The average birder might not consider moult to be of much importance to them. Consider, though, that every time we look at a bird, we are seeing the consequences of moult. From how a bird looks to its ability to stay airborne, it is all dependent on moult. Without moult, birds could not transition from one plumage to another, they couldn’t maintain thermoregulation throughout the year, and they couldn’t replace feathers that would become so worn as to be useless for flight.
Lukas Jenni and Rafael Winkler’s 2020 Moult and Ageing of European Passerines (Brit. Birds 113: 304–305) looked at the consequences of moult for ageing. Their latest release takes things a step further, addressing the hows and whys of moult, its importance in a bird’s life and the biological processes that govern it – and are governed by it.
No prior knowledge of moult is required by the reader; section by section, you’re eased into the subject, from the form and function of the plumage to the biological process of moult, the (sometimes surprising) energetic trade-offs that are required, the long-lasting effects on the bird once active moult has ceased, and the strategies that birds use to fit moult into their annual cycles. The book is extremely well written, clear and avoids overly technical language, with summaries at the end of each section and each chapter emphasising the key points. That said, this is no slimmed-down overview of the topic – the authors, true masters of moult, have covered every aspect in great detail. I consider myself something of a moult enthusiast yet there was plenty here that was new and interesting for me.
It’s easy to recommend this book to anyone with an interest in moult; but I hope that the appeal will prove to be broader. Breeding, migration and moult are the three cornerstone events in most birds’ lives, and anyone who has read any of the many publications on the biology of the first two topics will surely enjoy ‘completing the set’ with this one too.