Book excerpt: The moult strategies of birds are not only of importance in their impact on a species' ecology and energetics, but as a valuable tool for anyone studying the migration and population dynamics of bird species. A proper understanding of how feathers are replaced, and the precise differences in appearance of the various feather generations, can allow ringers, scientists and the keen birdwatcher to age first-year and adult birds and to detect the moult strategy of the bird in question. Lukas Jenni and Raffael Winkler have combined these themes and produced a book which will be valuable both to the professional ornithologist and the bird ringer. The first part gives an up to date summary of the moult strategies and moult sequences of European passerines and discusses the ecological consequences of moult. Throughout the book, the authors draw on the enormous amount of data on moult collected by them over 15 years of study which, combined with data from the literature, allow them to present a new synthesis of the subject. The second part of the book is of particular value to ringers. Following a general introduction to ageing, detailed moult profiles are given for 58 species of European passerines representing all the major moult strategies, backed up with useful summary statistics, schematic diagrams of the extent of moult and indications of the variation within each species. For the first time, the extent of partial and suspended moults is presented in detail. The crowning feature of this book is the 480 plus full colour photographs of extended wings which show the entire range of moult patterns and of plumage ageing criteria. An appendix gives supplementary information on ageing birds by the degree of pneumatization of the skull.