two pressing issues: (1) kea dying from invasive species predation, and (2) kea dying from invasive species control methods, as kea regularly eat 1080 pellets or scavenge animals that have done so.

Kea food-color preference testing at the Willowbank Wildlife Reserve and Orana Wildlife Park. (Copyright James Ross 2012).

Back in 2012 researchers investigated kea food color preferences using dyed-cake pieces to avoid further 1080 poisoning. Carolin Weser and James Ross found that green was disliked most by kea; however, there were still instances where the green dyed-cake was consumed. Since then research has looked at a plethora of possibilities to deter kea from eating 1080 baits such as infusing cinnamon or garlic in bait, which are also known kea deterrents.

Many argue that the use of 1080 should be stopped, as kea have suffered from poisonings. However, a recently-released five-year study about the kea’s cousin, the kaka, found that 30 times more chicks were produced where 1080 was used, resulting in a 55% nesting success rate up to a year after 1080 treatment, versus only 1.75% success rate where the compound was not used. The bottom line is that 1080 is currently the best available eradication method for stoats and possums, who are the primary predators of kea.

Thus, researchers have started to explore how to accommodate, and take advantage of kea cognitive capacities. I interviewed Dr. James Ross in April 2017 about the 1080 pellet color research. He explained recent exploration of lacing dummy pellets with substances that make kea nauseous to teach avoidance. This would integrate knowledge about kea social learning and adaptive abilities. Subsequently, the 1080 pellets could be dropped with much less danger to the kea. Much is left to explore in this regard but from recent research on kea social structure and learning until 1080 can be replaced with more mammal-specific poisons and delivery methods.

Kea at Mount Hutt, Canterbury (Copyright Bernard Spragg).

Though the body of kea research continues to grow, the dark cloud continues to hang over conservationists: Is enough being done to save these playful parrots from rapid decline? It is a race against the clock, and scientists must continue to research the keas’ conservation needs; despite their notorious reputation, they are the emerald jewel of New Zealand’s mountains. These birds exist nowhere else in the world and there are very few animals, let alone birds, that express such high cognitive abilities. They are truly a species worth saving.


Works Cited:

Eason, C., Miller, A., Ogilvie, S., & Fairweather, A. (2011). An updated review of the toxicology and ecotoxicology of sodium fluoroacetate (1080) in relation to its use as a pest control tool in New Zealand. New Zealand Journal of Ecology, 1-20.

Heaney, M., Gray, R. D., & Taylor, A. H. (2017). Kea show no evidence of inequity aversion. Royal Society Open Science, 4(3), 160461.

Heaney, M., Gray, R. D., & Taylor, A. H. (2017). Keas Perform Similarly to Chimpanzees and Elephants when Solving Collaborative Tasks. PloS one12(2), e0169799.

Huber, Ludwig, Sabine Rechberger, and Michael Taborsky. “Social learning affects object exploration and manipulation in keas, Nestor notabilis.” Animal Behaviour 62.5 (2001): 945-954.

O’Hara, M., Schwing, R., Federspiel, I., Gajdon, G. K., & Huber, L. (2016). Reasoning by exclusion in the kea (Nestor notabilis). Animal cognition19(5), 965-975.

Robertson, H. A., Dowding, J. E., Elliott, G. P., Hitchmough, R. A., Miskelly, C. M., O’Donnell, C. F., … & Taylor, G. A. (2013). Conservation status of New Zealand birds, 2012. New Zealand threat classification series, 4, 22.

Ross, J. (2017, April 24). Kea Bait Color Research Review [Personal interview].

van Klink, P & Crowell, M. (March 2015). Kea (Nestor notabilis) survivorship through a 1080 operation using cereal baits containing the bird repellent d-pulegone at Otira, central Westland. DOC Research and Development series 344. Retrieved on June 5th, 2017 from

Werdenich, D., & Huber, L. (2006). A case of quick problem solving in birds: string pulling in keas, Nestor notabilis. Animal Behaviour, 71(4), 855-863.

The author Sophia Winkler-Schor is a postgraduate student in the Master of International Nature Conservation taught at Lincoln University and University of Göttingen. She wrote this article as part of her assessment for ECOL 608 Research Methods in Ecology.

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