The birds are renowned for their sophisticated tool-using ability, but until now, observing them in their natural habitat has proven difficult.
But specially designed "crow-cams" fitted to the birds' tails have shed light on the creatures, recording some tool-use never seen before.
The research is reported in the journal Science.
New Caledonian crows (Corvus moneduloides) are found on the South Pacific island of New Caledonia.
They can use their bills to whittle twigs and leaves into bug-grabbing implements; some believe their tool-use is so advanced that it rivals that of some primates.