LONDON — It’s quite a nest egg. John James Audubon’s “Birds of America,” a rare blend of art, natural history and craftsmanship, fetched more than $10 million at auction on Tuesday, making it the world’s most expensive published book.

With its 435 hand-colored illustrations of birds drawn to size, the volume is one of the best preserved editions of Audubon’s 19th-century masterpiece. The sale at Sotheby’s auction house had been anticipated for months by wealthy collectors.

The book sold for $10,270,000 to an anonymous collector bidding by telephone, the auction house said.

Because each picture is so valuable, there have been fears the volume will be broken up and sold as separate works of art. However, experts believe that’s unlikely.

“Audubon’s ‘Birds’ holds a special place in the rare book market,” said Heather O’Donnell, a specialist with Bauman Rare Books in New York.

“The book is a major original contribution to the study of natural history in the New World.”