Possible Clues:

• The bird in the clock
• It lays eggs in the nests of others
• Bird only makes appearance at certain times
• Crazy; bird
• Local crazy person draws attention to time in Switzerland perhaps
• Bird in a clock
• It's a strange bird who only makes an appearance at certain times
• It takes over other birds' nests
• Bird that pops out of a clock
• Bird who makes hourly appearances?