Give your cat an egg once see what happens.
But I can change my statement abit and talk about the flightless baby birds. If the eggs are taken, the adult birds may try and lay more if enough time is left in their breeding season, once the eggs have hatched and the young are killed few bird species will make another attempt at reproducing that season. Ofcourse that doesn't include the bunnies of the bird world such as sparrows/starlings etc.
Cats With Bells on Their Collars Do Kill Birds: Studies have shown that bells on collars are not effective in preventing cats from killing birds or other wildlife. Birds do not necessarily associate the sound of a bell with danger, and cats with bells can learn to silently stalk their prey. Bells offer no protection for helpless nestlings and fledglings - - - From the same study done by the University of Wisconsin