Biology graduate student Vanya Rohwer and his co-authors reveal why larger birds take longer to replace their flight feathers.
Many birds depend on flight to survive and therefore must replace their flight feathers regularly. Feather replacement (molt) typically requires a long period of time and is therefore an important event in a bird’s life. Recent research by S. Rohwer and colleges shows that the rate at which feathers grow is less than the summed length of flight feathers. Therefore large birds that have long feathers take disproportionately more time to replace their flight feathers than smaller birds. This relation between feather growth rate and feather length provides one of the first general explanations for why larger birds cannot replace all their feathers in a single season, and helps explain why many large species of birds have different strategies of replacing their flight feathers. Rohwer's paper is published in PlosBiol.