Even so, evidence is mounting of a sixth extinction -- this time caused by human actions. To keep up my spirits when I was tired and things seemed extra-bleak, I made a collection of what I call my "symbols of hope." Many illustrate the resilience of nature -- such as a leaf from a tree found in Australia, previously known only from fossil imprints on rocks. A tree that has survived seventeen ice ages and is still alive and well in a hidden canyon in the Blue Mountains. A feather from a peregrine falcon that was flying again in an area where it had been locally extinct for a hundred years and another from a California condor, a species rescued from the brink of extinction. This was what caught Thane's attention when I was lecturing at the zoo in Cincinnati. He said I should write up those stories. I told him I intended to -- but there was so little time. He said he would help. Thane is a kindred spirit. He, too, is filled with optimism for our future. Clearly this is a very different book from the slender volume originally planned. I kept meeting amazing people who had done amazing work to prevent animals from becoming extinct. And I met them all over the world. How could I write about the California condor and not the whooping crane? And what about the giant panda, symbol of conservation?
Then, somehow, word got out that we were writing this book and information flooded in -- why were we not including insects? Amphibians? Reptiles? And surely the plant kingdom was important, too?
And so the book grew, not only in volume, but also in concept. It seemed so important to discuss some of the species believed extinct that have been rediscovered -- sometimes more than a hundred years after they had been written off. And to write about the wonderful work being done to restore and protect habitats. I found that people got really excited about the idea of sharing the good news, shining a light on all the projects, large and small, that together are gradually healing some of the harm we have inflicted. It has been several years in the making, this book, and it has taken me on a fantastic journey of exploration: I have learned ever more about animal and plant species brought to the brink of extinction by human activities and then -- sometimes at the very last minute and against all odds -- been given a reprieve. The stories shared here illustrate the resilience of nature, and the persistence and determination of the men and women who fight -- sometimes for decades -- to save the last survivors of a species, refusing to give up.