For a long time I had noticed a strange absence of wild birds in the back of my house. The front of the house, facing the port, has plenty of seagulls, blue herons, and wild ducks. In the morning I wake up to quacking, cawing and arguing herons.
But the back of the house butts up to a mountain which is national forest and where you would think sparrows and bush warblers would live. If I walk in to the forest I can hear the birds, but they never came around my house.
As I love the sounds of birds, I used to play a CD of birds singing ("The Best of Song Birds — Unplugged, Live Soundtrack"). With the windows open and the bird chirps at high volume, the seagulls and herons flying by must have thought this was one heck of a big birdhouse. Not only that, but it would appear to them that the birds liked it so much here that they never went outside. A new breed of indoor birds.