The audacious life and revolutionary work of John Audubon

New York's Historical Society acquired the priceless water colours of John James Audubon 150 years ago. To celebrate, they are publishing a book showcasing the naturalist's groundbreaking work.

Audubon's The Birds of America series, published between 1827 and 1838, was a sensation in its day - purchased by royalty, statesmen and the leading libraries of Europe and North America.

The author of the new Audubon book and curator of the accompanying Historical Society exhibition, Roberta JM Olson, talked to the BBC's Michael Maher.