WRONG. FACT CHECK
Domestic cats kill between 1.4 and 3.7 billion birds and between 6.9 and 20.7 billion mammals (mostly mice, shrews, rabbits, squirrels, and voles) each year, according to a study published last year in Nature Communications.

So according to science songbird sandwiches are not the cats favorite delicacy. Lol. BUT…

The greatest threat to birds is LOSS OF HABITAT. Yes your little slice of paradise multiplied reduces places where birds can eat, have protection from the elements and raise their young. Cats and all predators do what nature intended, strengthen the animal/avian population by eliminating the weak.