Building an aviary can be a fun job and depending on the size of your aviary it could also be a very big job too. Outdoor aviaries are great for larger birds or for people who enjoy have many birds nesting under the same roof. There are tricks to getting the aviary just right so that you are not interfering with other elements of nature. In places like some American states where bears can be a factor there are some general rules about keeping the feed and the birds separated. This is also true when snakes are involved and using a concrete base for the large bird aviary can make the snakes more visible even though deterring them all together can be very difficult.
Looking into the type of aviaries that a zoo might have to house it unique or even common native birds you can see that the modern zoos try to make these outdoor large bird aviaries as realistic to the birds natural habitat as possible. The stale and empty bird aviary is not pleasant to see much less for the birds having to live in them as for the people going to see the birds.
Segregation of some birds is often a necessity because of their territorial habits however you will find that most birds will get along just fine when put together in the same enclosure. Small flightless birds can be a good combination with other larger birds because the seeds and foods that fall to the floor are eaten by them. Make sure that any large birds of prey are not enclosed with any other species because often their instincts will lead to you finding only one bird left in the aviary.