A temporary export ban has been placed on two albums of drawings, watercolours and lithographs by ornithologist John Gould which have been valued at more than £1.2 million.
The Department for Digital, Culture, Media and Sport (DCMS) said the 129 images are at risk of leaving the country if a UK buyer is not found for the 19th century works.
The albums contains pictures of birds from around the world, some of which are now extinct.
The albums also contain images by his wife Elizabeth Gould and the artist Henry Constantine.
The export ban, imposed by the DCMS, is to allow time for a UK institution or gallery to come forward and purchase the albums to prevent them being sold overseas.
Culture minister Caroline Dinenage said: “These exquisite drawings provide an important insight into the work of one of our most significant ornithologists, helping us to better understand 19th century study of natural history.
“I sincerely hope that these beautiful works can be saved for the nation so they may continue to inform our knowledge and understanding of John Gould’s brilliant work.”
The export ban was placed on the object following advice from the Reviewing Committee on the Export of Works of Art and Objects of Cultural Interest.
Committee member Peter Barber said: “There is much still to be discovered, bibliographically, but particularly from the standpoint of the history of science, about these often beautiful but above all honest drawings, by one of this country’s greatest ever ornithologists and his talented wife.
“The drawings sometimes differ in important details from the artistic lithographs derived from them, but they are perhaps most significant as being amongst the earliest accurate depictions of non-European birds, some now extinct.
“They should be retained in this country so that they can be researched not only from an artistic and bibliographical perspective but above all in the context of Gould’s correspondence and the specimens, also gathered by John Gould, held by British institutions.”
A decision on whether the albums can be exported has been deferred until September 24. However, this may be extended until January 24 if a party has a serious intention to raise the funds to buy it for the recommended price of £1,287,500.