November 17, 2014
full story, video:
Evidence has been mounting for a while that birds and other animals can
count, particularly when the things being counted are items of food. But most of
the research is done under controlled conditions.
In a recent experiment with New Zealand robins, Alexis Garland and Jason Low at
Victoria University of Wellington tested the birds in a natural setting, giving
them no training and no rewards, and showed that they knew perfectly well when a
scientist had showed them two mealworms in a box, but then delivered only one.
The researchers reported the work this fall in the journal Behavioural
The experiment is intriguing to watch, partly because it looks like a child's
magic trick. The apparatus used is a wooden box that has a sliding drawer. After
clearly showing a robin that she was dropping two mealworms in a circular well
in the box, Dr. Garland would slide in the drawer. It covered the two worms with
an identical-looking circular well containing only one worm.
When the researcher moved away and the robin flew down and lifted off a
cover, it would find only one worm. The robins pecked intensely at the box,
behavior they didn't show if they found the two worms they were expecting.
Earlier experiments had also shown the birds to be good at counting, and Dr.
Garland said that one reason might be that they are inveterate thieves. Mates,
in particular, steal from one another's food caches, where they hide perishable
prey like worms or insects.
"If you've got a mate that steals 50 or more percent of your food," she said,
you'd better learn how to keep track of how many mealworms you've got.
The goal of research into abilities like counting is to get clues to how
thinking evolved. If birds and mammals can count, does this mean some kind of
mathematical ability goes back to a common ancestor before the dinosaurs? Or did
two separate paths lead to the same abilities?
While the New Zealand robins do seem able to count, they did not manage to
figure out how to remove the drawer and get the hidden mealworms.
If that happens, perhaps the robins themselves will be awarded Ph.D.s.