Here is a photographic overview of Prague to accompany the species list provided by
@EliasNys above. It shouldn't have too much outcome on the result with Prague already being far ahead, but hopefully, unless a strong rebuttal is made for Leipzig, which I haven't visited, it will convince more people to switch to a 4-1, and support my personal belief that Prague is one of the, if not the, best non-specialist zoos in the world for birds.
Going exhibit-by-exhibit, and being fairly comprehensive as possible but missing a few enclosures. One such miss that feels important to mention as it was also missing from EliasNys' list upthread: the free-flying bulbuls in the Indonesian Jungle.
Parrot Trail:
@Maguari
Consisting of nine really nice and spacious wooden aviaries for a pleasant selection of rarely kept lories and fig-parrots. The latter are especially noteworthy being from a family that strikes me as seriously underepresented at zoos. I love the authentic feel of the aviaries and the way that they incorporate the slope behind, as well as how surprisingly far back they stretch and the onshow indoor areas.
The row then culminates with a walkthrough for a further five species (not all parrots), of which Scaly-breasted Lorikeet and Bush Thick-knee are the most noteworthy. It was really nicely designed, but sadly I couldn't find any photos in the gallery.
Australia:
It also segués nicely into the next zone, Australia, where both Southern Cassowaries and Emus inhabit some rather run-of-the-mill enclosures, although of note is the onshow indoor area for cassowaries (haven't seen this elsewhere).
@Robaque - one of the two near-identical cassowary enclosures.
African Savannah:
@Chapman'szebra - home to Ostrich and one of the largest and most attractive savannahs at a city zoo in Europe.
Northern Forest:
@Maguari - one of the owl aviaries.
There are four owl aviaries here for three species, one of which being home to a major rarity, and one of the most curious-looking birds on the planet: the Oriental Bay-owl. I thought all three aviaries were really impressive, amongst the largest and most attractive I have seen.
There is also a much older cage, which held owls until recently but now houses some rescue European Honey-buzzards, incapable of flight. I think considering them not being flighted, it is a rather solid, and certainly very charming enclosure.
@Maguari - said Honey-buzzard aviary back when it held owls.
Aviaries Under The Cliff:
@Kalaw
For me, this is Prague's most underrated exhibit. Labelled on the map simply as 'storks' it is a huge aviary based around a spacious body of water (connected to a stream that runs throughout most of the lower zoo), and is notable for being really well-stocked with huge pelecaniformes, some of which (the Abdim's Storks and the rare Spot-billed Pelicans) took a liking to resting on the visitor railing. The mightily impressive weeping willows, and how far back behind the leaves of said trees it stretches for privacy, further strengthened the enclosure.
@lintworm
Although a little more generic in species list, the way that this Ibis walkthrough fades into the cliff was truly very impressive. Yet again, the number of big birds that it is really special to share a walkthrough space with, such as Yellow-billed Storks and Egyptian Vulture.
@Kalaw
Much more well-known than the previous two: the Great Aviary. One of the largest and best-landscaped bird of prey aviaries in Europe, really well-planted with a steep slope. While not necessarily a walkthrough, the main viewing gallery is open-fronted.
Also around here is the Bearded Vulture aviary, in some ways a scaled-down version of the Great Aviary above. I couldn't find any photos of it, though.
Bird Wetlands:
A simply wonderful series of aviaries for wetland birds, with the unfortunate caveat that some of them are pinioned. That said, the actual aviaries themselves, are both amazingly well-designed and home to a fascinating selection of species. Read EliasNys' list above for specific species.
The five aviaries consist of two walkthroughs, and are all geographically themed. They revolve around the Waterfowl Pavilion, which has several more aviaries on the other side, and presumably inside, but they are all offshow.
@Jana - view towards the aviaries showing their height. The building on the left is for Shoebills.
@Kalaw - one of the four aviaries, with this housing the Brazilian Mergansers.
@Jana - it's only fair to show the good and the bad. This meadow has several pinioned waterfowl, and sadly is not the only example of this at Prague.
Rakos' Pavilion:
Prague's other major avian offering. This advertises itself as a parrot house, but it really is a more general bird house, as each of the 9 aviaries features a parrot or two (the 'stars') but also several more co-inhabitants from the same region of the world. The geographical themes areas are stuck to really nicely. There are 2 outdoor aviaries (a huge one for Kea and a walkthrough) and seven indoor aviaries (two or three wire-fronted, two or three glass-fronted, and one walkthrough).
I'm not sure I have ever gotten so many lifeticks in one building since my first ever zoo visit. Again, EliasNys has very kindly provided a species list already, so there is no need for me to do so, but I will show just three of the most interesting exhibits.
@lintworm
For me, this huge walkthrough aviary is the highlight of the house, mainly due to how lively it is, and the presence of Monk Parakeets, one of only a handfull of parrot species that builds its own nests! There are many such nests in this aviary, doing remarkably well to put this behaviour on full display.
@lintworm
An upper-level view of the main indoor walkthrough aviary, which is rather spacious, very densely vegetated and landscaped, and yet still has a nice airy feel due to the natural sunlight seeping in.
@lintworm
A really nice highland New Guinea-themed (the walkthrough is lowland) aviary for a curious mix of Pesquet's Parrot and bird-of-paradise. The two species get along very well, and the aviary is far taller and deeper than this photo indicates, with the wire the icing on the cake.
Pheasantry:
The Pheasantry is a really extensive series of aviaries. For the smaller birds, such as laughingthrushes, they manage to be very good for the animals, while still keeping the undeniable charm of pheasantries (i.e. long rows of somewhat identical aviaries). That said, for the hornbills they are really poor.
@LaughingDove - for the most part, they look far less industrial than this as the vegetation has become a lot more dense in the decade since this photo was taken. But for the hornbills, I still believe it is too small.
The Pheasantry extends into a series of bird of prey aviaries, which are far better, and house a fascinating selection of species. Again, the list has already been provided, but I should reiterate the highlight: Pel's Fishing-owls, which have bred here for the first time in captivity.
@Chapman'szebra - for Egyptian and Hooded Vultures, rather good in my opinion.
Sichuan Pavilion:
Perhaps Prague's most beloved exhibit on this forum. Sichuan is noteworthy for being a glass-roofed, all-indoor walkthrough bird house that is
not for tropical species, but instead for those of temperate climates, from central China.
I've said in the past that I found Sichuan didn't quite live up to my high expectations, but that was purely because I found the vegetation to be a tad more tropical than I had hoped (there were some coniferous trees and ivy, but also palm trees and other clearly rainforest-based foliage) and that I was pressed for time. This gorgeous and quiet hall is a place that really benefits from spending time in there, soaking up the ambience and trying to spot all the birds.
@lintworm
@Kalaw - the newly built outdoor aviary attached to Sichuan. A really nice, elegant piece of modern architecture, with a nice water feature which creates 'stepping stones' in the visitor pathway.
Children's Zoo:
I didn't enter the Children's Zoo itself, so I'm not sure if there are more of these that I didn't find, but by good fortune, I found an aviary for a very interesting species, the Australian Magpie, at the edge of it.
But what most enthusiasts love the Children's Zoo so much for is 'Nature Around Us,' the zoo's native birds corner. There are three aviaries here, of which two are walkthrough and one is a very dense Little Owl aviary (essentially a single conifer that has been meshed off). I enjoyed these two aviaries, as native species areas are always a treat, and can result in some surprising realisations about how interesting your region's animals are; in this cause, it was the vibrance of a European Roller that caught my eye.
@lintworm - one of the two.
Penguin Pavilion:
Last but not least, we have the Humboldt Penguin enclosure. It seems very standard (other than its rather impressive size) at first, but upon further inspection one notes the presence of Fuegian Steamer Ducks. These amazing birds are flightless by nature, so enable the zoo to keep ducks in an open-topped penguin enclosure without having to pinion or clip them. A nice touch that I wish would become more common.
@Kalaw
That's all I could fit with the 20 photo-per-post limit, and don't really have the time to go over that.
I only just realised now that I missed out on the Darwin Crater aviaries, some of my favourite in the whole zoo, and there are so many other aviaries I had to leave out - a testament to how overwhelmingly good Prague is in this category.
Considering all the above, I have voted 5-0 Prague, if it is true that Leipzig's bird house is currently being emptied and they really do have so little. Prague has
242 species of bird onshow, and even more onshow. They have some of the absolute greatest bird aviaries in Europe, countless walkthroughs, breeding success with rarities (Pel's Fishing-owl, Brazilian Merganser, Salvadori's Fig-parrot), countless other scarcely held species, and some really tastefully designed aviaries throughout, used excellently to enhance other zones. The fact that Prague only has a rather small, but nicely done, bird house, in my opinion works to its advantage as there are so many at other intervals that can mix it up a little and add further interest to some parts of the zoo. The only real weaknesses are the occasional pinioned birds and the undersized hornbill aviares, but I just don't feel as though Leipzig has enough to capitalise on those weaknesses.
That said, I am very open to being persuaded that a 5-0 is too harsh if someone can provide an overview of what Leipzig has beyond the flamingo aviary (which, in fairness, does look very nice).