We live in a high rise in a very big desert city (albeit by the ocean). This is not exactly like our home in Denver with very tall trees and lots of squirrels and birds. Back in Denver our cats stayed inside and the birds were outside and it worked just fine. Now that we have a balcony many floors above the street, the cats spend time relaxing on the deck chairs outside and get the opportunity to get fresh air and soak up the sun.
A week or so ago Lucy added to the adventure by trapping a bird (some kind of local dove) on the balcony. The poor animal saw our patio plants and must of thought they were trees. Lucy batted it down and a scuffle ensued on the balcony. Richard was able to rescue the bird but Lucy had learned to be alert to the wildlife.
A few days later I came down to make the morning coffee and saw bird feathers all over the living room floor. I was sure that Lucy had taken down another bird and consumed it in the house. I spent the next hour hunting for a carcass but to no avail. It was Sunday so we settled in to read the Sunday paper - the local Lima paper which is actually quite good. Suddenly there was a flutter of wings and a bird flew down from on top of the china cabinet and Richard was once again called to be the savior and let the poor bird out through a window. Apparently it had flown inside, probably escaping Lucy, the previous day when we had left the patio door open for a short time.
So - we know now that we would have visitors if we placed a bird feeder outside. More importantly we know that would be a really bad idea since our killer cat would be after them. We apparently still have our wild kingdom in the "back yard".