As long as their are no local ordinances against bird feeding, the neighbor can legally feed the birds. But they should do so with regard to their neighbors. It sounds like the feeding stations are attracting large numbers of birds. I'd recommend asking your neighbor if they would reduce the number of feeders and or the amount of food they are putting out. The weather has been mild this year and the birds can find plenty of food on their own. Enjoying seeing birds at the feeder is good. But hopefully the neighbor will understand that the number of birds is causing inconvenience and concern to the other neighbors. To help ease your concern about health issues, to be a health hazard there would have to be very large amounts of bird excrement. Simply washing with hot, soapy water will work to clean affected areas. Homes and decks can be cleaned with a hose or power washer. The long-term solution is to reduce the number of birds congregating in one place. Hopefully everyone can reach a happy compromise.
