There is a trend in zoos to provide more naturalistic enclosures for animals in which they can carry out natural behaviours and, for most birds, an aviary presents the best opportunities to achieve this. Reasons for holding birds in aviaries, including education and visitor experience, breeding, behaviour, predation, veterinary issues, avoidance of invasive species and hybridization, welfare and enrichment, and reductions in costs, are discussed. The development of the Aviary Database Project is explained. This information-sharing resource is in development and will be a tool for exchanging knowledge and experiences in designing and constructing aviaries, and selecting the best aviary for the species in question and for the geographic location. Zoos may be able to avoid expensive mistakes and optimize their possibilities by sharing information on aspects such as costs, visitor viewing, suitable materials and design features. By lowering the barriers in the way of building appropriate aviaries, it is hoped that this type of housing will become the option of choice in future master plans. While adopting an aviary strategy for housing all ‘flying’ birds may result in a reduction in the number of species at a zoo, and could affect both institutional and regional collection plans, we believe it is a necessary step in order to provide the optimal conditions for the care and well-being of the birds that are already in zoological institutions.