There is a very good quote about John James Audubon by his granddaughter Maria:
"Waiting times are long, longest to those who do not understand the silent, inner growth which goes on and on, yet makes no outward sign for months and even years, as in the case of Audubon."
Audubon trudged into his 30s doing stuff he wasn't all that interested in (mismanaging a few businesses, which landed him in jail for debt [he had a wife and two kids on the outside at the time--hardcore]). But in the back of his mind an idea was forming, which ultimately manifested itself in an ambition to capture in vibrant colors, fluid lines, and at life-size the likenesses of all the birds in the United States. When he announced his intention to realize this he must have seemed to others suddenly mad, but in fact the idea had long been in development. And fortunately for Audubon, not to mention all who enjoy his wonderful art, it all worked out.
His story reminds me of evolutionary theory, where you have gradualism (the slow change of organisms over time), and punctuated equilibrium (wherein we see a rapid rate of morphological change over a short period of time). Punctuated equilibrium is often associated with cataclysms--a meteor hits the earth, kills the dinosaurs, and suddenly a whole bunch of niches (think of them as job positions) open up, which are rapidly filled by other critters (giant birds, giant sloths, giant mammoths, other giants) that rise to the occasion.
So for years Audubon was a gradualist, and as such his mind was slowly evolving towards his goal. But after spending time in jail I suspect he entered his period of punctuated equilibrium (i.e., "I've got to make some changes fast"). Gradualistic thinking had prepared him to seize the opportunity that punctuated equilibrium thrust upon him.
One Audubon biography I read stated (and I have to paraphrase, since the book is not accessible to me in my motel room ;-D) that Audubon was not certain what he would do after his release from jail--but the one thing he knew was that he was through with business. As he returned penniless to a wife and two children, everything we know and love Audubon for today lay ahead of the then-34-year-old man.