Like the title says, you have to free the bird. To do that you should point and click right places and do right things.
Good Luck!!!

Play Free The Bird

Walkthrough:
Change the clock by pulling on the 4 strings in the back to match the clock on your computer. When done, click on the the lever right of the clock to make the cuckoo bird in the clock pop out. The lever on the left controls the position of the cuckoo bird. Left long, left short, right long, and right short are the 4 position. (Not in order). One of the positions will do something to the string holding the parrot up. When you do it sufficiently, you will drop the cage. FREEDOM! (By the way, if the clock on your computer advances to the next minute, the cuckoo will stop popping out and you will have to re-adjust. Best not to play when your computer is at 59 minutes, you will have to re-adjust 59 times to get it back around.)

Online Games point-and-click walkthrough