Why Molt?

[BuffaloParrot]

Most birds shed their feathers and grow new ones regularly because:

1. Feathers wear out and new ones are needed to replace them.

2. Old feathers might be infested with parasites.

3. Plumage may be changed to suit the season, with winter plumage often being dull or cryptically colored to fool predators, and breeding plumage more colorful to attract females and deter competing males. 

[wishforabird]

that's right, the guys need new threads to impress the ladies!!