Clever crow naturally uses tools
A bird so rare that it is now extinct in the wild has joined a clever animal elite; the Hawaiian crow naturally uses tools to reach food.
The bird now joins just one other corvid - the New Caledonian Crow - in this exclusive evolutionary niche.
Dr Christian Rutz from St Andrews University, described his realisation that the bird might be an undiscovered tool-user as a "eureka moment". He and his international team of colleagues have published their discovery in the journal Nature.
Crow footage courtesy of San Diego Zoo Global and St Andrews University
Video produced by Victoria Gill