Truth or lack of knowledge
Following on from the mention of Nene above, here's a tale of developing attitudes to rare animals. Firstly, the DODO was imported to the UK and exhibited in public. It does not appear to have occurred to anyone to breed them. Remember, in those pre-Darwinian days, it was inconceivable that God would let any of his creatues become extinct. Secondly, the PASSENGER PIGEON was bred by the Earl of Derby at Knowsley in the first half of the 19th century. He bred so many he was letting them out, and quite a lot were sold off with the rest of the collection after his death. I have no record of London Zoo breeding them, but suspect that they did. Anyway, within a century of the Knowsley sale, the Passenger Pigeon was extinct. What a missed opportunity to save a species through captive propagation! Lord Derby also bred the NENE [HAWAIIAN GOOSE], founding a captive stock of which the last survivor died in France during the Second World War. Fortunately, Herbert Shipman in Hawaii had a small flock [not exactly captive, as I believe he had them free-winged at liberty]. I addition to these, there still existed a handfull of wild birds. Three of Shipman's birds went to Slimbridge, where [with a reinforcement of wild stock later on] became the ancestors of a large captive population,. Peter Scott was far-sighted enough in the early 1970s to allow the sale of [I believe] six pairs into private ownership. As a direct result, NENE are freely available now, one of the commoner 'ornamental' geese, and attempts continue to re-establish a self-maintaining wild population.