Jersey wins this hands down due to one of their dominant focus being on insular endemic fauna across the world (Madagascar, the Caribbean, Mauritius and the Indian Ocean islands), their collection comprising animals from these regions (and others such as the islands of South-East Asia and the Galapagos) and their enormous ongoing efforts to conserve threatened species in these ecosystems.
Jersey zoo / Durrell trust
Madagascar
Malagasy fauna kept at zoo :
Mammals - Aye-aye, ring tailed lemur, Alaotran gentle lemur, black and white ruffed lemur, red ruffed lemur, red fronted brown lemur, Malagasy giant jumping rat (first zoo to breed species and bring into ex-situ), Mayotte brown lemur, narrow striped mongoose, greater hedgehog tenrec, lesser hedgehog tenrec.
Birds - Madagascan pochard, Madagascar teal, Meller's duck, hammerkop, Malagasy ibis, Madagascar fody, Malagasy turtle dove, .
Reptiles - Ploughshare tortoise, Madagascan flat tailed tortoise, radiated tortoise, panther chameleon, Malagasy ground boa, Madagascan big headed turtle.
Amphibians - Golden mantella.
Current Malagasy in-situ conservation projects by Durrell trust - Madagascan pochard project, Madagascan side necked turtle project, ploughshare tortoise project.
Past in-situ conservation projects by Durrell trust (Largest programe country of trust) - Kirindy forest reserve project (Narrow striped mongoose and Malagasy giant jumping rat ), Lake Alaotra project (gentle lemurs, Meller's duck, Malagasy pochard), Project Angonoka (ploughshare tortoise).
Caribbean
Caribbean fauna currently and formely kept at zoo
Mammals : 0
Birds : Montserrat oriole, St Lucia amazon parrot, St Vincent amazon parrot.
Reptiles: Lesser Antillean iguana, rhinoceros iguana, Haitian galliwasp,Hispaniolan slider, Jamaican boa.
Amphibians : Mountain chicken frog.
Current Caribbean in-situ conservation projects by Durrell trust: Mountain chicken project, Antiguan racer, Saint Lucia racer, Saint Lucia whiptail lizard.
Past in-situ conservation projects by Durrell trust : Montserrat oriole project, St Vincent parrot, St Lucia parrot.
Mauritius and Indian Ocean Islands
Mauritian (and island) species currently and formerely kept at zoo:
Mammals: Rodrigues fruit bat (first bred ex-situ by Durrell), Livingstones fruit bat.
Birds: Echo parakeet, pink pigeon, Mauritius kestrel,
Reptiles : Round island boa, Telfair's skink, orange tailed skink, Round island skink.
Current Mauritius (and island) in-situ conservation projects by Durrell trust : Orange tailed skink project, Telfair's skink project, Round island boa project, pink pigeon project.
Past in-situ conservation projects by Durrell trust: Rodrigues fruit bat project, Livingstones fruit bat project, echo parakeet project, Mauritius kestrel project.
Other species currently and formerly from islands kept at zoo and bred ex-situ: Sumatran orangutang , Komodo dragon, Galapagos giant tortoise, Sulawesi crested macaque, barbirusa, white handed gibbon, Parma wallaby, tuatara, Sunda wrinkled hornbill, Laysan teal, Asian fairy blue bird, Java sparrow, , chestnut backed thrush, Ne-ne goose, Palawan peacock pheasant, Visayan warty pigs, Bali starling, Mindinaoa bleeding heart dove, Nicobar pigeon, Victoria crowned pigeon.