Speaking from my own experience I don't believe that birds are put off visiting gardens because of cats. Yesterday I counted six different cats pass through my garden during the day. The birds at feeders and elsewhere flew away and promptly returned when the cat/s had gone. But how do they know when to return, is one of them on sentry duty somewhere in the garden or is it down to luck
For years the only birds that visited were small, just lately two pair of Wood Pigeon come every day, could it because they are almost the same size as the cats they are acting as a deterent
Keep us updated.
John