Yeah.... it does effect birds, more often the larger ones like crows and also especially raptors. We lost a pair of great horned owls two years ago to West Nile. One would hunt in the front yard and its mate would hunt in the back. I think the red-tail hawk population has been down because of it, but this winter we've had a pair of red-tails hanging around the lawn in front of the house. Maybe they're keeping our mouse population down, like the wild cat we have hunting in the back yard.