| Citation | Christopher Perrins is distinguished for his important work on avian population ecology, in particular on reproductive rates. For the past 30 years he has been the principle architect of a long-term study of the population dynamics of the great tit at Wytham Wood, near Oxford, initiated in 1947 by David Lack. This unique continuous demographic record is the basis of one of the most famous of all studies in population ecology. Perrins' most important personal contributions within this study may be summarised as follows. (a) Heritability of clutch-size. In 1974, Perrins, together with his student P J Jones, demonstrated that clutch-size in great tits has a remarkably high heritability (approximately 0.7). This finding, which ran counter to theoretical prediction, has subsequently been confirmed in a number of other studies and has led to much debate about the mechanisms that maintain heritability of strongly selected traits. (b) Survival and fledging weight. Perrins was the first to demonstrate, in 1965, that within -year variation in juvenile survival can be traced back to nutritional state (reflected in fledging weight) in the nest. This finding had important implications for the interpretation of both population dynamics and the evolution of clutch-size. (c) Variation in clutch size. By a combination of analysis and long-term records and experimental manipulation of brood-size, Perrins and his co-workers Pettifor and McCleary showed that individual female tits lay a clutch appropriate to their ability to feed young; individuals optimise within their own constraints. (d) Timing of breeding. Perrins showed that great tits tend to breed later than would be optimal for raising young at the seasonal peak of food abundance. His nterpretation of this was that females are constrained by their build up of sufficient nutrient reserves to breed, an hypothesis that has received support in experimental manipulation of food supply. In addition to his own contributions, Perrins' long-term study has provided an opportunity for many students and post doctoral workers to make important discoveries in ecology and behaviour. |