Endangered Hawaiian crow's newly discovered tool use 'of great significance'
A Hawaiian crow on the edge of extinction has joined the elite group of birds known to use tools.
Understanding the Alala crow's newly discovered talent could aid attempts to save the critically endangered bird, which only survives in captivity, scientists say.
Later this year, captive-reared Alala will be released in Hawaii in an attempt to re-establish a wild population.
Experts believe the bird's dexterous ability to winkle out insects and grubs from vegetation and dead wood using twigs held in its beak is natural behaviour, not something learned in captivity.
Only a handful of bird species are known to use tools, most notably New Caledonian crows.
Others include the woodpecker finch from the Galapagos islands, Egyptian vultures, and parrots.
British and US scientists tested 104 of the 109 surviving Alala crows and found that 78% of them spontaneously used stick tools to probe for food.
Lead researcher Dr Christian Rutz, from the University of St Andrews, said: " Current evidence strongly suggests that tool use is part of the species' natural behavioural repertoire, rather than being a quirk that arose in captivity.
"Using tools comes naturally to Alala. These birds had no specific training prior to our study, yet most of them were incredibly skilled at handling stick tools, and even swiftly extracted bait from demanding tasks.
"In many regards, the Alala is very similar to the New Caledonian crow, which my team has been studying for over 10 years."
The "corvid" crow family, which includes ravens, contains more than 40 species around the world, many living in remote locations and poorly studied, Dr Rutz added.
"This raises the intriguing possibility that there are some undiscovered tool users out there," he said.
The new findings are published in the journal Nature.
A population crash in the late 20th century wiped out the last Alalas in the wild.
In a last ditch effort to preserve the species, a small number of wild birds were brought into captivity and a breeding programme launched.
US co-author Bryce Masuda, from San Diego Zoo Institute for Conservation Research, a leading member of the team trying to save the Alala, said: " We had occasionally seen birds using stick tools at our two breeding facilities, but hadn't thought much of it ."
Douglas Myers, president and chief executive of San Diego Zoo Global, the non-profit organisation that operates San Diego Zoo, said: " The discovery that Alala naturally use tools is of great significance, especially at this critical stage of our recovery efforts, as it provides completely unexpected insights into the species' ecological needs.
"After more than 20 years of hard work, we are finally ready to release birds. I am confident we will manage to bring this iconic Hawaiian bird species back from the brink of extinction."