Common Bulbuls time moult to the onset of rains in each locality

Most small birds replace their feathers (moult) annually because they need fresh feathers to fly and keep warm. Like breeding, moult takes place when birds can find enough food. Dr. Nwaogu and team found that Common Bulbuls moult specifically during the rains – a time when food is most abundant but can breed year-round despite lower food abundance in the dry season. This raised the question whether the timing of moult was influenced by rainfall or simply because Common Bulbuls moulted at a specific time each year everywhere. To answer this question, they measured the progress of moult in 15 localities across Nigeria where the rains start at different times each year and found that the progress of moult increased with earlier timing of the rains, confirming that moult is indeed influenced by rainfall and timed to the wet season in each locality.

To read more about this paper https://link.springer.com/article/10.1007/s10336-020-01825-1 and about the larger study http://hdl.handle.net/11370/30a7a470-9085-4e78-92e5-0da64a5a37e1