A conservationist from Wales who has brought back at least nine species from the brink of extinction will receive a £170,000 ($250,000) prize later.
Prof Carl Jones, from Carmarthen, has saved birds including the pink pigeon and echo parakeet during 40 years of work in Mauritius.
He also expanded the number of Mauritius kestrels from just four in the wild to more than 300 in a decade.
Prof Jones will be awarded the 2016 Indianapolis Prize in London.
The man who nominated him for the award, Dr Simon N Stuart, chairman of the International Union for the Conservation of Nature (IUCN) Species Survival Commission, said: "I know of no other conservationist who has directly saved so many species from extinction."
Of the 63 bird, mammal and amphibian species worldwide that have been down-listed on the IUCN Red List as a result of conservation initiatives, Prof Jones has led the recovery efforts for six of them.
The cash prize and Lilly Medal will be presented to the professor, who is chief scientist of the Durrell Wildlife Conservation Trust and scientific director of the Mauritian Wildlife Foundation, at the Natural History Museum.
Prof Jones is known as a "Durrell disciple", having worked closely with author and naturalist Gerald Durrell since the 1970s.
He said: "It's a great accolade not just for me, but for Gerry Durrell and the people who have made this work possible over the years.
"I'm particularly proud of this award because it validates the conservation of animals — like Telfair's skinks and pink pigeons — that are not megavertebrates, but provide critically important ecosystem services nonetheless."