Posted: 21 Apr 2010 07:51 AM PDT
It's not just that some birds can use tools, as primates can. Their smarts stretch even further: New research this week suggests that New Caledonian crows can solve a three-step problem, in which the three steps must be completed in succession to reach a tasty snack. Alex Taylor and colleagues document this discovery in the Proceedings of the Royal Society B.
Here's the setup: There's a short stick dangling from the bird's perch on a string. That short stick isn't long enough to grab the food that's tucked inside a long and narrow box, but there's a longer stick in a separate box. If the birds could figure out the first two steps---grabbing the short stick, and using it to get the longer stick---then voila, they could use the longer stick to reach the food.
The team split the birds into two groups. The birds in group number one got to mess around with each step of the process individually before researchers presented them with the problem as a whole. Coauthor Russell Gray says, "All these birds had to do was to put together things they could already do in the right sequence" [BBC News]. And they did: Each solved the problem on its first try.
Group two faced a tougher task, Taylor says. "These crows had never pulled up a tool on a string before and they had never used one tool to get another tool," he says. Instead, he says, they used their previous
experiences of pulling up a string and using a long tool to get food to innovate a new behaviour [Australian Broadcasting Corporation]. Thus, it took the group two birds a little longer to crack the puzzle---sometimes
multiple attempts. But in the end they all succeeded as well. In the video above, a bird named Sam figures it out.
The genius of crows comes as no surprise. A feature article in DISCOVER's March issue, "Who You Callin' 'Bird Brain?'," documented the mind-blowing mental abilities of crows and other members of the corvid
family. For example, British researcher Nicky Clayton's scrub jays appeared to sense when they were being watched by competitors, and thus would return to their hidden caches of food and move them around in an
attempt to thwart would-be thieves.
The researchers in the three-tool study have already seen New Caledonian crows whittle branches into tools, and a stream of other finds has shown that birds recognize themselves in the mirror, or, in a confirmation of
an Aesop fable, use rocks to raise water level. The American preacher Henry Ward Beecher said that if men "bore black feathers, few would be clever enough to be crows". Certainly, in a parliament of fowls, they
would rule any roost [The Guardian].
