After examining the advantages, disadvantages, risks, and limitations of most commercially available bird deterrent systems, this article focuses on two technologies most generally applicable to historic buildings: plastic netting and nonelectrified tensioned wire. Guidance for selecting, specifying, contracting, and supervising bird deterrence projects follows. The author presents a model bird deterrent installation at the Department of Agriculture headquarters building in downtown Washington, DC as a case study. Model specifications for removing bird excrement and bird-repellent gel from buildings appear as appendices. -- AATA