After he left school, Durrell became a student keeper for the Whipsnade Zoo in England, and soon was given the job of traveling the world in search of specimens. His many books about this period in his life are filled with amazing and hilarious anecdotes. The work, he says, was extremely difficult but "could never, under any circumstances, be described as dull." However, Durrell did become bored with having to part with the animals once he had returned home. So Durrell decided that someday, somehow, he would have his own zoo.

Durrell had a second, more important reason for wanting to found a private zoo. In the course of many collecting trips to Africa and South America, Durrell had witnessed the loss of habitat and human depredation that was putting many animal species in danger of extinction. A private zoo would allow him to collect individual members of those animal populations and breed them in captivity.

When Durrell acquired Les Augres Manor on the Island of Jersey, he was finally able to realize his dream. The sole purpose of this sanctuary, which he called the Jersey Wildlife Preservation Trust, would be to collect specimens of endangered species for breeding. This would ensure that if a species were unfortunate enough to become extinct in the wild, there would be zoo-bred animals of the same species to replace them. In a personal epilogue to his book The Whispering Land Durrell explains his mission:

"All over the world the wildlife that I write about is in grave danger. It is being exterminated by what we call the progress of civilization. A great number of creatures will become extinct if something is not done, and done swiftly... Some time ago I created on the Island of Jersey a zoological park which is now the headquarters of the Jersey Wildlife Preservation Trust. Our aim is to create a sanctuary in which we can establish breeding colonies of these threatened species, so that, even if they become extinct in the wild state, they will not vanish forever."