In long-winged birds, where does the moult begin?

In long-winged birds, the moult typically begins at the fourth primary feather from the body. This pattern is part of a systematic process where the feathers are replaced in a specific sequence to ensure that the bird maintains its ability to fly effectively during the moult. Starting the moult at the fourth primary feather allows for a balance between maintaining necessary wing function and the gradual replacement of worn or damaged feathers.

The fourth primary feather is strategically chosen because it provides optimal surface area to facilitate ongoing flight and agility while the moult progresses. This sequence is crucial for long-winged birds, which need their wings to function optimally for hunting and migration. Feathers are essential for aerodynamics, and replacing them systematically helps to ensure that the overall wing structure remains effective throughout the moulting period.

In contrast, starting with feathers closest to the tail or at random could compromise the bird's flying ability, making it more vulnerable during this time. Such an organized moulting strategy minimizes the risk of predation and aids in maintaining fitness for flight.