The four-volume, bound "Duke of Portland" set of 435 hand-colored engravings in excellent condition and more than 3 feet (1 meter) in height is considered one of the most prized books of ornithological art ever produced.

Francis Wahlgren, Christie's international head of books and manuscripts, said the $7.9 million sale was the third highest price for a printed book at auction.

"This strong result for Audubon's masterpiece confirms its iconic status and now holds the top three auction records for printed books," he added.

Christie's said the book was purchased by William Henry Cavendish Cavendish-Scott-Bentinck, the fourth Duke of Portland sometime after 1838.

"Audubon's masterpiece 'The Birds of America' is possibly the highest achievement in ornithological art today," according to Christie's.

Book experts estimate that the entire first edition consisted of just 200 completed copies produced during an 11-year period. Christie's said 120 complete sets are known to exist with 107 in institutions and 13 in private hands.

(Reporting by Patricia Reaney; Editing by Jill Serjeant)

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