Moult
In the Common Nighthawk all bodily plumage and rectrices are replaced in the post-juvenile moult. Post-juvenile moult commences in September at the breeding grounds; majority of the body plumage is replaced but wing-coverts and rectrices are not completed until January–February, once the bird arrives at the wintering grounds. There is no other moult prior to the annual moult of the adult. The Common Nighthawk adults have a complete moult that occurs mostly or completely on wintering grounds and is not ceased until January or February.
Read more about this topic: Common Nighthawk