One thing I would hope to see if/when an aviary expansion comes is the ability to keep the current habitat animals within aviaries as well. This would have several uses:
1) It could allow the construction of more realistic netted or roofed enclosures for animals such as primates and some of the big cats (snow and clouded leopards particularly); certainly in the case of the clouded leopard I have never seen them kept in an outdoor enclosure that isn't covered over with a mesh roof.
2) Certainly here in Europe there is an increasing trend in making aviaries for birds previously kept in open-air enclosures, particularly flamingos (Chester Zoo have recently opened their new covered flamingo aviary); this is both for welfare reasons (taking out the need to clip or pinion the birds) and biosecurity (now that bird flu is endemic in Europe, aviaries take away the need to shut away birds during outbreaks). This example from Gaiazoo in the Netherlands shows one example of a new flamingo aviary:
Source: https://www.youtube.com/watch?v=Qn5vRBTCQhI
3) Perhaps most relevant, there is an increasing fashion in Europe to create large outdoor aviaries that combine free-flying birds with enclosures for large mammals. These are some examples:
- At Doue-la-Fontaine in France, their Okapi Sanctuary is an aviary housing okapis, owl-faced guenons and nineteen species of bird: the picture here shows the okapi with goliath heron, African openbill stork, hamerkop, sacred ibis, Egyptian goose, crested guineafowl and Abdim's stork, but it also includes hooded vultures, African grey parrots, great blue turacos, three species of pigeon and trumpeter hornbill:
- Also at Doue-la-Fontaine, this picture shows part of an enclosure that used to be for giant anteaters (I believe now replaced with armadillos) within Europe's largest aviary, which also contains four species of macaw (you can see a green-winged macaw on top of the cliff), three other parrot species, flamingos, Peruvian pelicans, Andean condors, turkey vultures, nine species of duck and goose, roseate spoonbills, three species of ibis, boat-billed herons, black-necked stilts, Southern screamers, inca terns and grey gulls, with further enclosures within the aviary for pudu and Humboldt penguins:
- At Antwerp Zoo in Belgium, there is an aviary mixing African buffalo with twenty-three bird species; as well as the Abdim's storks, cattle egrets, African spoonbills and glossy ibises in this photo, there are also two species of vulture, two species of turaco, superb starlings, three species of pigeon, two of hornbill, lilac-breasted rollers and various other species of ibis, duck, lapwing, guineafowl, spurfowl and hamerkop:
- Zooparc de Beauval in France has a colossal aviary that encompasses enclosures for hippos, nyala and red river hogs, as well as birds. This view of the hippo area includes pink-backed pelicans, yellow-billed storks, a white-headed duck and a palm-nut vulture, with a view of the nyala section on the right-hand side:
- This better view of the nyala section in the same aviary shows African openbill stork, African spoonbill, sacred and Southern bald ibises, grey crowned cranes, blue-winged geese and hamerkop:
Being able to do this would be another way of making interesting new enclosures for some of the animals already in the game.