Strategy of Falconidae

Falcons:  initiate the moult at primary p4 (sometimes p5) and replace the feathers neatly towards both ends: one towards p1 and the other towards p10 which will be the last primary to be replaced. Once some primaries are replaced, the moult of the secondaries starts but this time at the most inner secondary (numbering depending on the size of the species) and s5. From s5 the moult proceeds towards both ends: one towards the most inner secondary (meeting with the moult coming from this direction), and the other one towards s1 which will be the last secondary to be replaced.

 

Patirrojo
Photo (Joan Goy) taken from the book: AVES RAPACES DE EUROPA (Ollé and Trabalon, Omega 2019).