To start with I would like to mention the exmoor beast a black leopard that is the main attraction at senior zoo
Southern aardwolf, tiger quoll, golden brush tail possum, rufous bettong, spinifex hopping mouse, dingo, Javan binturong, oncilla, Malayan tiger, johnstone’s Cassowary, white masked bearded palm civit, ringtail possum, yellow spotted bush hyrax and wombats at hamerton
There are a few missing from this list too. Greater Grison, Brush Turkey, Barking Owl, Black Backed Jackal(don't think anywhere else in the UK has them now) ?
Do you mean the animals with the smallest numbers in UK zoos or the animals with the smallest global populations that are held in UK zoos? If we think about the latter, I would suggest the Round Island boas at Jersey, the spoon-billed sandpipers at Slimbridge (neither of which are on-show) and Javan green magpies on-show at Chester and Newquay (not sure about the other holders).
What about the Southern helmeted curassow ( Pauxi unicornis ) at Lotherton Bird Garden - not the only keeper of this species in the UK but also the only keeper of this species in the whole of Europe.
@gentle lemur Jersey also has two pairs of JGM (one pair is on-show) Jersey zoo also holds the only black lion tamarin in Europe, half of which are on-show. Aye-ayes are not common in Europe with only one holder outside of the UK in Europe.
Other examples include flat-tailed tortoise and Anguillan racer at Jersey, ploughshare tortoise at Chester and Jersey, fanaloka and ringtail at Exmoor, Grandidier’s vontsira and white-tailed antsangy at Chester, Titicaca water frog at Slimbridge, Chester, BCA and Whipsnade, Lord Howe Island stick insect at Bristol, Bermuda killifish and Omani blind cave fish at Chester (and I believe the latter is also at Blue Planet Aquarium).....and so on
I'm just confused now! By global population, do we mean wild population or global zoo population or a mixture of both? If it's wild population the Amur Leopard or Bali Mynah have low numbers but are relatively common in zoos, even in the UK! As for the black leopards at Exmoor, they clearly don't fall into any of these categories, though they might be the only public collection in the UK to have them.
Correct, but some species were originally listed before clarification was given. The first few replies thought the question was about animals rarely seen in UK zoos, I think the black leopard example fuelled the misunderstanding!