Rare Hawaiian Crow Shows Remarkable Tool-Making Skills

A rare crow species (the Hawaiian crow) has recently been observed to exhibit highly skilled tool-making abilities, according to the cover article of the September 15, 2016 issue of Nature. That article is titled “Discovery of Species-Wide Tool Use in the Hawaiian Crow.” The authors note that only a few bird species are known to use foraging tools in the wild. Perhaps the best known is the Caledonian crow (Corvus moneduloides), which has been recognized as a sophisticated tool-maker. The Hawaiian crow, called the ‘Alalā (C. hawaiiensis) became extinct in the wild in the early 2000s, but approximately 100 continue to live in captivity. Evidence that tool-making is part of the Hawaiian crow’s natural behavioral repertoire is two-fold: juveniles develop functional tool use without training or social input from adults, and proficient tool use is a species-wide capacity. Although both the New Caledonian crow and the Hawaiian crow evolved in similar environments on remote tropical islands, the two species are not closely related genetically, according to the researchers. Consequently, the scientists believe that the tool-making behaviors in the two crow species arose independently via convergent evolution. According to the researchers, convergent evolution supports the idea that avian foraging tool use is facilitated by ecological conditions typical of islands, such as reduced competition for embedded prey and low predation risk. The scientist write that their discovery creates “exciting opportunities for comparative research on multiple tool-using and non-tool-using corvid species. Such work will in turn pave the way for replicated cross-taxonomic comparisons with the primate lineage, enabling valuable insights into the evolutionary origins of tool-using behavior.” The authors are from the University of St.
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