Only a handful of bird species are known to use foraging tools in the wild. Amongst them, the New Caledonian crow (Corvus moneduloides) stands out with its sophisticated tool-making skills. Despite considerable speculation, the evolutionary origins of this species’ remarkable tool behaviour remain largely unknown, not least because no naturally tool-using congeners have yet been identified that would enable informative comparisons. Here we show that another tropical corvid, the ‘Alal? (C. hawaiiensis; Hawaiian crow), is a highly dexterous tool user. Although the ‘Alal? became extinct in the wild in the early 2000s, and currently survives only in captivity, at least two lines of evidence suggest that tool use is part of the species’ natural behavioural repertoire: juveniles develop functional tool use without training, or social input from adults; and proficient tool use is a species-wide capacity. ‘Alal? and New Caledonian crows evolved in similar environments on remote tropical islands, yet are only distantly related, suggesting that their technical abilities arose convergently. This 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.
In other words, crows evolve into woodpeckers when there are no woodpeckers. Sort of.
Here’s a video.
(Photograph from the original Nature article.)
In a related story, a recent study notes that Kauai, an Island of Hawaii, have lost a lot of birds due to climate change.
Eben Paxton, of the US Geological Survey’s Pacific Island Ecosystems Research Center in Hawaii, and his colleagues analysed data on seven native species of forest bird on Kauai. Between 2000 and 2012, populations of six of these … shrank by an average of 68% in their core range in the island’s interior, and by an average of 94% in the surrounding areas. Two of these species could be detected only in the interior region in 2012 surveys.
It appears that this is due to incrased temperatures that have helped spread bird malaria. At this rate, it is estimated, these birds will go extinct by mid century or so.
Greg Laden has been watching birds since they were still dinosaurs, but has remained the consummate amateur. This is probably because he needs better binoculars. Based in the Twin Cities, Minnesota, Greg is a biological anthropologist and Africanist, who writes and teaches about Evolution, especially of humans. He also blogs at Scienceblogs.com. Greg's beat is Bird Evolutionary Biology. One could say that knowing the science of birds can make the birds more interesting. But really, knowing about the birds that go with the science is more likely to make the science more interesting. And thus, birding and Neo Darwinian Theory go hand in hand. Darwin was, after all, a pretty serious birder. Greg has seen a bird eat a monkey in the wild.
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