Crows: Not your typical bird brain
When people think of intelligent animals, chimpanzees and dolphins come to mind. Widely regarded as nothing more than a pest, the crow is far more intelligent than it lets on.
Tool usage is one of the hallmarks of animal intelligence. While most animals in the wild learned of tools through trial and error, New Caledonian crows (Corvus moneduloides) seemingly understand the problem, and then look for specific tools for it. Two crows were captured from the wild and were tasked with novel problems. It was found that they would use tools that were just right for the job instead of just trying out any tool as most other animals do (Chappell & Kacelnik, 2002). It is thus not how they use the tool but what and how they were thinking when using a tool that makes them smart.
Furthermore, they seemingly understand the physical and functional properties of their tools, allowing them to make adjustments when needed (Hunt & Gray, 2002). The crows were given a metal wire with a hook to obtain a bucket of food. The first crow succeeded without much difficulty. However, the second crow was limited to a straight wire only. After trying unsuccessfully, it then created its own hook by bending the wire itself. It understands that it needed a hook to solve the problem and went on to create one (Weir et al., 2002).
All these cognitive abilities stems from their greater than proportionate brain to body size. They have larger associative and motor related areas in their forebrain which explains their impressive problem solving skills (Mehlhorn et al., 2004). They also showed brain lateralization, a trait which accounts for human intelligence that even chimpanzees do not have (Rutledge & Hunt, 2004). Perhaps bird brain may not be such an insult after all.
Chappell, J., & Kacelnik, A. (2002). Tool selectivity in a non-primate, the New Caledonian crow . Anim Cogn (2002) 5 , 71-72.
Hunt, G. R., & Gray, R. D. (2002). Diversification and cumulative evolution. The Royal Society , 867-874.
Mehlhorn, J., Hunt, G., Gray, R., Rehkämper, G., & Güntürkün, O. (2010). Tool-Making New Caledonian Crows Have Large Associative Brain Areas. Brain, Behavior and Evolution 75 , 63-64.
Rutledge, R., & Hunt, G. R. (2004). Lateralized tool use in wild New Caledonian crows. Animal Behavior 67 , 327-332.
Weir, A. A., Chappell, J., & Kacelnik, A. (2002). Shaping of Hooks in New Caledonian Crows. Science , 981.