Move over Milton Friedman, your feathers are about to be ruffled by a group of bird-brain economists.
In tests, 33 parrots from four different species surprised scientists with their shrewd profit-making ability.
The birds - macaws and African greys - were taught how to recognise the value of tokens that could be exchanged for food rewards.
They then had to make difficult decisions about whether to accept an immediate reward, or instead "invest" in tokens that guaranteed a more worthwhile return later.
High, low and medium value rewards were on offer - namely a piece of walnut, a nugget of dry corn, or a sunflower seed.
In a series of tests, the parrots consistently rejected disappointing immediate rewards and chose the token - but only if its value corresponded to higher quality food.
The results, published in the journal Scientific Reports, showed that the birds were capable of making "deliberate and profit-maximising decisions", said the German scientists.
Lead researcher Dr Auguste von Bayern, from the Max Planck Institute for Ornithology in Starnberg, said: "Given that wild parrots are so difficult to track, to date we know little about the ecological challenges most parrots encounter in their habitats in the wild, such as deciding where to go and how long to stay in a given feeding site.
"However, in our experimental setting we have found that they are capable of making surprisingly subtle decisions to maximise their payoff while minimising their effort.
"This is a fascinating indication that such decisions may matter greatly in their natural environment."
The hand-raised parrots, nine great green macaws, eight blue-throated macaws, eight blue-headed macaws, and eight African greys, performed as well as chimpanzees taking part in similar tests, said the scientists.
The experiment took place at the Max-Planck Comparative Cognition Research Station in Puerto de la Cruz, Tenerife, where the birds were housed in eight aviaries.
Among the parrots, the stand-out economists were the great green macaws, which made the right decisions significantly more often than would be expected by chance in every test.
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