Over the years, pigeons have often not been viewed as among the smartest of birds, and the overall intelligence of birds has generally been rated below that of primates, such as monkeys.
In the 1990s, rhesus monkeys were trained by scientists to look at groups of items on a screen and rank them from the lowest number of items to the highest.
"Our research not only shows that pigeons are also members of this exclusive club, but, somewhat surprisingly, their performance is on a par with that of monkeys."
A paper outlining the research has just been published in Science, a leading science publication, and when the embargo on publication was lifted early yesterday, the pigeon story featured on the New York Times online edition.
And recently Dr Scarf's phone has been running hot as he has fielded calls from reporters in many parts of the world, including from the Discovery Channel, Scientific American, and New Scientist, as well as journalists from Japan and Sweden.
"It's the idea that pigeons can do something as well as monkeys. I think that hooked them," he said.
"It's amazing. Seriously, its very humbling to have this much interest.
"Usually, I'm just plodding away in the laboratory," he said.
The Otago researchers initially trained the pigeons by presenting them with 35 sets of three images, each with one, two, or three objects of different sizes, colours and shapes.
They were rewarded with wheat when they pecked the images in the correct ascending sequence.
Next, the researchers sought to test if the pigeons could take what they had learnt from ordering the three images and apply it to images with higher numbers of objects than they had seen before.
"While this is obviously a long way away from how humans can count, it shows that an animal with a brain structured quite differently to ours is still able to perform complex mental tasks of which only humans were once thought capable."
He next plans to test keas and other parrot species housed at the Dunedin Botanic Garden aviary.