This is kind of off-topic but birds can be pretty advanced in surprising ways. In particular, birdsongs can be pretty complex and some species have evolved spec

This is kind of off-topic but birds can be pretty advanced in surprising ways. In particular, birdsongs can be pretty complex and some species have evolved specific cognitive functions for understanding, replicating, and producing birdsongs. It is conceivable that features evolved in relation to some tasks may also enhance behavior in other cognitive tasks. I would not be surprised if quite a few species besides crows perform just as well for the task mentioned in the article, and others. Here is a neat review relating to songbirds: http://languagelog.ldc.upenn.edu/nll/?p=3261 http://languagelog.ldc.upenn.edu/nll/?p=3261