April 21, 2010
Tool-Using, Problem-Solving Crows Surprise Scientists
Recently-published research completed by scientists at the University of Auckland in New Zealand proves that New Caledonia crows can use multiple tools to solve problems and complete tasks.
The crows, scientific name of Corvus moneduloides, live in the South Pacific island of New Caledonia and are the only species of birds that have been observed making and using tools into the wild. The scientists further studied their skills in a laboratory setting and discovered that they can use up to three different tools in succession to overcome obstacles and obtain food.
The New Caledonia crows, which have been observed whittling branches into hooks and using leaves to help obtain food from small or hard-to-access areas, were given "a novel three-stage metatool problem" by the researchers, according to the abstract accompanying their paper.
"The task involved three distinct stages: (i) obtaining a short stick by pulling up a string, (ii) using the short stick as a metatool to extract a long stick from a toolbox, and finally (iii) using the long stick to extract food from a hole," they wrote. "Crows with previous experience of the behaviours in stages 1"“3 linked them into a novel sequence to solve the problem on the first trial. Crows with experience of only using string and tools to access food also successfully solved the problem."
"This innovative use of established behaviours in novel contexts was not based on resurgence, chaining and conditional reinforcement," the psychology professors continued. "Instead, the performance was consistent with the transfer of an abstract, causal rule: "Ëout-of-reach objects can be accessed using a tool'. This suggests that high innovation rates in the wild may reflect complex cognitive abilities that supplement basic learning mechanisms."
Seven wild crows were split into two groups for the task. The first group was allowed to examine each part of the task before being presented with the entire multi-step problem. The second group was not familiar with all steps of the challenge before being asked to come up with a solution and obtain the food. All three birds in the first group were successful on their first try, according to the BBC, and the four in the second group were able to solve the problem within four attempts.
"Finding that the crows could solve the problem even when they had to innovate two behaviours was incredibly surprising," Taylor, the lead author of the paper, told Morelle.
Corvus moneduloides is approximately 15 inches long and is said to resemble a more slender looking version of the house crow. It has glossy black colored feathers, as well as black beaks, feet, and legs. They are found in the forests of island of New Caledonia and the Loyalty Islands and typically dine on nuts, seeds, insects, and other invertebrates.
On the Net:
New Caledonian Crow - http://en.wikipedia.org/wiki/New_Caledonian_Crow
University of Auckland - http://www.auckland.ac.nz/uoa/
Proceedings of the Royal Society B - http://rspb.royalsocietypublishing.org/