An illustration from Audubon's The Birds of America, 1827-1838, which is to be auctioned in London in December. (Sotheby's/ Associated Press)

A rare first edition of John James Audubon's The Birds of America is expected to sell for more than $6 million at a London auction of rare books this December.

Also on auction is a Shakespeare First Folio valued at $1.8 million and rose drawings from the hand of naturalist Pierre-Joseph Redouté, which could sell for $1.5 million.

All are from the collection of Baron Frederick Hesketh, a collector of rare books who died in 1955. The sale, set for Dec. 7, is on behalf of Hesketh's estate.

The Shakespeare First Folio, considered one of the most important books in English history, dates from 1623 and has 451 of the original 454 leaves. It contains complete text to 36 plays.

The folio is the first collection of the playwright's work, and was published at the request of his friends after Shakespeare's death in 1616.

The first-edition Audubon is expected to draw a higher price because of its size and the quality of the paintings the naturalist made of American birds.

Audubon wanted to paint the birds life-sized, and the book measures 90 by 60 cms to accommodate the prints.

"That's all very well with weed warblers, but when you come to bald eagles, you're going to need a big book," said Sotheby's rare books expert David Goldthorpe said. "Audubon himself described the size as a 'double elephant' folio."

There only 119 copies of the first Audubon remaining and most are in museums and libraries. He sold the books by subscription in a period from 1827 to 1838.

This copy was originally owned by paleobotanist Henry Witham who bought it after a personal meeting with Audubon in 1826, Sotheby's said.

A copy of Birds of America was sold by Christie's for $8.8 million in 2000, setting a record for a printed book at auction.

Hesketh's wide-ranging collection also contains:

• Polychronicon, by William Caxton, the man who brought the first printing press to Britain.
• Facta et dicta memorabilia, an early printed work by Valerius Maximus.
• Lives of Romulus and Cato the Young, by Plutarch, an illuminated manuscript.
• 40 letters related to the imprisonment of Mary Queen of Scots.

Goldthorpe said Hesketh acquired his books in the "golden age of collecting."

"Unlike other libraries which specifically focus on, for instance, literature, history or science, the 50 lots coming from this magnificent collection are an example of what is known as 'high spot collecting' — when a collector seeks out the very best across a range of fields," he said.

With files from The Associated Press