1. 1. Lande, R. & Arnold, S. J. Evolution 37, 1210–1226 (1983). 2. Endler, J. A. Natural Selection in the Wild (Princeton University Press, 1986). 3. Grant, P. R. Ecology and Evolution of Darwin's Finches (Princeton University Press, 1986). 4. Boag, P. T. Evolution 37, 877–894 (1983). 5. Grant, P. R. & Boag, P. T. Auk 97, 227–244 (1980). 6. Grant, P. R. Am. Orn. Un. Monogr. 36, 471–483 (1985). 7. Grant, P. R., Grant, B. R, Smith, J. N. M, Abbott, I. J. & Abbott, L. K. Proc. natn. Acad. Scl U.S.A. 73, 257–261 (1976). 8. Boag, P. T. & Grant, P. R. Science 214, 82–85 (1981). 9. Price, T. D., Grant, P. R, Gibbs, H. L. & Boag, P. T. Nature 309, 787–789 (1984). 10. Gibbs, H. L., Grant, P. R. & Weiland, J. Auk 101, 872–874 (1984). 11. Gibbs, H. L. & Grant, P. R. Ecology 68 (in the press). 12. Cane, M. A. Science 222, 1189–1195 (1983). 13. Price, T. D. Ecology 68 (in the press). 14. Grant, P. R. Anim. Behav. 29, 785–793 (1981). 15. Boag, P. T. & Grant, P. R. Biol. J. Linn. Soc. Lond. 22, 243–287 (1984). 16. Price, T. D. & Grant, P. R. Evolution 38, 483–494 (1984). 17. Fleischer, R. C. & Johnston, R. F. Nature 298, 747–749 (1982). 18. Price, T. D. Am. Nat 123, 500–518 (1984). 19. Grant, B. R. Evolution 39, 523–532 (1985). 20. Monaghan, P. & Metcalfe, P. Evolution 40, 1096–1099 (1986). 21. Schluter, D. & Smith, J. N. M. Evolution 40, 221–231 (1986). 22. Grant, P. R. & Price, T. D. Am. Zoo/. 21, 795–811 (1981).