The Grants published the results of their long-term study of the evolution of the two species of finches—fortis and scandens—in Science in April 2002 under the title “Unpredictable Evolution in a 30-Year Study of Darwin’s Finches.”8 Before starting their research, they had hypothesized that the body traits of the finches would vary within a narrow band over the period of the study. But as they say at the beginning of the article, “The data do not support the expectation of no change.”
