I can see the logic, but only 117 examples at taginfo suggests that this tagging is the exception than the rule.
However, given that what we have right now isn’t really working, I suspect a bit of “gardening” of values would make sense (and I’m sure that could be done while avoiding bear traps like “historic” above).
On the topic of aviaries, the Wiki has clear instructions that an aviary in a zoo is to be tagged zoo=aviary and a “standalone” aviary (not in a zoo) is to be tagged tourism=zoo zoo=aviary. This is in contrast to bigger bird parks, which are to be tagged tourism=zoo zoo=birds.
a zoo is an institution while an aviary is an object, the wiki is just wrong and the example of the historic, unused aviary demonstrates it. This was never a zoo, so even disused zoo would not represent it well.
I mean I agree with you, an aviary isn’t a zoo. And when I am looking for zoos, I probably don’t want to be shown aviaries.
But the Wiki has said, for seven years, that when someone sees an aviary, they are supposed to tag it as tourism=zoo zoo=aviary, and that’s what people seem to have done. So now the Wiki just documents current tagging
So if we want to “garden” this we’d need to garden both the Wiki and the data…
Are there other similar features we might wish to include, aquariums have been mentioned, any others? Or would that be a bad idea, should the proposal focus on one small issue at a time?
Looking at objects tagged tourism=zoo, aviary is the smallest “zoo type” by far. The second smallest type is zoo=butterfly. (Overpass) I’m not familiar with them so I can’t judge if it’s accurate to describe them as zoos.
There is also zoo=enclosure, this is, according to the Wiki, both used for whole zoos and for invidual enclosures, not in a zoo. An example would be this one where wild boars are kept in the middle of a forest (OSM). I wouldn’t really call that a zoo, and as the history of the object shows, I am not the only one. It could make sense to also discourage this specific use of the tag?