Washington: Pigeons may not be so bird-brained after all, as scientists have found they are as capable as primates when it comes to understand numbers.
Psychologists at the University of Otago in New Zealand found that pigeons have brilliant mathematical competence and can decipher between different amounts of number-like objects and order pairs.
This is stunning because it's trait that has only been shown in primates. Past studies have shown that various animals, from honeybees to chimpanzees, can learn to count when trained with food rewards.
In the new study, published in the journal Science, the researchers were also able to teach pigeons abstract rules about mathematics.
"Pigeons are the perfect subjects for visual tasks, because their vision is really good and they're really easy to train," Damian Scarf, first author of the study said.
"It appears that you can train them on almost any task you can train monkeys on."
For their study, Scarf and his colleagues first trained three pigeons to count up to three. On a touchscreen, they presented the pigeons with a set of images that had objects of various sizes, shapes and colours.
For example, one set presented images with one yellow block, two red cylinders or three yellow rectangles. To receive a treat, the pigeons had to select the images in the correct object-number order, from lowest to highest.
Once the birds learned to count to three, the researchers began showing the pigeons images with up to nine objects. On average, without higher-number training or food rewards, the pigeons were able to correctly order the image sets over 70 percent of the time.
The pigeons had an easier time discriminating between lower numbers and numbers that were further apart.
"Once you start getting up towards seven, eight and nine, it was very difficult for [the pigeons] to tell the difference between the images," Scarf said.

Overall, the results of the study echoed those of the rhesus monkey research, though Scarf noted it took longer to train the pigeons than other researchers took training monkeys, he added.
William Roberts, a psychologist at University of Western Ontario who was not involved in the research, was surprised by the study's results.
"I didn't anticipate that pigeons could have done that," said Roberts, who has previously researched animal cognition, including pigeon intelligence.
Roberts is curious to see how widespread this ability is in the animal kingdom. "Can we find evidence for this type of counting in insects, particularly bees?" he said.
Finding the same level of numerical competence as the pigeons (and rhesus monkeys) in other species would help scientists understand if the ability evolved across species separately, or if a common ancestor shared the ability, said Scarf, who plans similar experiments on parrots and other birds.