The New Zealand parrots that attack your wing mirror when you are driving in the mountains are keas. Their relatives are the kakapo and the kaka, both endangered. Here, a study has established the adaptive nature of North Island kaka to novel and familiar stimuli. Any New Zealand parrot is welcome to my wing mirror but the kaka is Nestor meridionalis, which flies free on the mainland at a few sanctuaries such as Zealandia Ecosanctuary, established in 2002. They fly high in forest canopies, sometimes with some kea, which are less arboreal. Their ability to innovate is the specific part of cognitive development studied by Julia Loepelt, Rachael C. Shaw and Kevin C. Burns in this study. They work at the Victoria University of Wellington, near the mainland sanctuary.
104 Nestor meridionalis were tested overall in problem solving tasks involving a feeder and a very unfamiliar piece of apparatus. Ages ranged from 4 months to a not-so-aged 13 years, but only 24 of these parrots had the patience to carry out all 3 tasks. Kaka are classed as adult after 4 years and 35 of the subjects were in this category. Neophobia is the fear of new objects and also seems to have a place in kaka behaviour, as the research confirmed. The problems confronting the animals were problem solving, exploratory strategy and persistence, all on an individual basis.
The kaka population in the large (225 hectare) sanctuary is 350-400 and were new to cognitive testing. However, they have been banded as nestlings since their reintroduction to Zealandia, and later fitted with RFID tags, leaving the researchers with useful age and ID data. The feeders used in the experiments were familiar to the kaka, as were the cashew nuts they contained! Naive kaka were carefully recorded at each trial, to assess if they used social learning by watching others achieve the desired rewards.
1. For block-removal, the kaka had a novel problem in which they had to remove the wooden block by pulling or pushing. They could then us their familiar tread plate to obtain cashews. This had the lowest success rate for the birds
2. Another novel foraging problem was created to test neophobia in Problem 1. Instead of tread plates, the individual birds had to simply flip open the familiar feeder lid.
3. String pulling was entirely novel to the birds. A 50cm green string had to be pulled upward to gain the cashew nut reward. This experiment in fact had the highest success rate.
Juveniles were the best performers, with no adults able to solve the block-removal task (Problem 1) and only one solving the lid-opening (Problem 2.) The juveniles were also the faster working and more persistent of the subjects and showed greater exploratory diversity (in string-puling and lid-opening.) For example, they pulled out the block within 4 trials, whereas sub-adults took at least 10 "goes." You can guess that the adults couldn't do this at all.
If any other kaka were present on the test platform or a branch, the outcome was not affected in Problems 1 and 2. That indicates no social effect, but watching another subject pull the string in Problem 3 id make other kaka more successful. Go figure that one!
Other birds also show this juvenile bias towards success in problem solving. This is the first time it has been shown in any parrot and also indicates that decreased behavioural flexibility prevents adults from being innovative. Neophobia did not seem to be involved.
The diversity of exploratory behaviour correlates with success, as it does in other birds and even hyena. If you like, it is creativity that wins, while adults tended to use force. Julia and her fellow researchers tend to the view that the adults failed to modify the learned response to the feeders, although juveniles had received less reinforcement of this learned behaviour and therefore had less history to overcome. Excuses, excuses! At least the under-performing adults had success in the string-pulling.
Our thanks go out to these researchers, not only for the photography from them, but the efficient product and the ideas they convey on animal thinking and how conservation needs to deal with animals in habitats that don't exactly match their own. You can read the whole paper,from the Proceedings of the Royal Society B,under the title of
Can you teach an old parrot new tricks? Cognitive development in wild kaka(Nestor meridionalis.) > Comparisons of parrot intelligence (their common ancestor lived >80 million years ago if you consider the isolation of New Zealand) stretches to the apes in this story.